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Question 1
Correct
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Elevation of the mandible is produced primarily by which of the following muscles:
Your Answer: Temporalis, masseter and medial pterygoid
Explanation:Elevation of the mandible is generated by the temporalis, masseter and medial pterygoid muscles.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 2
Incorrect
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A 67-year-old female is admitted under your care with the complaint of shortness of breath and massive pedal oedema. There are fine crepitations up to the mid zones on both lung fields on chest auscultation. When questioned about her medication, she doesn't remember everything she takes but knows that there is a tablet to get rid of excess water.
Out of the following medications, which one increases the osmolality of the filtrate in the glomerulus and the tubule, creating an osmotic effect?Your Answer: Furosemide
Correct Answer: Mannitol
Explanation:Mannitol is an osmotic diuretic that stops the absorption of water throughout the tubule, thus increasing the osmolality of both glomerular and tubular fluid. It is used to:
1. decrease intraocular pressure in glaucoma
2. decrease intracerebral pressure
3. oliguria.Furosemide is a loop diuretic that inhibits the Na/K/2Cl transported in the ascending limb of the Loop of Henle.
Bendroflumethiazide is a thiazide diuretic which inhibits the Na/Cl transporter.
Spironolactone is a potassium-sparing diuretic that acts as an aldosterone receptor antagonist.
Acetazolamide is a carbonic anhydrase inhibitor.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 3
Incorrect
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Haemophilia B results from a deficiency in:
Your Answer: Factor VIII
Correct Answer: Factor IX
Explanation:Haemophilia B is a bleeding disorder caused by a deficiency of clotting factor IX. It is the second commonest form of haemophilia, and is rarer than haemophilia A. Haemophilia B tends to be similar to haemophilia A but less severe. The two disorders can only be distinguished by specific coagulation factor assays.
The incidence is one-fifth of that of haemophilia A. Laboratory findings demonstrate prolonged APTT, normal PT and low factor IX.
Haemophilia B inherited in an X-linked recessive fashion, affecting males born to carrier mothers.
There is also a variation called Leyden, in which factor IX levels are below 1% until puberty, when they rise, potentially reaching as high as 40-60% of normal. This is thought to be due to the effects of testosterone at puberty. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 4
Correct
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A 35-year-old man suffered a severe road traffic accident and has been brought to the hospital. As part of his treatment, he requires a blood transfusion and experiences a transfusion reaction.
The most common type of transfusion reaction is which of the following?Your Answer: Febrile transfusion reaction
Explanation:During or shortly after transfusion, febrile transfusion reactions, also known as non-haemolytic transfusion reactions, present with an unexpected temperature rise (38oC or 1oC above baseline, if baseline is 37oC). This is usually a one-off occurrence. The fever is sometimes accompanied by chills.
The most common type of transfusion reaction is febrile transfusion reactions, which occur in about 1 in every 8 transfusions.
The most common event leading to symptoms of febrile transfusion reactions is cytokine accumulation during storage of cellular components (especially platelet units). White cells secrete cytokines, and pre-storage leucodepletion has reduced this risk.
Recipient antibodies (raised as a result of previous transfusions or pregnancies) reacting to donor human leukocyte antigen (HLA) or other antigens can also cause febrile transfusion reactions. Donor lymphocytes, granulocytes, and platelets all contain these antigens.
Treatment is reassuring. Other causes should be ruled out, and antipyretics like paracetamol can help with fever relief. If another cause of fever is suspected, the transfusion should be stopped; however, if other causes of fever have been ruled out, it can be restarted at a slower rate.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 5
Correct
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An unrelated medical condition brings a 28-year-old asthmatic man to the Emergency Department. When you look over his meds, you notice that he is taking Theophylline to help with his asthma.
Which of the following medicines should you NOT prescribe?Your Answer: Ciprofloxacin
Explanation:Ciprofloxacin is a cytochrome P450 enzyme inhibitor that raises theophylline levels in the blood. As a result, co-prescribing theophylline should be avoided.
The medicines that typically impact theophylline’s half-life and plasma concentration are listed in the table below:
Drugs that increase the levels of theophylline in the blood
Drugs that lower theophylline levels in the blood
Calcium channel blockers e.g. Verapamil
Fluconazole
Cimetidine
Quinolones, e.g. ciprofloxacin
Methotrexate
Barbiturates
Carbamazepine
Phenobarbital
Macrolides, e.g. erythromycin
Phenytoin (and fosphenytoin)
Rifampicin
St. John’s wort -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 6
Incorrect
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A patient suffers a lower limb fracture that causes damage to the nerve that innervates peroneus brevis.
Peroneus brevis receives its innervation from which of the following nerves? Select ONE answer only.Your Answer: Femoral nerve
Correct Answer: Superficial peroneal nerve
Explanation:Peroneus brevis is innervated by the superficial peroneal nerve.
Peroneus longus is innervated by the superficial peroneal nerve.
Peroneus tertius is innervated by the deep peroneal nerve. -
This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 7
Incorrect
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Bendoflumethiazide may cause all of the following electrolyte imbalances EXCEPT for:
Your Answer: Hyponatraemia
Correct Answer: Hypocalcaemia
Explanation:Common side effects of thiazide diuretics include:
Excessive diuresis, postural hypotension, dehydration, renal impairment
Acid-base and electrolyte imbalance
Hypokalaemia, hyponatraemia, hypomagnesaemia, hypercalcaemia, hypochloraemic alkalosis
Metabolic imbalance
Hyperuricaemia and gout
Impaired glucose tolerance and hyperglycaemia
Altered plasma-lipid concentrations
Mild gastrointestinal disturbances -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Correct
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A 32-year-old woman with a history of bipolar disorder exhibits lithium toxicity symptoms.
Which of the following is the MOST LIKELY feature to be present?Your Answer: Clonus
Explanation:Lithium toxicity manifests itself in the following ways:
Ataxia
Clonus
Coma
Confusion
Convulsions
Diarrhoea
Increased muscle tone
Nausea and vomiting
Nephrogenic diabetes insipidus
Renal failure
Tremor -
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 9
Incorrect
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A 76-year-old man presents with complaints of double vision. Upon physical examination, it was observed that he exhibits left-sided hemiplegia and left-sided loss of joint position sense, vibratory sense and discriminatory touch. In addition, he has the inability to abduct his right eye and is holding his head towards the right side. A CT scan was ordered and showed that he has suffered a right-sided stroke.
Branches of which of the following arteries are most likely implicated in the case?Your Answer:
Correct Answer: Basilar artery
Explanation:Inferior medial pontine syndrome, also known as Foville syndrome, is one of the brainstem stroke syndromes which occurs when there is infarction of the medial inferior aspect of the pons due to occlusion of the paramedian branches of the basilar artery.
It is characterized by ipsilateral sixth nerve palsy, facial palsy, contralateral hemiparesis, contralateral loss of proprioception and vibration, ipsilateral ataxia, ipsilateral facial weakness, and lateral gaze paralysis and diplopia.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 10
Incorrect
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A 65-year-old man presents with cough and shortness of breath. His sputum is rusty in colour and is suffering from a fever. Upon examination, it was noted that he has crackles in the right upper lobe. A chest X-ray showed the presence of a right upper lobe cavitation.
Among the following microorganisms, which is considered to be mostly associated with a cavitating upper lobe pneumonia?Your Answer:
Correct Answer: Klebsiella pneumoniae
Explanation:Klebsiella pneumoniae is among the most common Gram-negative bacteria encountered by physicians worldwide and accounts for 0.5-5.0% of all cases of pneumonia. This organism can cause extensive pulmonary necrosis and frequent cavitation.
It is one of the causes that could be suspected when there is cavitatory pneumonia with or without a bulging fissure sign. Often, there can be extensive lobar opacification with air bronchograms.
A helpful feature which may help to distinguish from pneumococcal pneumonia is that Klebsiella pneumoniae develops cavitation in 30-50% of cases (in comparison, cavitation is rare in pneumococcal pneumonia). This occurs early and progresses quickly.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 11
Incorrect
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You're evaluating a 37-year-old woman who is 12 weeks pregnant. She has experienced vaginal bleeding.
Which of the following anti-D statements is correct?Your Answer:
Correct Answer: Routine antenatal prophylaxis is recommended for RhD negative women at 28 and 34 weeks
Explanation:Anti-D is an IgG antibody that targets the antigen Rhesus D (RhD). Plasma from rhesus-negative donors who have been immunised against the anti-D-antigen is used to make anti-D immunoglobulin.
Only RhD negative women are given Anti-D Ig. Women who are RhD negative do not have the RhD antigen on their RBC. If a foetus has the RhD antigen (i.e. is RhD positive) and the mother is exposed to foetal blood, she may develop antibodies to RhD that pass through the placenta and attack foetal red cells (resulting in newborn haemolytic disease). Anti-D is given to bind and neutralise foetal red cells in the maternal circulation before an immune response is triggered. In the event of a sensitising event, 500 IU Anti-D Ig should be administered intramuscularly.
The following are examples of potentially sensitising events:
Birth
Haemorrhage during pregnancy
Miscarriage
Ectopic pregnancy
Death within the womb
Amniocentesis
Chorionic villus sampling
Trauma to the abdomenThe sooner anti-D is given in the event of a sensitising event, the better; however, it is most effective within 72 hours, and the BNF states that it is still likely to have some benefit if given outside of this time frame.
At 28 and 34 weeks, RhD negative women should receive routine antenatal prophylaxis. This is regardless of whether they have previously received Anti-D for a sensitising event during the same pregnancy.
Prophylactic anti-D is not necessary before 12 weeks gestation, as confirmed by scan, in uncomplicated miscarriage (where the uterus is not instrumented), or mild, painless vaginal bleeding, as the risk of foeto-maternal haemorrhage (FMH) is negligible. In cases of therapeutic termination of pregnancy, whether by surgical or medical means, 250 IU of prophylactic anti-D immunoglobulin should be given to confirmed RhD negative women who are not known to be RhD sensitised.
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This question is part of the following fields:
- Immunological Products & Vaccines
- Pharmacology
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Question 12
Incorrect
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Regarding a case-control study, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The usual outcome measure is the relative risk.
