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Question 1
Incorrect
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Reed-Sternberg cells are characteristic of which of the following malignancies:
Your Answer: Multiple Myeloma
Correct Answer: Hodgkin lymphoma
Explanation:Lymphomas are a group of diseases caused by malignant lymphocytes that accumulate in lymph nodes and other lymphoid tissue and cause the characteristic clinical feature of lymphadenopathy. The major subdivision of lymphomas is into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) and this is based on the histological presence of Reed-Sternberg cells present in HL. Hodgkin lymphoma can present at any age but is rare in children and has a peak incidence in young adults. There is an almost 2 : 1 male predominance. Most patients present with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes. Cervical nodes are involved in 60-70% of cases, axillary nodes in 10-15% and inguinal nodes in 6-12%. Modest splenomegaly occurs during the course of the disease in 50% of patients; the liver may also be enlarged. Bone marrow failure involvement is unusual in early disease. The prognosis depends on age, stage and histology, but overall approximately 85% of patients are cured. Alcohol‐induced pain and pruritus are two well‐known but rare symptoms in HL.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 2
Incorrect
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Chronic myeloid leukaemia is most common in middle-aged and elderly people. It is responsible for 20% of all leukemias.
Which of the following statements about CML is NOT TRUE?Your Answer: It can be treated with tyrosine kinase inhibitors
Correct Answer: Serum B12 is typically low
Explanation:Chronic myeloid leukaemia is most common in middle-aged and elderly people. It is responsible for 20% of all leukemias. The majority of CML patients experience fatigue, weight loss, and excessive sweating.
The Philadelphia chromosome is found in over 90% of CML cases. A balanced translocation between chromosomes 9 and 22 is known as the Philadelphia chromosome.
Because white cells produce a B12 binding protein, serum B12 levels in CML are typically high.
In CML, the neutrophil alkaline phosphatase score is usually low.
Almost all patients with CML eventually progress to blast crisis, though this can take up to ten years. If any of the following features are present in a CML patient, a blast crisis is diagnosed:
In the blood or bone marrow, there are more than 20% myeloblasts or lymphoblasts.
On a bone marrow biopsy, large clusters of blasts were discovered.CML can be treated with tyrosine kinase inhibitors like imatinib and dasatinib if a chloroma (a solid tumour made up of myeloblasts that grows outside of the bone marrow) is present.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 3
Correct
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Intravenous glucose solutions are typically used in the treatment of all of the following situations except:
Your 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 4
Correct
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A 65-year-old man presents with a red, hot, swollen great toe. A diagnosis of acute gout is made. His past medical history includes heart failure and type 2 diabetes mellitus.
Which of the following is the most appropriate medication to use in the treatment of his gout? Select ONE answer only.Your Answer: Colchicine
Explanation:In the absence of any contra-indications, high-dose NSAIDs are the first-line treatment for acute gout. Naproxen 750 mg as a stat dose followed by 250 mg TDS is a commonly used and effective regime.
Aspirin should not be used in gout as it reduces the urinary clearance of urate and interferes with the action of uricosuric agents. Naproxen, Diclofenac or Indomethacin are more appropriate choices.
Allopurinol is used prophylactically, preventing future attacks by reducing serum uric acid levels. It should not be started in the acute phase as it increases the severity and duration of symptoms.
Colchicine acts on the neutrophils, binding to tubulin to prevent neutrophil migration into the joint. It is as effective as NSAIDs in relieving acute attacks. It also has a role in prophylactic treatment if Allopurinol is not tolerated.
NSAIDs are contra-indicated in heart failure as they can cause fluid retention and congestive cardiac failure. Colchicine is the preferred treatment in patients with heart failure or those who are intolerant of NSAIDs. -
This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 5
Incorrect
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Compression of this nerve can cause weakness in the left leg while walking and thigh adduction weakness at the hip joint.
Your Answer: Sciatic nerve
Correct Answer: Obturator nerve
Explanation:The obturator nerve is a sensory and motor nerve that emerges from the lumbar plexus and innervates the thigh.
This nerve supplies motor innervation to the medial compartment of the thigh, making it necessary for thigh adduction.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 6
Correct
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An elderly man with chronic heart and lung disease develops Legionnaires' Disease. By what route was the infection most likely to have been acquired:
Your Answer: Inhalation of aerosolised contaminated water
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.
The clinical features of the pneumonic form of Legionnaires’ disease include:
Mild flu-like prodrome for 1-3 days
Cough (usually non-productive and occurs in approximately 90%)
Pleuritic chest pain
Haemoptysis
Headache
Nausea, vomiting and diarrhoea
Anorexia
Legionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.
Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.
Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease. -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 7
Incorrect
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The monospot test for infectious mononucleosis uses which of the following types of red blood cell?
Your Answer: Pig red blood cells
Correct Answer: Horse red blood cells
Explanation:Infectious mononucleosis can be diagnosed using specific EBV antibodies and a variety if unrelated non-EBV heterophile antibodies. These antibodies can be detected by two main screening tests:
The monospot test uses horse red blood cells. It agglutinates in the presence of heterophile antibodies.
Sheep red blood cells is used in Paul-Bunnell test. The blood agglutinates in the presence of heterophile antibodies.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 8
Correct
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Antispasmodic drugs are primarily indicated in which of the following conditions:
Your Answer: Irritable bowel syndrome
Explanation:Antispasmodics, such as antimuscarinics, may be used in the management of irritable bowel syndrome. Other antispasmodics used include direct-acting smooth muscle relaxants such as mebeverine, alverine, and peppermint oil. Antispasmodics are contraindicated in bowel obstruction and severe inflammatory bowel disease. Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects. Antimuscarinics are contraindicated in urinary retention.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 9
Correct
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Which of the following drug classes may cause bronchoconstriction:
Your Answer: Beta-blockers
Explanation:Beta-blockers, including those considered to be cardioselective, should usually be avoided in patients with a history of asthma, bronchospasm or a history of obstructive airways disease. However, when there is no alternative, a cardioselective beta-blocker can be given to these patients with caution and under specialist supervision. In such cases the risk of inducing bronchospasm should be appreciated and appropriate precautions taken.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 10
Incorrect
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Which of the following laboratory findings is NOT typical of Hodgkin lymphoma:
Your Answer: Neutrophilia
Correct Answer: Basophilia
Explanation:Features may include:Normochromic normocytic anaemia is most common; bone marrow failure involvement is unusual in early disease, but if it occurs bone marrow failure may develop with leucoerythroblastic anaemiaOne-third of patients have a neutrophilia; eosinophilia is frequentAdvanced disease is associated with lymphopenia and loss of cell-mediated immunityPlatelet count is normal or increased in early disease and reduced in later stagesESR and CRP are usually raised (ESR is useful in monitoring disease progress)Serum LDH is raised initially in 30-40% of casesDiagnosis is made by histological examination of an excised lymph nodeThe distinctive multinucleate polypoid RS cell is central to the diagnosis of the four classic types of HL (95% of cases)
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This question is part of the following fields:
- Haematology
- Pathology
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Question 11
Correct
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A 30-year-old woman is transfused following a diagnosis of anaemia secondary to heavy vaginal bleeding. She complains of feeling hot and cold during transfusion of the second unit and her temperature is 38.5ºC. Prior to the transfusion, her temperature was 37ºC. She has no other symptoms.
Which of these transfusions reactions most likely occurred?Your Answer: Febrile transfusion reaction
Explanation:Febrile transfusion reactions presents with an unexpected temperature rise (≥ 38ºC or ≥ 1ºC above baseline, if baseline ≥ 37ºC) during or shortly after transfusion. It is usually an isolated finding and the fever is accompanied by chills and malaise occasionally.
Allergic reaction is commonly caused by foreign plasma proteins but may be due to anti-IgA. Allergic type reactions usually present with urticaria, pruritus, hives. Associations include laryngeal oedema or bronchospasm.
Acute haemolytic reaction aka immediate haemolytic transfusion reaction presents with fever, chills, pain at transfusion site, nausea, vomiting, dark urine and feeling of ‘impending doom’. Often, it occurs due to ABO incompatibility.
Transfusion-associated circulatory overload (TACO) presents as acute or worsening respiratory distress within 6 hours of transfusion of a large volume of blood. It is common in patients with diminished cardiac reserve or chronic anaemia. Elderly patients, infants and severely anaemic patients are particularly susceptible. Clinical features of TACO include: Acute respiratory distress, Tachycardia, Hypertension, Acute/worsening pulmonary oedema on chest X-ray. The BNP is usually raised to at least 1.5 times the pre-transfusion baseline.
Transfusion-related lung injury (TRALI) is a form of acute respiratory distress caused by the donor plasma containing antibodies against the patient’s leukocytes. It is defined as hypoxia and bilateral pulmonary oedema that occurs within 6 hours of a transfusion in the absence of other causes of acute lung injury. Clinical features include Breathlessness, cough, frothy sputum, hypertension or hypotension, hypoxia and fever. Chest X-ray shows multiple perihilar nodules with infiltration of the lower lung fields.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 12
Correct
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A 62-year-old woman presents with cold sensitivity, tiredness, and weight gain. A series of blood tests done shows a grossly elevated TSH level and a diagnosis of hypothyroidism is made.