Explanation:A case-control study is a longitudinal, retrospective, observational study which investigates the relationship between a risk factor and one or more outcomes. This is done by selecting patients who already have a specific disease (cases), matching them to patients who do not (controls) and then collecting data from the patients to compare past exposure to a possible risk factor. The usual outcome measure is the odds ratio.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 13
Incorrect
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During swallowing, which of the following structures primarily closes the tracheal opening:
Your Answer:
Correct Answer: Epiglottis
Explanation:The vocal cords of the larynx are strongly
approximated, and the larynx is pulled upward
and anteriorly by the neck muscles. These actions,
combined with the presence of ligaments that
prevent upward movement of the epiglottis, cause
the epiglottis to swing back over the opening
of the larynx. All these effects acting together
prevent the passage of food into the nose and
trachea. Most essential is the tight approximation
of the vocal cords, but the epiglottis helps to
prevent food from ever getting as far as the vocal
cords. Destruction of the vocal cords or of the
muscles that approximate them can cause
strangulation. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 14
Incorrect
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Which of the following statements is correct with regards to natural killer cells?
Your Answer:
Correct Answer: They are part of the innate immune system.
Explanation:Natural Killer (NK) Cells are lymphocytes in the same family as T and B cells, which come from a common progenitor. They are cytotoxic CD8 positive cells that do not have the T-cell receptor. They are very big cells with cytoplasmic granules and are designed to kill target cells with a low level of expression of HLA class I molecules.
Examples include during a viral infection or on a malignant cell. NK cells display several receptors for HLA molecules on their surface, and when HLA is expressed on the target cell, these deliver an inhibitory signal into the NK cell. Absent HLA molecules on the target cell cause this inhibitory signal to get lost and as a result, the NK cell can then kill its target. Also, NK cells display antibody-dependent cell-mediated cytotoxicity, where antibody binds to antigen on the surface of the target cell. The NK cells then bind to the Fc portion of the bound antibody and kill the target cell. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 15
Incorrect
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You've been asked to visit a 20-year-old patient  who has been complaining of stomach pain, diarrhoea, and bloating. The GP recently saw the patient and is now looking into numerous possible reasons for stomach hypermotility.
Which of the following factors contributes to increased stomach motility?Your Answer:
Correct Answer: Gastrin
Explanation:Gastrin is a peptide hormone that aids in gastric motility by stimulating the generation of gastric acid by the parietal cells of the stomach. G-cells in the stomach’s pyloric antrum, the duodenum, and the pancreas release it.
The following stimuli cause the release of gastrin:
Stimulation of the vagus nerve
Hypercalcaemia
stomach bloating
Proteins that have been partially digested, particularly amino acids.
The presence of acid and somatostatin inhibits the release of gastrin.
Gastrin’s main actions are as follows:
Gastric parietal cells are stimulated to release hydrochloric acid.
ECL cells are stimulated to produce histamine.
Gastric parietal cell maturation and fundal growth stimulation
Causes the secretion of pepsinogen by the gastric chief cells.
Improves antral muscle mobility
stimulates gastric contractions
Increases gastric emptying rate and stimulates pancreatic secretion
Gallbladder emptying is induced. -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 16
Incorrect
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A patient with a diagnosis of HIV presents with a fever, sore throat, and general malaise and you are concerned the patient may have an AIDS defining illness.
Which one of these, according to the CDC definition, would mean a patient infected with HIV has AIDS?
Your Answer:
Correct Answer: CD4 T-cell percentage of total lymphocytes of less than 15%
Explanation:According to the CDC definition, a patient co-infected with HIV can be diagnosed with AIDS if he or she has:
A CD4 T-cell count of less than 200 cells/mm3 or;
A CD4 T-cell percentage of total lymphocytes of less than 15% or;
An AIDS defining infectionA Streptococcal throat infection is not an AIDS defining infection.
A normal CD4 count ranges from 500-1000 cells/mm3. A CD4 (not CD8) count of less than 200 cells/mm3 is AIDS defining.
The CD4 count can vary from day to day and depending upon the time that the blood test is taken. It can also be affected by the presence of other infections or illnesses. Treatment with anti-retroviral therapy should be considered at CD4 count of less than 350 cells/mm3.
Serum concentrations of the p24 antigen (the viral protein that makes up most of the core of the HIV) are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 17
Incorrect
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You are taking care of a 55-year-old male patient who is a weightlifter. He is suspected of having a direct inguinal hernia. Where would this hernia appear?
Your Answer:
Correct Answer: Medial to the inferior epigastric artery
Explanation:A direct inguinal hernia is a form of groin hernia that occurs when abdominal viscera protrude through a weakness in the posterior wall of the inguinal canal, notably through Hesselbach’s triangle, medial to the inferior epigastric veins.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 18
Incorrect
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A 58-year-old woman presents with symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that she has a full, plethoric aspect to her face, as well as significant supraclavicular fat pads, when you examine her. She has previously been diagnosed with Cushing's syndrome.
Which of the following biochemical profiles best supports this diagnosis?Your Answer:
Correct Answer: Hypokalaemic metabolic alkalosis
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.
A typical biochemical profile can help establish a diagnosis of Cushing’s syndrome. The following are the primary characteristics:
Hypokalaemia
Alkalosis metabolique -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 19
Incorrect
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The fracture of the medial epicondyle will cause damage to the ulnar nerve. Which of the following motions would be impaired by this type of injury?
Your Answer:
Correct Answer: Adduction of the thumb
Explanation:Fracture of the medial epicondyle is most likely to result in damage to the ulnar nerve.
The three hypothenar muscles, two medial lumbricals, seven interossei, the adductor pollicis, and the deep head of the flexor pollicis brevis are all innervated by the deep branch of the ulnar nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Incorrect
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A 58-year-old man showing symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that he has a full, plethoric aspect to his face, as well as significant supraclavicular fat pads, when you examine him. His blood pressure is 158/942Â mmHg, and his glucose tolerance has lately been impaired. His potassium level is 3.2Â mmol/L.
What is the MOST LIKELY diagnosis?Your Answer:
Correct Answer: Cushing’s syndrome
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.
Cushing’s syndrome has a wide range of clinical manifestations that are dependent on the degree of cortisol overproduction. The appearance might be vague and the diagnosis difficult to detect when cortisol levels are just somewhat elevated. On the other hand, in long-term cases of severely increased cortisol levels, the presentation might be colourful and the diagnosis simple.
Cushing’s syndrome has the following clinical features:
Obesity and weight growth in the true sense
Supraclavicular fat pads are fat pads that are located above the clavicle.
Buffalo hump
Fullness and plethora of the face (‘moon facies’)
Muscle atrophy and weakening at the proximal level
Diabetes mellitus, also known as impaired glucose tolerance
Hypertension
Skin thinning and bruising
Depression
Hirsutism
Acne
Osteoporosis
Amenorrhoea or oligomenorrhoeaCortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater during the whole 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed. As a result, random cortisol testing is not an effective screening technique and is not advised.
The following are the two most common first-line screening tests:
Cortisol levels in the urine are measured every 24 hours.
A diagnosis of Cushing’s syndrome can be made if more than two collections measure cortisol excretion more than three times the upper limit of normal.
Physical stress (e.g., excessive exercise, trauma), mental stress (e.g., sadness), alcohol or drug misuse, complex diabetes, and pregnancy can all cause false positives.
Renal dysfunction, inadequate collection, and cyclical Cushing’s disease can all cause false negatives.
The overnight low-dose dexamethasone suppression test (LDDST) involves giving 1 mg of dexamethasone at 11 p.m. and measuring blood cortisol levels at 8 a.m. the next day.
Cushing’s syndrome is diagnosed when cortisol is not suppressed to less than 50 nmol/L.
It might be difficult to tell the difference between mild Cushing’s disease and normal cortisol production.
False positives can occur as a result of depression, severe systemic sickness, renal failure, prolonged alcohol misuse, old age, and the use of hepatic enzyme-inducing medicines, among other things.
False negatives are extremely uncommon in Cushing’s disease patients.A characteristic biochemical picture might also be helpful in confirming the diagnosis of Cushing’s syndrome. The following are the primary characteristics:
Hypokalaemia
Alkalosis metabolique -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 21
Incorrect
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A patient complains of stomach ache. You see a midline scar in the epigastric area when you examine the abdomen. Upon further interrogation, the patient reveals that she had a subtotal gastrectomy for recurring stomach ulcers several years ago. The stomach mucosa secretes a variety of vital compounds, and her ability to secrete some of these molecules has been harmed as a result of his surgery.
The stomach G-cells are responsible for which of the following?Your Answer:
Correct Answer: Secretion of gastrin
Explanation:G-cells are a type of cell found in the stomach’s pyloric antrum, duodenum, and pancreas. The secretion of the peptide hormone gastrin is their major function.
The table below summarizes the many cell types found in the stomach, as well as the substances secreted by each cell type and the function of the secretion:
Cell type/ Substance secreted/ Function of secretion
Parietal cells/ Hydrochloric acid/ Kills microbes and activates pepsinogen
Parietal cells/ Intrinsic factor/Binds to vitamin B12 and facilitates its absorption
Chief cells/ Pepsinogen/ Protein digestion
Chief cells/ Gastric lipase/ Fat digestion
G-cells/ Gastrin/ Stimulates gastric acid secretion
Enterochromaffin-like cells (ECL cells) /Histamine/ Stimulates gastric acid secretion
Mucous-neck cells/ Mucous and bicarbonate/ Protects stomach epithelium from acid
D-cells/ Somatostatin/ Inhibits gastric acid secretion -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 22
Incorrect
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A patient presents with a lump for a dermatological examination. There is a circumscribed skin elevation measuring 0.3 cm in diameter seen on examination.
Which one of these best describes the lump you have found on examination?Your Answer:
Correct Answer: Papule
Explanation:A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A bulla is a visible collection of clear fluid measuring greater than 0.5 cm in diameter.
A furuncle, or boil, is a pyogenic infection of the hair follicle commonly caused by infection with Staphylococcus aureus.
A pustule is a small visible skin elevation containing an accumulation of pus.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 23
Incorrect
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Depression of the eyeball is primarily produced by which of the following muscles:
Your Answer:
Correct Answer: Inferior rectus and superior oblique
Explanation:Depression of the eyeball is produced by the inferior rectus and the superior oblique muscles.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 24
Incorrect
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Which of the following muscles is least likely to be involved in forceful expiration:
Your Answer:
Correct Answer: External intercostal muscles
Explanation:Forceful expiration is primarily produced by the deeper thoracic muscles (internal and innermost intercostal muscles, subcostals and transversus thoracis) aided by contraction of the abdominal wall muscles which increase intra-abdominal pressure thus further reducing the volume of the thorax.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 25
Incorrect
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Which of the following is a primary action of aldosterone:
Your Answer:
Correct Answer: Renal sodium reabsorption
Explanation:Aldosterone acts mainly at the renal distal convoluted tubule (DCT) to cause sodium retention and potassium loss. It increases the synthesis of transport mechanisms in the distal nephron including the Na+pump, Na+/H+symporter, and Na+and K+channels in principal cells, and H+ATPase in intercalated cells. Na+(and thus water) reabsorption and K+and H+secretion are thereby enhanced.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Incorrect
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A 72-year-old woman presents to your clinic with worsening oedema. She has ischaemic heart disease and heart failure. You decide to add a loop diuretic to her current drug regime to control the oedema. Which of the following is a contraindication to using a loop diuretic?
Your Answer:
Correct Answer: Anuria
Explanation:Loop diuretics are drugs used to manage and treat fluid overload associated with CHF, liver cirrhosis, and renal disease. The drugs commonly used are:
- Furosemide
- Bumetanide
- Torsemide
- Ethacrynic Acid
Loop diuretics inhibit the Na-K-Cl pump in the ascending loop of Henle, resulting in salt-water excretion. This relieves congestion and reduces oedema.
The contra-indications to the use of loop diuretics are:
1. Anuria
2. Comatose and precomatose states associated with liver cirrhosis
3. Renal failure due to nephrotoxic or hepatotoxic drugs
4. Severe hypokalaemia
5. Severe hyponatremia
6. History of hypersensitivity to furosemide, bumetanide, or torsemide (or sulphonamides)The following conditions or states are not contraindications, but loop diuretics needs to be used cautiously in these conditions:
1. Diabetes (but hyperglycaemia less likely than with thiazides)
2. Gout
3. Hypotension (correct before initiation of treatment)
4. Hypovolaemia (Correct before initiation of treatment) -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 27
Incorrect
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You review a 37-year-old man with a history of intravenous drug abuse who admits to sharing needles in the past. He has a flu-like illness and a rash. Concerned he may be experiencing an HIV seroconversion illness, you order a test.
Which of these tests is most reliably used to diagnose HIV at this stage?
Your Answer:
Correct Answer: p24 antigen test
Explanation:Serum concentrations of the p24 antigen are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection. P24 is the viral protein that makes up most of the core of the HIV.
ELISA and other antibody tests, though a very sensitive way of detecting the presence of HIV, cannot be used in the early stages of the disease. This is because of the window period of 6-12 weeks before antibodies are produced. These tests will be negative during a seroconversion illness.
The ‘rapid HIV test’ is an HIV antibody test. It will also be negative during the ‘window period’ since it takes time for antibodies to be produced. It is called the ‘rapid test’ as it can detect antibodies in blood or saliva much quicker than the other antibody tests and results are often back within 20 minutes.
CD4 and CD8 counts are usually normal in the early stages of the HIV infection and cannot be used in this case.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 28
Incorrect
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A patient presents with a rash for a dermatological examination. A flat circumscribed area of discoloured skin measuring 0.7 cm in diameter is seen on examination.
What is the best description of this rash that you have found on examination?
Your Answer:
Correct Answer: Macule
Explanation:A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
A vesicle is a visible collection of clear fluid measuring less than 0.5 cm in diameter.
A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 29
Incorrect
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Which of the following best describes the process of opsonisation:
Your Answer:
Correct Answer: The coating of foreign particles with molecules which allow easier recognition of that cell by phagocytes
Explanation:An opsonin is any molecule that enhances phagocytosis by marking an antigen for an immune response, for example, immunoglobulin or complement. Opsonisation is the molecular mechanism whereby molecules, microbes, or apoptotic cells are chemically modified to have a stronger attraction to the cell surface receptors on phagocytes and natural killer cells. With the antigen coated in opsonins, binding to immune cells is greatly enhanced. Opsonisation also mediates phagocytosis via signal cascades from cell surface receptors.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 30
Incorrect
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In a VF arrest, a 6-year-old child is brought to your Emergency Department resuscitation area. He weighs 16 kilogrammes. He's had three DC shocks, but he's still in VF and doesn't have an output.
What amiodarone dose should he get now, according to the most recent APLS guidelines?Your Answer:
Correct Answer: 80 mg
Explanation:In a shockable (Vf/pVT) paediatric cardiac arrest, amiodarone should be administered after the third and fifth shocks. The dose is 5 mg/kg (maximum 300 mg) and should be administered over a three-minute period. If at all possible, administration via a central line is recommended.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 31
Incorrect
-
When the pulmonary artery is completely blocked, what is the ventilation over perfusion ratio for the area that it supplies?
Your Answer:
Correct Answer: Infinity
Explanation:The ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the matching ventilation and perfusion.
A pulmonary artery carries deoxygenated blood from the right side of the heart to the lungs. When a large pulmonary embolus completed blocked a pulmonary artery the alveoli were ventilated but not perfused at all, then the V/Q ratio would be infinity.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 32
Incorrect
-
A 40-year-old female presents to the orthopaedic clinic complaining of pain and limited range of motion in the right elbow for the past two days. On examination, the right elbow is extremely tender with erythema and warmth of the overlying skin due to acute inflammation.
Which ONE of the following statements is true with regards to acute inflammation?Your Answer:
Correct Answer: Neutrophils are activated and adhere to the endothelium as a result of interaction with endothelial cell adhesion molecules
Explanation:Acute inflammation is defined as inflammation occurring within minutes to hours in response to an injury lasting for less than two weeks.
Acute inflammation
Rapid onset (minutes to hours)
Quick resolution (usually days)Chronic inflammation
May last weeks, months, or yearsThere are five cardinal signs of inflammation:
1) Pain
2) Redness
3) Warmth
4) Oedema
5) Loss of functionDuring acute inflammation, neutrophils are activated and attracted to the site of inflammation in response to various interleukins and cytokines. This process takes place via the following mechanism:
1) Margination
Neutrophils flow nearer the vessel wall rather than in the axial stream, which is referred to as margination
2) Rolling along the surface of vascular endothelium
3) Adhesion to the endothelium by interaction with adhesion molecules (ICAMS and VCAMS)
4) Diapedesis is the movement of neutrophils from the endothelial cells into the interstitial space by squeezing through the gaps between adjacent endothelial cellsBradykinin and histamine are both responsible for vasodilation which causes oedema and decreases intravascular osmotic pressure.
Neutrophils dominate early (<2 days)
– Many in the bloodstream
– Attach firmly to adhesion molecules
– Apoptosis after 24-48hrs
Monocytes/macrophages dominate late (>2 days)
– Live longer
– Replicate in tissues -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 33
Incorrect
-
In adult advanced life support, which of the following best describes the correct administration of adrenaline for a non-shockable rhythm:
Your Answer:
Correct Answer: Give 1 mg of adrenaline as soon as intravenous access is achieved and every 3 - 5 minutes thereafter
Explanation:IV adrenaline 1 mg (10 mL of 1:10,000 solution) should be given after 3 shocks and every 3 – 5 minutes/after alternate shocks thereafter.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 34
Incorrect
-
Regarding the flexor digitorum profundus muscle, which of the following is true?
Your Answer:
Correct Answer: The medial aspect of the muscle is innervated by the ulnar nerve
Explanation:Flexor digitorum profundus is a fusiform muscle located deep within the anterior (flexor) compartment of the forearm. Along with the flexor pollicis longus and pronator quadratus muscles, it comprises the deep flexor compartment of the forearm.
Flexor digitorum profundus has a dual innervation:
(1) The medial part of the muscle, that inserts to the fourth and fifth digits, is innervated by the ulnar nerve (C8-T1);
(2) The lateral part, that inserts to the second and third digits, is innervated by the median nerve, via anterior interosseous branch (C8-T1).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 35
Incorrect
-
Which of the following statements is INCORRECT. Fick's law tells us that the rate of diffusion of a gas across a membrane increases as:
Your Answer:
Correct Answer: the partial pressure gradient decreases.
Explanation:Fick’s law tells us that the rate of diffusion of a gas increases:
the larger the surface area involved in gas exchange
the greater the partial pressure gradient across the membrane
the thinner the membrane
the more soluble the gas in the membrane
the lower the molecular weight of the gas -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 36
Incorrect
-
During the second and third trimesters of her pregnancy, a 36-year-old woman is given a drug to treat a medical condition. The foetus has developed hypoperfusion and the oligohydramnios sequence as a result of this.
Which of the following drugs is most likely to be the cause of these side effects?Your Answer:
Correct Answer: Ramipril
Explanation:Hypoperfusion, renal failure, and the oligohydramnios sequence are all linked to ACE inhibitor use in the second and third trimesters.
The oligohydramnios sequence refers to a foetus’ or neonate’s atypical physical appearance as a result of oligohydramnios in the uterus. It’s also linked to aortic arch obstructive malformations and patent ductus arteriosus.
The inhibitory effects on the renin-angiotensin-aldosterone system appear to be the cause of these defects. To avoid these risks, ACE inhibitors should be stopped before the second trimester.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 37
Incorrect
-
A 19-year-old with a longstanding history of asthma presents to the ED with worsening symptoms of cough and wheeze and a peak expiratory flow rate (PEFR) measurement is taken.
Which statement concerning PEFR is true?Your Answer:
Correct Answer: PEFR is dependent upon the patient's height
Explanation:The maximum flow rate generated during a forceful exhalation, after maximal inspiration is the peak expiratory flow rate (PEFR).
PEFR is dependent upon initial lung volume. It is, therefore, dependant on patient’s age, sex and height.
PEFR is dependent on voluntary effort and muscular strength of the patient.
PEFR is decreased with increasing airway resistance, e.g. in asthma, and it correlates well with the forced expiratory volume in one second (FEV1) value measured in spirometry. This correlation decreases in patients with asthma as airflow decreases.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 38
Incorrect
-
A 25 year old woman who is a known diabetic is brought to the ED with diabetic ketoacidosis. She promptly received an insulin infusion. Which of the following are expected to increase upon infusion of insulin?