What is the commonest cause of hypothyroidism worldwide?Your Answer: Iodine deficiency
Explanation:Hypothyroidism occurs when there is a deficiency of circulating thyroid hormones. It is commoner in women and is most frequently seen in the age over 60.
Iodine deficiency is the commonest cause of hypothyroidism worldwide.
In developed countries, iodine deficiency is not a problem and autoimmune thyroiditis is the commonest cause.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 13
Correct
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Which of the following is NOT a typical feature of benzodiazepine toxicity:
Your Answer: Hyperventilation
Explanation:Features of benzodiazepine toxicity include: drowsiness, ataxia, dysarthria, nystagmus, occasionally respiratory depression and coma
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 14
Correct
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Following the administration of a drug that was started a few months earlier, a patient presents with features of peripheral neuropathy.
Which of the following drugs is most likely to cause peripheral neuropathy?
Your Answer: Isoniazid
Explanation:Isoniazid, a first-line agent for the treatment of tuberculosis, has the commonest side effect of peripheral neuropathy. It occurs in up to 20% of patients taking the drug at a dose > 6 mg/kg daily.
Isoniazid combines with pyridoxine (vitamin B6) to form hydrazone, which is excreted in the urine. This causes a deficiency of biologically active pyridoxine leading to peripheral neuropathy.
Peripheral neuropathy of isoniazid is prevented by the co-administration of pyridoxine at a dose of 10 mg for each 100 mg of isoniazid given.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 15
Incorrect
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If a patient dislocated his right shoulder and has been referred to the orthopaedic outpatient department for a follow-up after a successful reduction, which of the following is the most important position for him to avoid holding his arm in until he is seen in the clinic?
Your Answer: Arm held flexed across abdomen palm up
Correct Answer: Arm at 90 degrees to side with palm up
Explanation:The arm should be placed in a poly-sling that should be worn for about two weeks. A physiotherapist may give gentle movements for the arm to help in reducing stiffness and in relieving the pain. It is important that the patient must avoid positions that could cause re-dislocation.
The most important position to avoid is the arm being held out at 90 degrees to the side with the palm facing upwards, especially if a force is being applied. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 16
Incorrect
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Regarding box and whisker plots, which of the following statements is true?
Your Answer: The box represents 25% of the data
Correct Answer: 25% of the values lie below the lower quartile
Explanation:A box and whisker plot is defined as a graphical method of displaying variation in a set of data. In most cases, a histogram analysis provides a sufficient display, but a box and whisker plot can provide additional detail while allowing multiple sets of data to be displayed in the same graph.
The procedure to develop a box and whisker plot comes from the five statistics below:
(1) Minimum value: The smallest value in the data set
(2) Second quartile: The value below which the lower 25% of the data are contained
(3) Median value: The middle number in a range of numbers
(4) Third quartile: The value above which the upper 25% of the data are contained
(5) Maximum value: The largest value in the data set
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This question is part of the following fields:
- Evidence Based Medicine
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Question 17
Correct
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A 67-year-old woman arrives at the Emergency Department with chest pain. Flecainide is one of the medications she is taking.
Which of the following statements about flecainide mechanism of action is correct?Your Answer: Blocks Na+ channels in the heart
Explanation:Flecainide is an antiarrhythmic drug of class Ic that works by blocking the Nav1.5 sodium channel in the heart, prolonging the cardiac action potential and slowing cardiac impulse conduction. It has a significant impact on accessory pathway conduction, particularly retrograde conduction, and significantly reduces ventricular ectopic foci.
Many different arrhythmias can be treated with flecainide, including:
Pre-excitation syndromes (e.g. Wolff-Parkinson-White)
Acute atrial arrhythmias
Ventricular arrhythmias
Chronic neuropathic painThe use of flecainide is contraindicated in the following situations:
Abnormal left ventricular function
Atrial conduction defects (unless pacing rescue available)
Bundle branch block (unless pacing rescue available)
Distal block (unless pacing rescue available)
Haemodynamically significant valvular heart disease
Heart failure
History of myocardial infarction
Long-standing atrial fibrillation where conversion to sinus rhythm not attempted
Second-degree or greater AV block (unless pacing rescue available)
Sinus node dysfunction (unless pacing rescue available)Flecainide should only be used in people who don’t have a structural heart problem. The CAST trial found a significant increase in sudden cardiac death and all-cause mortality in patients with an ejection fraction of less than 40% after a myocardial infarction, where it tended to be pro-arrhythmic.