Your Answer:
Correct Answer: Blood pH
Explanation:Ketoacidosis is characterized by hyperglycaemia, glycosuria, hyperkalaemia, and metabolic acidosis with respiratory compensation. An insulin infusion would be able to address these by lowering blood glucose through increased insulin-mediated cellular uptake, lowering urine glucose concentration as cellular glucose uptake is increased, decreasing K+ in her blood by shifting it into cells, and increasing blood ph by addressing the metabolic acidosis. The metabolic acidosis is addressed by the reduction of ketoacids production thereby returning her blood ph to normal and reducing the need for compensatory hyperventilation.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 39
Incorrect
-
Regarding fat digestion, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Chylomicrons are exocytosed from enterocytes to enter lacteals and thus the lymphatic system.
Explanation:Dietary fat is chiefly composed of triglycerides (esters of free fatty acids and glycerol which may be saturated or unsaturated). The essential fatty acids are linoleic acid and alpha-linoleic acid, which cannot be manufactured in the body. Dietary fat provides 37 kJ (9 kcal) of energy per gram. Fats are digested almost entirely in the small intestine and are only released from the stomach into the duodenum at the rate at which they can be digested.
Pancreatic lipase is the most significant enzyme for fat digestion. In the duodenum fat is emulsified by bile acids, a process where larger lipid droplets are broken down into much smaller droplets providing a greater surface area for enzymatic digestion. Micelles are arranged so that hydrophobic lipid molecules lie in the centre, surrounded by bile acids arranged such the outer region is hydrophilic. Dietary and synthesised lipids are incorporated into chylomicrons in the Golgi body, which are exocytosed from the basolateral membrane to enter lacteals and thus the lymphatic system. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 40
Incorrect
-
Na+ is reabsorbed via the Na+/K+/2Cl-symporter in which part of the loop of Henle?
Your Answer:
Correct Answer: Thick ascending limb
Explanation:In the thick ascending limb is the part of the loop of Henle in which there is active reabsorption of Na+and Cl- ions from the tubular fluid. This occurs via the Na+/K+/2Cl-symporter on the apical membrane.
This mechanism is by:
1. Na+ions are transported across the basolateral membrane by Na+pumps and the Cl-ions by diffusion.
2. K+leaks back into the tubular fluid via apical ROMK K+channels which creates a positive charge.
3. This positive charge drives the reabsorption of cations (Na+, K+, Ca2+, Mg2+) through paracellular pathways.
4. Due to the thick ascending limb being impermeable to water, the tubular fluid osmolality is reduced by ion reabsorption, the interstitial fluid osmolality is increased, and an osmotic difference is created. -
This question is part of the following fields:
- Physiology
- Renal
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Question 41
Incorrect
-
What is the appropriate dose of 1:1000 adrenaline solution for a 15-year-old patient with suspected anaphylactic shock?
Your Answer:
Correct Answer: 500 micrograms intramuscularly
Explanation:1: 1000 Adrenaline solution dosage for children above the age of 12 and adults, including pregnant women (over 50 kg) is 0.50 mL, which is equivalent to 500 mcg of adrenaline.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 42
Incorrect
-
A 17-year-old male patient diagnosed with cystic fibrosis is experiencing shortness of breath, coughing, and flu-like symptoms. His X-ray results shows atelectasis, or collapsed lung, specifically in his lower right lung. All of the following statements are true regarding collapsed lungs, except for which one.
Your Answer:
Correct Answer: Atelectasis is an example of a perfusion defect
Explanation:Atelectasis is a complete or partial collapse of the lung. It occurs when the alveoli deflate or are filled with alveolar fluid. It is considered a ventilation defect of the alveoli due to cystic fibrosis. It is not a perfusion defect. A perfusion defect will produce pathological dead space in which the lung alveoli are ventilated adequately but are not perfused, and there is no gas exchange. While with atelectasis, the alveoli remain perfused. However, there is impaired oxygen delivery and intrapulmonary shunting of blood will be present in the collapsed area. Since there is no exchange of gas at the capillary-alveolar interface of the collapsed segments, the pulmonary capillary blood will have similar PO2 and PCO2.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 43
Incorrect
-
A 22 year old male has been stabbed and is brought to the ED with a stab wound to his upper limb. On examination, the patient is unable to flex the distal interphalangeal joints of the ring and little finger. However, the proximal interphalangeal joint is intact. The most likely affected nerve is which of the following, and at which level is this occurring?
Your Answer:
Correct Answer: Ulnar nerve at elbow
Explanation:The medial half of the flexor digitorum profundus is innervated by the ulnar nerve. Paralysis of this muscle results in loss of flexion at the distal interphalangeal joint of the ring and little finger.
Flexion at the proximal interphalangeal joint is preserved as this is a function of the flexor digitorum superficialis which is innervated by the median nerve.
The ulnar nerve is not correct as ulnar nerve injury at the wrist would not affect the long flexors, and the injury must have been more proximal. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 44
Incorrect
-
Regarding haemoglobin, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Haemoglobin synthesis occurs in mature erythrocytes.
Explanation:Haemoglobin is composed of four polypeptide globin chains each with its own iron containing haem molecule. Haem synthesis occurs largely in the mitochondria by a series of biochemical reactions commencing with the condensation of glycine and succinyl coenzyme A under the action of the key rate-limiting enzyme delta-aminolevulinic acid (ALA) synthase. The globin chains are synthesised by ribosomes in the cytosol. Haemoglobin synthesis only occurs in immature red blood cells.
There are three types of haemoglobin in normal adult blood: haemoglobin A, A2 and F:
– Normal adult haemoglobin (HbA) makes up about 96 – 98 % of total adult haemoglobin, and consists of two alpha (α) and two beta (β) globin chains.Â
– Haemoglobin A2 (HbA2), a normal variant of adult haemoglobin, makes up about 1.5 – 3.5 % of total adult haemoglobin and consists of two α and two delta (δ) globin chains.
– Foetal haemoglobin is the main Hb in the later two-thirds of foetal life and in the newborn until approximately 12 weeks of age. Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin.Â
Red cells are destroyed by macrophages in the liver and spleen after , 120 days. The haem group is split from the haemoglobin and converted to biliverdin and then bilirubin. The iron is conserved and recycled to plasma via transferrin or stored in macrophages as ferritin and haemosiderin. An increased rate of haemoglobin breakdown results in excess bilirubin and jaundice. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 45
Incorrect
-
A 70-year-old woman presents with right-sided loss of pain and temperature sense on the body as well as left-sided loss of pain and temperature sense on the face. She also has complaints of vertigo, nausea, and tinnitus. Further examination of her cranial nerves suggest the presence of Horner's Syndrome. An MRI and CT scan was ordered and results showed that she is suffering from a left-sided stroke.
Branches of which of the following arteries are most likely implicated in the case?Your Answer:
Correct Answer: Posterior inferior cerebellar artery
Explanation:Wallenberg syndrome is also known as lateral medullary syndrome and posterior inferior cerebellar artery syndrome. It is the most common posterior circulation ischemic stroke syndrome. The primary pathology of Wallenberg syndrome is occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches.
It is characterized by vertigo with nystagmus, nausea and vomiting, and sometimes hiccups, dysphonia, dysarthria, and dysphagia often present with ipsilateral loss of gag reflex, ipsilateral ataxia with a tendency to fall to the ipsilateral side, pain and numbness with impaired facial sensation on the face, impaired taste sensation, and impaired pain and temperature sensation in the arms and legs.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 46
Incorrect
-
A 17-year-old student presents with a headache and petechial rash. A diagnosis of meningitis was suspected, with a causative agent of Neisseria meningitidis.
Which of the following statements is considered correct regarding Neisseria meningitidis?Your Answer:
Correct Answer: The antiphagocytic polysaccharide capsule is the main determinant of its pathogenicity
Explanation:N. meningitidis is a Gram-negative cocci and can be found as a commensal as well as an invasive pathogen. It is an important etiologic agent of endemic and epidemic meningitis and meningococcaemia and rarely pneumonia, purulent arthritis, or endophthalmitis. N. meningitidis has also been recovered from urogenital and rectal sites as a result of oral-genital contact. Meningococcal carriage, usually involving nonencapsulated strains, may cause an increase in protective antibody against the pathogenic strains. Of the 12 meningococcal encapsulated serogroups, A, B, C, Y, and W-135 account for most cases of disease in the world. N. meningitidis possesses a polysaccharide capsule that is antiphagocytic and serves as an important virulence factor.
It can be found on the mucosal surfaces of the nasopharynx and oropharynx in 30% of the human population. The organism is transmitted by close contact with respiratory droplet secretions from a carrier to a new host. Only a few newly colonized hosts develop meningococcal disease, with the highest incidence being found in infants and adolescents.
The quadrivalent vaccine Menactra is a polysaccharide-protein conjugated vaccine with antigens to serogroups A, C, Y, and W-135. This conjugate vaccine is licensed for people 2 to 55 years old. This vaccine does not protect against meningitis caused by serogroup B because group B polysaccharide is a very poor immunogen in humans.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 47
Incorrect
-
An injury to the brachial plexus can cause Erb's palsy. The following is expected to happen to a patient suffering from this condition, except for which one:
Your Answer:
Correct Answer: Weakness of medial rotation of the arm
Explanation:Erb’s palsy can be caused by a traumatic force downward on the upper arm and shoulder that damages the upper root of the brachial plexus.
The patient will lose shoulder abduction (deltoid, supraspinatus), shoulder external rotation (infraspinatus), and elbow flexion as a result of this condition (biceps, brachialis).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 48
Incorrect
-
You are about to perform an emergency pericardiocentesis on a 26-year-old male who was involved in a car accident and is suspected of having cardiac tamponade due to signs of hypotension, muffled heart sounds, and distended neck veins. Where should you insert the needle to relieve tamponade?
Your Answer:
Correct Answer: Inferior and to the left of the xiphochondral junction
Explanation:Pericardiocentesis is a procedure that removes excess fluid from the pericardium. As a result, it’s used in cases of cardiac tamponade, which occurs when there’s too much fluid in the space around the heart.
During the procedure, a needle and a small catheter are inserted 1 to 2 cm inferior and to the left of the xiphochondral junction into the pericardial cavity.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 49
Incorrect
-
Regarding gas gangrene, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Infection is characterised by rapidly spreading tissue myonecrosis with crepitus.
Explanation:Gas gangrene usually occurs within 3 days of injury, and is characterised by pain, rapidly spreading oedema, myositis, necrosis, palpable crepitus and systemic toxicity. Diagnosis is clinical and laboratory confirmation should not delay urgent surgical intervention. Hyperbaric oxygen therapy can be considered in addition to surgery and antibiotic therapy, to stop toxin production and inhibit bacteria from replicating and spreading (as Clostridium spp. are obligate anaerobes).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 50
Incorrect
-
Which of the following drugs used in the management of hyperkalaemia does not affect serum potassium levels:
Your Answer:
Correct Answer: Calcium gluconate
Explanation:Calcium gluconate is given to antagonise cardiac cell membrane excitability to reduce the risk of arrhythmias. It has no effect on serum potassium levels unlike the alternative drugs listed above.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 51
Incorrect
-
An analytical cohort study aimed to determine a relationship between intake of dietary calcium and incidence of hip fractures among post-menopausal women. The following are the data obtained from the study:
No. of post-menopausal women who took Calcium: 500
No. of post-menopausal women who took Calcium and suffered a hip fracture: 10
No. of post-menopausal women who took placebo: 500
No. of post-menopausal women who took placebo and suffered a hip fracture: 25
Compute for the absolute risk reduction of a hip fracture.Your Answer:
Correct Answer: 0.03
Explanation:Absolute risk reduction (ARR) is computed as the difference between the absolute risk in the control group (ARC) and the absolute risk in the treatment group (ART).
ARR = ARC-ART
ARR = (25/500) – (10/500)
ARR = 0.03 -
This question is part of the following fields:
- Evidence Based Medicine
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Question 52
Incorrect
-
A 7-year old boy is referred to the Paediatrics Department due to slurred speech. Upon further examination, the attending physician noted the presence of dysdiadochokinesia, intention tremors, and nystagmus. An MRI is taken, which revealed a brain tumour.
Which of the following options is the most probable diagnosis given the clinical features of the patient?Your Answer:
Correct Answer: Astrocytoma of cerebellum
Explanation:Pilocytic astrocytoma (PCA), previously known as cystic cerebellar astrocytoma or juvenile pilocytic astrocytoma, was first described in 1931 by Harvey Cushing, based on a case series of cerebellar astrocytomas; though he never used these terms but rather described a spongioblastoma. They are low-grade, and usually well-circumscribed tumours, which tend to occur in young patients. By the World Health Organization (WHO) classification of central nervous system tumours, they are considered grade I gliomas and have a good prognosis.
PCA most commonly occurs in the cerebellum but can also occur in the optic pathway, hypothalamus, and brainstem. They can also occur in the cerebral hemispheres, although this tends to be the case in young adults. Presentation and treatment vary for PCA in other locations. Glial cells include astrocytes, oligodendrocytes, ependymal cells, and microglia. Astrocytic tumours arise from astrocytes and are the most common tumour of glial origin. The WHO 2016 categorized these tumours as either diffuse gliomas or other astrocytic tumours. Diffuse gliomas include grade II and III diffuse astrocytomas, grade IV glioblastoma, and diffuse gliomas of childhood. The other astrocytic tumours group include PCA, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, and anaplastic pleomorphic xanthoastrocytoma.
PCA can present with symptoms secondary to the posterior fossa mass effect. This may include obstructive hydrocephalus, with resultant headache, nausea and vomiting, and papilledema. If hydrocephalus occurs before the fusion of the cranial sutures (<18-months-of-age), then an increase in head circumference will likely occur. Lesions of the cerebellar hemisphere result in peripheral ataxia, dysmetria, intention tremor, nystagmus, and dysarthria. In contrast, lesions of the vermis cause a broad-based gait, truncal ataxia, and titubation. Posterior fossa lesions can also cause cranial nerve palsies. Diplopia may occur due to abducens palsy from the stretching of the nerve. They may also have blurred vision due to papilledema. Seizures are rare with posterior fossa lesions.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 53
Incorrect
-
You received a patient with a 2-day history of diarrhoea and vomiting. Later, after examination, the patient was found to have progressive symmetric descending flaccid paralysis, initial development of blurred vision, dysphagia, and weakness of the upper limbs. The patient is apyrexial and his observations are all normal. Which of the following pathogens is responsible for the said symptoms?
Your Answer:
Correct Answer: Clostridium botulinum
Explanation:A botulism infection results in neuroparalysis caused by the neurotoxin generated by Clostridium botulinum.
Food-borne botulism symptoms often appear 12-36 hours after ingestion of the toxin-containing food and may include nausea, vomiting, stomach discomfort, and diarrhoea at first. The most common neurological pattern is an acute onset of bilateral cranial neuropathies with symmetric declining weakening.
Other distinguishing characteristics include the absence of fever, the absence of cognitive abnormalities, the presence of a normal heart rate and blood pressure, and the absence of sensory defects.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 54
Incorrect
-
Which type of collagen is initially laid down in early wound healing:
Your Answer:
Correct Answer: III
Explanation:Fibroblasts migrate to the wound (about 2 – 5 days after wounding), proliferate and secrete extracellular matrix comprising mainly collagen (type III) and fibronectin to plug the gap.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 55
Incorrect
-
Which of the following statements is not true regarding ion channels?
Your Answer:
Correct Answer: Ion channels provide a charged, hydrophobic pore through which ions can diffuse across the lipid bilayer.
Explanation:Ion channels are pore-forming protein complexes that facilitate the flow of ions across the hydrophobic core of cell membranes. They are present in the plasma membrane and membranes of intracellular organelles of all cells, and perform essential physiological functions. They provide a charged, hydrophilic pore through which ions can move across the lipid bilayer. They are selective for particular ions and their pores may be opened or closed. Because of this ability to open and close, ion channels allow the cell to have the ability to closely control the movement of ions across the membrane. Gating refers to the transition between an open and closed ion channel state, and is brought about by a conformationational change in the protein subunits that open or close the ion-permeable pore.
Ion channels can be:
1. voltage-gated these are regulated according to the potential difference across the cell membrane or
2. ligand-gated – these are regulated by the presence of a specific signal molecule. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 56
Incorrect
-
Which of the following best describes a natural killer cell:
Your Answer:
Correct Answer: A large granular lymphocyte that kills by inducing target cell apoptosis.
Explanation:Natural killer (NK) cells are cytotoxic CD8 positive cells that lack the T-cell receptor. They are large cells with cytoplasmic granules. NK cells are designed to kill target cells that have a low level of expression of HLA class I molecules, such as may occur during viral infection or on a malignant cell. NK cells do this by displaying several receptors for HLA molecules on their surface. When HLA is expressed on the target cell these deliver an inhibitory signal into the NK cell. When HLA molecules are absent on the target cell this inhibitory signal is lost and the NK cell can then kill its target. In addition, NK cells display antibody-dependent cell-mediated cytotoxicity. In this, antibody binds to antigen on the surface of the target cell and then NK cells bind to the Fc portion of the bound antibody and kill the target cell.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 57
Incorrect
-
The most common source of healthcare-associated bacteraemia is:
Your Answer:
Correct Answer: Intravenous cannula
Explanation:Healthcare-associated bacteraemia is most commonly caused by intravenous access. Any intravenous device that is left in place for a long time increases the risk of infection. It allows bacteria like Staphylococcus aureus and Staphylococcus epidermidis to enter the body.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 58
Incorrect
-
A 28-year-old patient is intubated and has a central venous catheter inserted after being diagnosed with septic shock. You keep track of her central venous pressure.
The normal value for central venous pressure is which of the following?Your Answer:
Correct Answer: 0-8 cmH 2 O
Explanation:The pressure measured in the right atrium or superior vena cava is known as central venous pressure (CVP). In a spontaneously breathing subject, the usual CVP value is 0-8 cmH2O (0-6 mmHg).
At the conclusion of expiration, the CVP should be measured with the patient resting flat. The catheter’s tip should be at the intersection of the superior vena cava and the right atrium. An electronic transducer is installed and zeroed at the level of the right atrium to measure it (usually in the 4th intercostal space in the mid-axillary line).
CVP is a good predictor of preload in the right ventricle. Hypovolaemia is indicated by a volume challenge of 250-500 mL crystalloid eliciting an increase in CVP that is not sustained for more than 10 minutes.CVP is influenced by a number of factors, including:
Mechanical ventilation (and PEEP)
Pulmonary hypertension
Pulmonary embolism
Heart failure
Pleural effusion
Decreased cardiac output
Cardiac tamponade
CVP is reduced by the following factors:
Distributive shock
Negative pressure ventilation
Hypovolaemia
Deep inhalation -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 59
Incorrect
-
A 74-year-old woman with a history of ischaemic heart disease and heart failure is complaining of worsening oedema, bloating, and a loss of appetite. She has ascites and peripheral oedema on examination. Her oedema is being controlled by an oral diuretic, but it appears that this is no longer enough. You discuss her care with the on-call cardiology registrar, who believes she is very likely to have significant gut oedema that is interfering with her diuretic absorption and that she will need to change her medication.
Which of the following oral diuretics is most likely to help you overcome this problem?Your Answer:
Correct Answer: Bumetanide
Explanation:Bumetanide is primarily used in patients with heart failure who have failed to respond to high doses of furosemide. Bumetanide and furosemide differ primarily in terms of bioavailability and pharmacodynamic potency. In the intestine, furosemide is only partially absorbed, with a bioavailability of 40-50 percent. Bumetanide, on the other hand, is almost completely absorbed in the intestine and has a bioavailability of about 80%. As a result, when it has a better bioavailability than furosemide, it is commonly used in patients with gut oedema.
When taken alone, Bendroflumethiazide is a moderately potent diuretic that is unlikely to control her oedema.
Mannitol is a type of osmotic diuretic used to treat cerebral oedema and high intracranial pressure.
Acetazolamide is a weak diuretic that inhibits carbonic anhydrase. It’s a rare occurrence.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 60
Incorrect
-
Intrinsic factor is vital for gastrointestinal absorption of which of the following:
Your Answer:
Correct Answer: Vitamin B12
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 61
Incorrect
-
Which of the following is not true regarding the structure and function of glomerular filtration membrane?