Anti-arrhythmic drugs have a limited and ineffective role in the treatment of atrial flutter. It’s important to keep in mind that flecainide shouldn’t be used by itself to treat atrial flutter. When used alone, there is a risk of inducing 1:1 atrioventricular conduction, which results in an increase in ventricular rate that is paradoxical. As a result, it should be used in conjunction with a beta-blocker or a calcium channel blocker with a rate-limiting effect.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 18
Incorrect
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A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle weakness and headaches. She is known to be hypertensive and takes amlodipine to control this. Her blood results today show that her potassium level is low at 3.0 mmol/L, and her sodium level is slightly elevated at 146 mmol/L.
Which of the following is the SINGLE most appropriate INITIAL investigation?Your Answer: Random cortisol level
Correct Answer: Plasma renin and aldosterone levels
Explanation:Primary hyperaldosteronism occurs when there are excessive levels of aldosterone independent of the renin-angiotensin axis. Secondary hyperaldosteronism occurs due to high renin levels.
The causes of primary hyperaldosteronism include:
Adrenal adenoma (Conn’s syndrome) – the most common cause of hyperaldosteronism (,80% of all cases). These are usually unilateral and solitary and are more common in women.
Adrenal hyperplasia – this accounts for ,15% of all cases. Usually, bilateral adrenal hyperplasia (BAH) but can be unilateral rarely. More common in men than women.
Adrenal cancer – a rare diagnosis but essential not to miss
Familial aldosteronism – a rare group of inherited conditions affecting the adrenal glands
The causes of secondary hyperaldosteronism include:
Drugs – diuretics
Obstructive renal artery disease – renal artery stenosis and atheroma
Renal vasoconstriction – occurs in accelerated hypertension
Oedematous disorders – heart failure, cirrhosis and nephrotic syndrome
Patients are often asymptomatic. When clinical features are present, the classically described presentation of hyperaldosteronism is with:
Hypertension
Hypokalaemia
Metabolic alkalosis
Sodium levels can be normal or slightly raised
Other, less common, clinical features include:
Lethargy
Headaches
Muscle weakness (from persistent hypokalaemia)
Polyuria and polydipsia
Intermittent paraesthesia
Tetany and paralysis (rare)
Often the earliest sign of hyperaldosteronism is from aberrant urea and electrolytes showing hypokalaemia and mild hypernatraemia. If the patient is taking diuretics, and the diagnosis is suspected, these should be repeated after the patient has taken off diuretics.
If the diagnosis is suspected, plasma renin and aldosterone levels should be checked. Low renin and high aldosterone levels (with a raised aldosterone: renin ratio) is suggestive of primary aldosteronism.
If the renin: aldosterone ratio is high, then the effect of posture on renin, aldosterone and cortisol can be investigated to provide further information about the underlying cause of primary hyperaldosteronism. Levels should be measured lying at 9 am and standing at noon:
If aldosterone and cortisol levels fall on standing, this is suggestive of an ACTH dependent cause, e.g. adrenal adenoma (Conn’s syndrome)
If aldosterone levels rise and cortisol levels fall on standing, this is suggestive of an angiotensin-II dependent cause, e.g. BAH
Other investigations that can help to distinguish between an adrenal adenoma and adrenal hyperplasia include:
CT scan
MRI scan
Selective adrenal venous sampling -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 19
Incorrect
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The term cardiac output refers to the amount of blood pumped by the heart in one minute. The rate in women is around 5 L/min, whereas in men is somewhat higher, around 5.5 L/min.
Which of the equations below best describes cardiac output?
Your Answer: Stroke volume / total peripheral resistance
Correct Answer: Stroke volume x heart rate
Explanation:Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR):
CO = HR x SVAs a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 20
Incorrect
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A patient presents with a laceration on his hand and wrist that has cut the nerve that innervates opponens pollicis.
The opponens pollicis muscle is innervated by which of the following nerves? Select ONE answer only.Your Answer: The palmar digital branch of the median nerve
Correct Answer: The recurrent branch of the median nerve
Explanation:Opponens pollicis is a small, triangular muscle that forms part of the thenar eminence. It originates from the flexor retinaculum and the tubercle of trapezium bone and inserts into the whole length of the first metacarpal bone on its radial side.
Opponens pollicis is innervated by the recurrent branch of the median nerve and receives its blood supply from the superficial palmar arch.