Your Answer:
Correct Answer: The absence of a basement membrane reduces impedance to filtration
Explanation:The glomerular filtration membrane is composed of fenestrated capillary endothelium, basement membrane, and filtration slits. It is an organized, semipermeable membrane preventing the passage of most of the proteins into the urine.
The anatomical arrangement of the glomerular filtration membrane maximizes the surface area available for filtration. The arrangement of its arterioles results in high hydrostatic pressures and facilitates filtration.
Fenestrated capillary endothelium of the glomerular filtration membrane is with relatively large pores. It allows the free movement of plasma proteins and solutes but still restricts the movement of blood cells.
Filtration slits are the smallest filters and restrict the movement of plasma proteins but still allow free movement of ions and nutrients.
The glomerular basement membrane (GBM) is a critical component of the glomerular filtration membrane. Thus, it is not true that its absence will reduce the resistance of flow. The basement membrane is true to be more selective and contains negatively charged glycoproteins. However, it still allows free passage of water, nutrients, and ions. Severe structural abnormalities of the GBM can result in protein (albumin) leakage.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 62
Incorrect
-
An increased anion gap metabolic acidosis is typically caused by which of the following?
Your Answer:
Correct Answer: Propylene glycol overdose
Explanation:Causes of a raised anion gap acidosis can be remember using the mnemonic MUDPILES:
-Methanol
-Uraemia (in renal failure)
-Diabetic ketoacidosis
-Propylene glycol overdose
-Infection/Iron overdose/Isoniazid/Inborn errors of metabolism
-Lactic acidosis
-Ethylene glycol overdose
-Salicylate overdose -
This question is part of the following fields:
- Physiology
- Renal
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Question 63
Incorrect
-
Cryptococcus neoformans is primarily transmitted by which of the following routes:
Your Answer:
Correct Answer: Inhalation of spores
Explanation:Cryptococcus neoformans is found in bird droppings and transmission is by inhalation of spores, thus the lung is the primary site of infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 64
Incorrect
-
Cardiac muscle and skeletal muscle are alike, but there are a few key variations.
Which of the following is NOT a characteristic of skeletal muscle but is a characteristic of cardiac muscle?ÂYour Answer:
Correct Answer: The presence of intercalated discs
Explanation:Cardiac muscle is striated, and the sarcomere is the contractile unit, similar to skeletal muscle. Contracture is mediated by the interaction of calcium, troponins, and myofilaments, much as it occurs in skeletal muscle. Cardiac muscle, on the other hand, differs from skeletal muscle in a number of ways.
In contrast to skeletal muscle cells, cardiac myocytes have a nucleus in the middle of the cell and sometimes two nuclei. The cells are striated because the thick and thin filaments are arranged in an orderly fashion, although the arrangement is less well-organized than in skeletal muscle.
Intercalated discs, which work similarly to the Z band in skeletal muscle in defining where one cardiac muscle cell joins the next, are a very significant component of cardiac muscle.
Adherens junctions and desmosomes, which are specialized structures that hold the cardiac myocytes together, are formed by the transverse sections. The lateral sections produce gap junctions, which join the cytoplasm of two cells directly, allowing for rapid action potential conduction. These critical properties allow the heart to contract in a coordinated manner, allowing for more efficient blood pumping.
Cardiac myocytes have the ability to create their own action potentials, which is referred to as myogenic’. They can depolarize spontaneously to initiate a cardiac action potential. Pacemaker cells, as well as the sino-atrial (SA) and atrioventricular (AV) nodes, control this.
The Purkinje cells and the cells of the bundle of His are likewise capable of spontaneous depolarization. While the bundle of His is made up of specialized myocytes, it’s vital to remember that Purkinje cells are not myocytes and have distinct characteristics. They are larger than myocytes, with fewer filaments and more gap junctions than myocytes. They conduct action potentials more quickly, allowing the ventricles to contract synchronously.
Cardiac myocytes contract by excitation-contraction coupling, just like skeletal myocytes. Heart myocytes, on the other hand, utilise a calcium-induced calcium release mechanism that is unique to cardiac muscle (CICR). The influx of calcium ions (Ca2+) into the cell causes a ‘calcium spark,’ which causes more ions to be released into the cytoplasm.An influx of sodium ions induces an initial depolarisation, much as it does in skeletal muscle; however, in cardiac muscle, the inflow of Ca2+ sustains the depolarisation, allowing it to remain longer. Due to potassium ion (K+) inflow, CICR causes a plateau phase in which the cells remain depolarized for a short time before repolarizing. Skeletal muscle, on the other hand, repolarizes almost instantly.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 65
Incorrect
-
Many of the chemical digestion and absorption takes place in the small intestine. Most digestive enzymes in the small intestine are secreted by the pancreas and enter the small intestine through the pancreatic duct.
Which of these digestive enzymes is responsible for breaking down carbohydrates into monosaccharides?Your Answer:
Correct Answer: Glucoamylase
Explanation:Majority of carbohydrates are broken down into monosaccharides (glucose, fructose galactose) and are absorbed by the small intestine. Enzymes released from the brush border break down carbohydrate. Some carbohydrates, such as cellulose, are not digested at all, despite being made of multiple glucose units. This is because the cellulose is made out of beta-glucose that makes the inter-monosaccharide bindings different from the ones present in starch, which consists of alpha-glucose. Humans lack the enzyme for splitting the beta-glucose-bond.
The principal brush border enzymes are dextranase and glucoamylase. Other brush border enzymes are maltase, sucrase, and lactase.
Pancreatic amylase breaks down some carbohydrates (notably starch) into oligosaccharides. Dextranase and glucoamylase, then further break down oligosaccharides.
Trypsin aids in digestion of protein.
Chymotrypsin is a proteolytic enzyme that digests protein
Carboxypeptidase hydrolyses the first peptide or amide bond at the carboxyl or C-terminal end of proteins and peptides
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 66
Incorrect
-
The triage nurse asks if you will prescribe a dose of codeine phosphate for a patient who is in a lot of pain. You discover that you are unable to prescribe it due to a contra-indication after evaluating the patient.
The use of codeine phosphate is contraindicated in which of the following situations?Your Answer:
Correct Answer: Age under 12 years
Explanation:Codeine phosphate is a mild opiate that can be used to treat mild to moderate pain when other pain relievers like paracetamol or ibuprofen have failed. It can also be used to treat diarrhoea and coughs that are dry or painful.
The use of all opioids is contraindicated for the following reasons:
Respiratory depression (acute)
Patients who are comatose
Head injury (opioid analgesics impair pupillary responses, which are crucial for neurological evaluation)
Intracranial pressure has risen (opioid analgesics interfere with pupillary responses vital for neurological assessment)
There’s a chance you’ll get paralytic ileus.The use of codeine phosphate is contraindicated in the following situations:
Because of the significant risk of respiratory side effects in children under the age of 12, it is not recommended for children under the age of 12.Patients of any age who have been identified as ultra-rapid codeine metabolizers (CYP2D6 ultra-rapid metabolizers)
Because codeine can pass through breast milk to the baby and because mothers’ ability to metabolise codeine varies greatly, it is especially dangerous in breastfeeding mothers.
If other painkillers, such as paracetamol or ibuprofen, fail to relieve acute moderate pain in children over the age of 12, codeine should be used. In children with obstructive sleep apnoea who received codeine after tonsillectomy or adenoidectomy, a significant risk of serious and life-threatening adverse reactions has been identified.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 67
Incorrect
-
A 60-year-old patient had a sudden onset of palpitations and shortness of breath. He had a history of poorly controlled hypertension and ischemic heart disease. His ECG also shows atrial fibrillation. Based on the patient’s condition, which pharmacologic cardioversion would be best to use?
Your Answer:
Correct Answer: Amiodarone
Explanation:Chemical cardioversion, or pharmacologic cardioversion, is the treatment of abnormal heart rhythms using drugs.
Flecainide and propafenone are examples of drugs used as chemical cardioverters.
However, given the situation of the patient, these drugs are contraindicated for his ischaemic heart disease. Amiodarone is also an antiarrhythmic drug and is the best choice for this situation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 68
Incorrect
-
Which of the following statements is false regarding the biceps brachii muscle?
Your Answer:
Correct Answer: It pronates the radioulnar joint in the forearm
Explanation:The biceps brachii muscle is one of the chief muscles of the arm. The origin at the scapula and the insertion into the radius of the biceps brachii means it can act on both the shoulder joint and the elbow joint, which is why this muscle participates in a few movements of the arm. It derives its name from its two heads which merge in one unique distal body, defining the unusual structure of the muscle.
The biceps brachii muscle is supplied by the musculocutaneous nerve (C5-C6), a branch of the brachial plexus.
Arterial supply to the biceps brachii muscle varies considerably, coming from up to eight vessels originating from the brachial artery in the middle third of the arm.
In the shoulder joint both muscle heads partially enforce opposite movements. The long head pulls the arm away from the trunk (abduction) and turns it inwards (inward rotation) whereas the short head pulls the arm back towards the trunk (adduction). When both heads contract simultaneously it leads to an arm bend (flexion). In the elbow joint the muscle bends the forearm (flexion) and rotates it outwards (supination). The supination is most powerful in a flexed elbow. In addition to the movement functions, the biceps has the important task to support the humeral head within the shoulder joint. Its antagonist is the triceps brachii in the posterior compartment of the arm.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 69
Incorrect
-
Which of the following microbes binds strongly to CD4 antigen:
Your Answer:
Correct Answer: HIV
Explanation:HIV mainly infects CD4+ T helper cells. Viral replication results in progressive T-cell depletion and impaired cell-mediated immunity with subsequent secondary opportunistic infections and increased risk of malignancy. B-cell function is also reduced as a result of lack of T-cell stimulation.
HIV is not a notifiable disease. -
This question is part of the following fields:
- Microbiology
- Principles
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Question 70
Incorrect
-
Regarding hepatitis C, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Anti-HCV IgG antibodies are diagnostic of acute infection.
Explanation:Anti-HCV IgG antibodies indicate exposure to hepatitis C but this could be acute, chronic or resolved infection. If the antibody test is positive, HCV RNA should be tested for, which if positive indicates that a person has current infection with active hepatitis C.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 71
Incorrect
-
Regarding hepatitis A, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Anti-HAV IgM antibodies are diagnostic.
Explanation:Anti-HAV IgM antibodies are diagnostic. Disease in children is more commonly asymptomatic, risk of symptomatic disease increases with age. Transmission is by the faecal-oral route. Faecal shedding has been demonstrated for 2 – 3 weeks before and about a week after, the onset of jaundice. Infection confers lifelong immunity.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 72
Incorrect
-
Regarding diuretics, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Carbonic anhydrase inhibitors have their effect by inhibiting bicarbonate reabsorption.
Explanation:Carbonic anhydrase inhibitors e.g. acetazolamide block the reaction of carbon dioxide and water and so prevent Na+/H+exchange and bicarbonate reabsorption. The increased bicarbonate levels in the filtrate oppose water reabsorption. Proximal tubule sodium reabsorption is also reduced because it is partly dependent on bicarbonate reabsorption.
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This question is part of the following fields:
- Physiology
- Renal
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Question 73
Incorrect
-
The patients listed below have been diagnosed with a variety of ailments.
In which of the following situations would aspirin be an effective treatment option?Your Answer:
Correct Answer: A 36-year-old with an acute migraine (dose of 900-1000 mg)
Explanation:A study published in the Cochrane Database of Systematic Reviews in 2010 found that a single 1000-mg dose of aspirin is effective in treating acute migraine. It was discovered that 24 percent of aspirin users were pain-free after two hours, compared to 11 percent of placebo users. Because the BNF recommends a maximum dose of 900 mg for analgesia and most non-proprietary aspirin comes in a dose of 300 mg, a dose of 900 mg is frequently prescribed in the UK.
Because aspirin is not recommended for children under the age of 16 due to the risk of Reye’s syndrome, it would be inappropriate to give it to the 12-year-old with the viral URTI.
For uncomplicated dental pain, aspirin is an acceptable option, but not for patients who are taking warfarin. The combination of aspirin’s antiplatelet action and warfarin’s anticoagulation properties puts the patient at high risk of bleeding. Furthermore, aspirin can deplete the therapeutic levels of warfarin by displacing it from plasma proteins. It would be better to use another NSAID or analgesic.
In gout, aspirin should be avoided because it reduces urate clearance in the urine and interferes with the action of uricosuric agents. Naproxen, diclofenac, and indomethacin are better options.
Although aspirin is useful for inflammatory pains, the dose of aspirin required for an adequate analgesic effect in severe pain is associated with significant side effects. Naproxen would be a better first-line treatment option.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 74
Incorrect
-
Regarding anaemia, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Anaemia is usually associated with a decrease in red cell 2,3 - DPG.
Explanation:Anaemia is defined as a reduction in haemoglobin concentration below the normal range for the age and sex of the individual. Children tend to have lower haemoglobin than adults, and women tend to have lower haemoglobin than men. Anaemia may occur from an actual reduction in total circulating haemoglobin mass, or with an increase in plasma volume e.g. in pregnancy, causing a dilutional anaemia. After acute major blood loss, anaemia is not immediately apparent because total blood volume is reduced and it takes up to a day for plasma volume to be replaced and hence the degree of anaemia to become apparent. The initial clinical features in acute haemorrhage are therefore a result of reduction in blood volume rather than that of anaemia. When anaemia develops slowly, the associated symptoms are often very mild as the body has time to adapt to the fall in haemoglobin. This involves mechanisms such as an increase in red cell 2,3 -diphosphoglycerate (2,3 – DPG), which shifts the oxygen dissociation curve to the right, allowing enhanced delivery of O2 to the tissues, and an increase in stroke volume and heart rate.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 75
Incorrect
-
In ventricular myocytes, the plateau phase of the action potential comes about through which of the following:
Your Answer:
Correct Answer: Opening of voltage-gated Ca 2+ channels
Explanation:After the intial upstroke of the action potential, Na+channels and currents rapidly inactivate, but in cardiac myocytes, the initial depolarisation activates voltage-gated Ca2+channels (slow L-type channels, threshold approximately – 45 mV) through which Ca2+floods into the cell. The resulting influx of Ca2+prevents the cell from repolarising and causes a plateau phase, that is maintained for about 250 ms until the L-type channels inactivate. The cardiac AP is thus much longer than that in nerve or skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 76
Incorrect
-
The mechanism of action of abciximab is by:
Your Answer:
Correct Answer: Blocking the binding of fibrinogen to GPIIb/IIIa receptor sites
Explanation:Abciximab is a glycoprotein IIb/IIIa inhibitors and prevents platelet aggregation by blocking the binding of fibrinogen to receptors on platelets.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 77
Incorrect
-
A 30-year-old man present to the ED with abdominal pain, nausea and vomiting. It has been present for the past two days.
Which of the following statements regarding diarrhoea and vomiting is true?
Your Answer:
Correct Answer: E.Coli can cause diarrhoea and renal failure
Explanation:Escherichia coli strain 0157 causes enterohaemorrhagic diarrhoea and can lead to renal failure, haemolytic anaemia and thrombocytopenia.
Norwalk virus is an RNA virus.
Although transmission of rotavirus is primarily through the faeco-oral route, airborne spread has been seen in some cases.
Cryptosporidium are protozoa with acid fast walls and are resistant to both chlorine treatment and conventional filtering methods.
There is no therapy effective in treating cryptosporidium diarrhoea as the protozoa is not susceptible to antibiotics.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 78
Incorrect
-
A 58-year-old man with a traumatic brain injury is brought into the ER. A medical student asks you about the processes that occur in the brain following a traumatic injury.
One of these best describes the central nervous systems response to injury.Your Answer:
Correct Answer: Degeneration of the axon occurs proximally before it occurs distally
Explanation:Following neuronal injury, as seen in traumatic brain injury, the axon undergoes anterograde degeneration. Degradation starts from the cell body (proximally) and progresses distally. The axon becomes fragmented and degenerates.
The brain shows no reactive changes to injury is incorrect. Following major injury such as stroke, the brain undergoes a process of liquefactive degeneration, which leaves cystic spaces within the brain.
Axonal regeneration does not occur to any significant extent within the central nervous system unlike what is seen in the peripheral nervous system.
Astrocytes undergo reactive gliosis, leaving behind a firm translucent tissue around sites of damage.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 79
Incorrect
-
Regarding water and electrolyte absorption in the small intestine, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Na+ enters the cell across the apical membrane against its concentration gradient by both membrane channels and transporter protein mechanisms.
Explanation:As the contents of the intestine are isotonic with body fluids and mostly have the same concentration of the major electrolytes, their absorption is active. Water cannot be moved directly, but follows osmotic gradients set up by the transport of ions, primarily mediated by the sodium pump.Na+/K+ ATPase located on the basolateral membrane of the epithelial cells pumps three Na+ ions from the cell in exchange for two K+ ions, against their respective concentration gradients. This leads to a low intracellular concentration of Na+ and a high intracellular concentration of K+. The low intracellular concentration of Na+ ensures a movement of Na+ from the intestinal contents into the cell down its concentration gradient by both membrane channels and transporter protein mechanisms. Na+ is then rapidly pumped again by the basolateral sodium pump. K+ leaves the cell across the basolateral membrane down its concentration gradient linked to an outward movement of Cl- against its concentration gradient (Cl- having entered the cell across the luminal membrane down its concentration gradient).
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 80
Incorrect
-
Regarding renal clearance, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The MDRD equation uses plasma creatinine to estimate the GFR making an adjustment for age, sex and race.
Explanation:Clearance is defined as the volume of plasma that is cleared of a substance per unit time. Inulin clearance is the gold standard for measurement of GFR but creatinine clearance is typically used instead. Creatinine is freely filtered and not reabsorbed, but there is a little creatinine tubular secretion. In practice, GFR is usually estimated from the plasma creatinine using a formula e.g. the MDRD equation making an adjustment for age, sex and race.
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This question is part of the following fields:
- Physiology
- Renal
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Question 81
Incorrect
-
A 28-year-old medical student ate a reheated Chinese takeaway and developed severe vomiting a few hours after.
What is the SINGLE MOST likely causative organism?
Your Answer:
Correct Answer: Bacillus cereus
Explanation:Bacillus cereusis is the correct answer. It is a Gram-positive, rod-shaped, beta-haemolytic bacterium that causes ‘fried rice syndrome’.
Hardy spores in rice can survive boiling. When left at room temperature for long periods prior to frying these spores germinate. The emetic enterotoxin-producing strains cause nausea and vomiting between 1 and 6 hours after consumption while the diarrheagenic enterotoxin-producing strains (commonly associated with ingestion of meat, vegetables and dairy products) causes abdominal pain and vomiting, which starts 8-12 hours after ingestion.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 82
Incorrect
-
A 5-year-old girl is brought into the Paediatric ER for acute seizures. She has been convulsing for the past 18 minutes now and was already two doses of lorazepam in the ambulance. Now, you prepare a phenytoin infusion to abolish the seizures.
According to the APLS algorithm, what dose of phenytoin is advised for a convulsing child at this stage?Your Answer:
Correct Answer: 20 mg/kg over 20 minutes
Explanation:Advanced paediatric life support (APLS) recommends phenytoin as the first choice for second-line anticonvulsant in a patient that continues to seize ten minutes after the second dose of the first-line anticonvulsant (benzodiazepine). (step 3 of the APLS algorithm)
The recommended dose of phenytoin infusion is up at 20 mg/kg over 20 minutes. If the patient has already taken phenytoin as maintenance therapy or is allergic to phenytoin, then a phenobarbitone infusion should be set up at 20 mg/kg over 30-60 minutes.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 83
Incorrect
-
When an elderly dehydrated patient is moved from a supine to a standing position, her heart rate increases. Which of the following accounts for the increase in heart rate upon standing:
Your Answer:
Correct Answer: Decreased venous return
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 84
Incorrect
-
Salivary glands produce saliva which is mostly water, but it also contains a range of essential chemicals such as mucus, electrolytes, antibiotic agents, and enzymes.
Which of the following is a carbohydrate-digesting enzyme found in saliva?
Your Answer:
Correct Answer: Amylase
Explanation:The acinar cells of the parotid and submandibular glands release amylase. Amylase begins starch digestion before food is even eaten, and it works best at a pH of 7.4.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 85
Incorrect
-
A newborn baby is born by vaginal delivery to a mother who has a Chlamydia infection and who is started on treatment after the delivery. The neonate subsequently develops an infection also.
Which one of these is the most common neonatal manifestation of Chlamydia trachomatis infection?Your Answer:
Correct Answer: Conjunctivitis
Explanation:Conjunctivitis is the most common neonatal manifestation of Chlamydia trachomatis infection. The second commonest neonatal manifestation is pneumonia
Ophthalmia neonatorum refers to any conjunctivitis in the newborn period, irrespective of causative organism. Presently, chlamydia is the single most common cause, accounting for up to 40% of cases. Ophthalmia neonatorum caused by chlamydia typically presents 5 to 14 days after birth with unilateral or bilateral watery discharge that progressively becomes more copious and purulent. There is no associated risk of ulceration and perforation, and the eyes are less inflamed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 86
Incorrect
-
Gastric emptying is increased by all of the following EXCEPT for:
Your Answer:
Correct Answer: Secretin
Explanation:Gastric emptying is increased by:
Distension of the pyloric antrum
A fall in the pH of chyme in the stomach
Parasympathetic stimulation (via vagus)
Gastrin
The hormones secretin, cholecystokinin and gastric inhibitory polypeptide (GIP) inhibit gastric emptying. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 87
Incorrect
-
A 58-year-old man presented to the emergency room complaining of a chest pain that has been going on for the past 12 hours. Upon further investigation, a troponin test was ordered and the results came back negative. He was given a discharge order from the emergency department.
Which of the following aspects of this test is considered the most significant in the decision made that it was safe to send the patient home?Your Answer:
Correct Answer: Likelihood ratio
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.
A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 88
Incorrect
-
An analytical study is conducted to compare the risk of stroke between Ticagrelor therapy and Warfarin therapy among patients with atrial fibrillation. The following is obtained from the study:
No. of patients who took Ticagrelor: 300
No. of patients who took Ticagrelor and suffered a stroke: 30
No. of patients who took Warfarin: 500
No. of patients who took Warfarin and suffered a stroke: 20
Compute for the absolute risk reduction of a stroke, with Warfarin as the standard of treatment.Your Answer:
Correct Answer: -0.06
Explanation:Absolute risk reduction (ARR) is computed as the difference between the absolute risk in the control group (ARC) and the absolute risk in the treatment group (ART).
Since Warfarin is the standard of treatment, Warfarin is considered as the control group.
ARR = ARC-ART
ARR = (20/500) – (30/300)
ARR = -0.06This means that there is increased risk of stroke in the treatment group, which is the Ticagrelor group.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 89
Incorrect
-
A 61-year-old patient experiences a spontaneous rupture of his Achilles tendon following a course of antibiotics
Which of the antibiotics listed below is MOSTÂ likely to be the cause?ÂYour Answer:
Correct Answer: Ciprofloxacin
Explanation:Tendinopathy and spontaneous tendon rupture are caused by fluoroquinolones, which are an uncommon but well-known cause. Tendon problems caused by fluoroquinolones are expected to affect 15 to 20 people per 100,000. Patients over the age of 60 are most likely to develop them.
It usually affects the Achilles tendon, but it has also been described in cases involving the quadriceps, peroneus brevis, extensor pollicis longus, long head of biceps brachii, and rotator cuff tendons. The exact aetiology is uncertain, although the fluoroquinolone medication is thought to obstruct collagen activity and/or cut off blood supply to the tendon.
Other factors linked to tendon rupture spontaneously include:
Gout
Treatment with corticosteroids
Hypercholesterolaemia
Long-term dialysis
Kidney transplant
Rheumatoid arthritis -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 90
Incorrect
-
Which of the following data types does a pain-scoring system represent?
Your Answer:
Correct Answer: Ordinal
Explanation:Pain scoring systems are processes for assessing pain and the severity of illnesses that have been scientifically designed and tested. An example of ordinal categorical data is a pain scoring system.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 91
Incorrect
-
Which of the following presentations is NOT consistent with the diagnosis of anaphylaxis following exposure to a known allergen:
Your Answer:
Correct Answer: Generalised urticaria and angioedema alone
Explanation:Anaphylaxis is characterised by sudden onset and rapidly developing, life-threatening airway, breathing and circulation problems associated with skin and/or mucosal changes. Reactions can vary greatly, from hypotension alone, to reactions with predominantly asthmatic features, to cardiac/respiratory arrest. Skin or mucosal changes may be absent or subtle in up to 20% of cases but skin or mucosal changes alone are not a sign of an anaphylactic reaction.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 92
Incorrect
-
A 66-year-old female presents to the Emergency Department with a nose bleed. She says that she has been having frequent episodes of nose bleeds over the past four months, along with increasing fatigue and some weight loss. On examination, she has a diffuse petechial rash and hypertrophy of the gingiva.
Which one of the following conditions is this patient most likely to have?Your Answer:
Correct Answer: Acute myeloid leukaemia (AML)
Explanation:The history of nosebleeds and fatigue, and gingival hyperplasia presents a typical picture of acute myeloid leukaemia. Leukemic infiltrates within the gingiva cause hypertrophy and distinguish this condition from other types of leukaemia. The fatigue is secondary to anaemia, while the nosebleeds are caused by thrombocytopenia secondary to leukemic infiltration of bone marrow. Patients may also report frequent infections secondary to neutropenia and hepatosplenomegaly.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 93
Incorrect
-
Fracture of the medial epicondyle would result to the following, except
Your Answer:
Correct Answer: Weakness of abduction of the thumb
Explanation:Thumb abduction is mediated by the abductor pollicis longus and brevis, which are innervated by the radial and median nerves, respectively.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 94
Incorrect
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A 35-year-old man is feeling unwell following his return from a business trip. He is diagnosed with a vector transmitted disease.
Which of these organisms is commonly spread by vector-borne transmission?Your Answer:
Correct Answer: Borrelia burgdorferi
Explanation:Borrelia burgdorferiis, primarily spread by ticks and lice, is a zoonotic, vector-borne organism that causes Lyme disease.
Neisseria meningitidis and Bordetella pertussis are droplet borne infections (airborne particle > 5 µm)
Vibrio cholerae and Ascaris lumbricoides are spread by the faeco-oral route
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 95
Incorrect
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Which of the following side effects is most likely caused by erythromycin:
Your Answer:
Correct Answer: QT - prolongation
Explanation:The side effects of erythromycin include abdominal pain, anaphylaxis,
cholestatic hepatitis, confusion,
diarrhoea, dyspepsia, fever, flatulence, hallucinations, hearing loss,
headache, hypertrophic pyloric stenosis, hypotension, Interstitial
nephritis, mild allergic reactions, nausea, nervous system effects,
including seizures, pain, pruritus, pseudomembranous colitis,
QT prolongation, rash, skin eruptions, tinnitus, urticaria,
ventricular arrhythmias, ventricular tachycardia, vertigo, vomiting -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 96
Incorrect
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Intravenous glucose solutions are typically used in the treatment of all of the following situations except:
Your Answer:
Correct Answer: Hypokalaemia
Explanation:In hypokalaemia, initial potassium replacement therapy should not involve glucose infusions, as glucose may cause a further decrease in the plasma-potassium concentration. Glucose infusions are used for the other indications like diabetic ketoacidosis, hypoglycaemia, routine fluid maintenance in patients who are nil by mouth (very important in children), and in hyperkalaemia.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 97
Incorrect
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A foot drop is a sign of damage to which of the following nerves?
Your Answer:
Correct Answer: Deep fibular nerve
Explanation:The deep fibular nerve was previously referred to as the anterior tibial nerve.
It starts at the common fibular nerve bifurcation, between the fibula and the proximal part of the fibularis longus. Damage to this nerve can cause foot drop or loss of dorsiflexion since this nerve controls the anterior leg muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 98
Incorrect
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The role of the juxtaglomerular (granular) cells of the juxtaglomerular apparatus is:
Your Answer:
Correct Answer: Production of renin
Explanation:Juxtaglomerular cells synthesise renin. These cells are specialised smooth muscle cells that are located in the walls of the afferent arterioles, and there are some in the efferent arterioles.
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This question is part of the following fields:
- Physiology
- Renal
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Question 99
Incorrect
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One of your patients is in resuscitation and is suffering from kidney failure. The intensive care outreach team arrives to assess them and determines that a dopamine infusion is necessary.
Dopamine primarily acts on which of the following receptors at low doses?Your Answer:
Correct Answer: Dopamine receptors
Explanation:Dopamine is a catecholamine that occurs naturally and is used to treat low cardiac output, septic shock, and renal failure. It is both adrenaline and noradrenaline’s immediate precursor.
Dopamine acts on D1 and D2 dopamine receptors in the renal, mesenteric, and coronary beds at low doses (1-5 g/kg/min). Dopamine causes a significant decrease in renal vascular resistance and an increase in renal blood flow at these doses. Within this dose range, it is also involved in central modulation of behaviour and movement.
Dopamine stimulates beta- and alpha-adrenergic receptors directly and indirectly at higher doses. Beta-stimulation predominates at a rate of 5-10 g/kg/min, resulting in a positive inotropic effect that increases cardiac output and coronary blood flow. Alpha-stimulation predominates at infusion rates greater than 15 g/kg/min, resulting in peripheral vasoconstriction and an increase in venous return and systolic blood pressure.
Below is a summary of the mechanisms and effects of various inotropic agents:
Inotrope
Mechanism
Effects
Adrenaline (epinephrine)
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Noradrenaline (norepinephrine)
Mainly alpha-agonist;
Beta-1 and -2 agonist at increasing doses
Vasoconstriction;
Some increased cardiac output
Dopamine
Dopamine agonist at low doses;
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Dobutamine
Mainly beta-1 agonist
Increased cardiac output -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 100
Incorrect
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The sensory innervation of the oropharynx is provided by which of the following nerves:
Your Answer:
Correct Answer: Glossopharyngeal nerve
Explanation:Each subdivision of the pharynx has a different sensory innervation:the nasopharynx is innervated by the maxillary nervethe oropharynx is innervated by the glossopharyngeal nervethe laryngopharynx is innervated by the vagus nerve.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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SESSION STATS - PERFORMANCE PER SPECIALTY