The main action of opponens pollicis is to flex the first metacarpal bone at the carpometacarpal joint, which opposes the thumb towards the centre of the palm. It also medially rotates the first metacarpal bone at the carpometacarpal joint. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 21
Incorrect
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A 32-year-old asthmatic patient on theophylline as part of her asthma management presents to the Emergency Department with an unrelated medical condition.
Which of these drugs should be avoided?Your Answer: Amitriptyline
Correct Answer: Clarithromycin
Explanation:Macrolide antibiotics (e.g. clarithromycin and erythromycin) are cytochrome P450 enzyme inhibitors. They increase blood levels of theophylline leading to hypokalaemia, and potentially increasing the risk of Torsades de pointes when they are prescribed together.
Co-prescription with theophylline should be avoided.
Factors that enhance theophylline clearance include cigarette smoking, carbamazepine, phenobarbital, phenytoin, primidone, and rifampin.
Medications that inhibit clearance include ethanol, ciprofloxacin, erythromycin, verapamil, propranolol, ticlopidine, tacrine, allopurinol, and cimetidine. -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 22
Incorrect
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A patient in the Emergency Department had a diagnosis of diabetic ketoacidosis (DKA) and you commence an insulin infusion. Which of these statements concerning endogenous insulin is true?
Your Answer: Glucagon inhibits insulin release
Correct Answer: Insulin has a short half-life of around 5-10 minutes
Explanation:Insulin, a peptide hormone, is produced in the pancreas by the beta-cells of the islets of Langerhans.
The beta-cells first synthesise an inactive precursor called preproinsulin which is converted to proinsulin by signal peptidases, which remove a signal peptide from the N-terminus.
Proinsulin is converted to insulin by the removal of the C-peptide.
Insulin has a short half-life in the circulation of about 5-10 minutes.
Glucagon and parasympathetic stimulation stimulates insulin release. -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 23
Incorrect
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A 30-year old male is taken to the emergency room after suffering a blunt trauma to the abdomen. He is complaining of severe abdominal pain, however all his other vital signs remain stable. A FAST scan is performed to assess for hemoperitoneum.
If hemoperitoneum is present, it is most likely to be observed in which of the following areas?Your Answer: Para-colic
Correct Answer: Liver
Explanation:The Focused Assessment with Sonography in Trauma (FAST) is an ultrasound protocol developed to assess for hemoperitoneum and hemopericardium. Numerous studies have demonstrated sensitivities between 85% to 96% and specificities exceeding 98%.
The FAST exam evaluates four regions for pathologic fluid: (1) the right upper quadrant, (2) the subxiphoid (or subcostal) view, (3) the left upper quadrant, and (4) the suprapubic region.
The right upper quadrant (RUQ) visualizes the hepatorenal recess, also known as Morrison’s pouch, the right paracolic gutter, the hepato-diaphragmatic area, and the caudal edge of the left liver lobe. The probe is positioned in the sagittal orientation along the patient’s flank at the level of the 8 to 11 rib spaces. The hand is placed against the bed to ensure visualization of the retroperitoneal kidney. The RUQ view is the most likely to detect free fluid with an overall sensitivity of 66%. Recent retrospective evidence suggests the area along the caudal edge of the left lobe of the liver has the highest sensitivity, exceeding 93%.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 24
Incorrect
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A 64-year-old woman had a humerus midshaft fracture due to tripping on a curb and falling on her left arm. She might also have damaged which of the following structures?
Your Answer: Axillary nerve and posterior humeral circumflex artery
Correct Answer: Radial nerve and deep brachial artery
Explanation:The radial nerve and brachial artery are most likely to be damaged in humerus fractures. They are tethered together to the bone and cannot withstand the forces applied to it as a result of the displacement.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 25
Incorrect
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In relaxation, Ca 2+ is transported out of the cell using energy from a Na + gradient.
Explanation:During the AP plateau, Ca2+enters the cell and activates Ca2+sensitive Ca2+release channels in the sarcoplasmic reticulum allowing stored Ca2+to flood into the cytosol; this is called Ca2+-induced Ca2+release. In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane which pumps one Ca2+ion out in exchange for three Na+ions in, using the Na+electrochemical gradient as an energy source. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Factors that affect intracellular [Ca2+] and hence cardiac contractility are called inotropes.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 26
Incorrect
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Regarding the refractory period, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Action potentials can occur in the relative refractory period but the amplitude of the action potential is smaller.
Explanation:Following the action potential, Na+channels remain inactive for a time in a period known as the absolute refractory period where they cannot be opened by any amount of depolarisation. Following this there is a relative refractory period where the temporary hyperpolarisation (due to delayed closure of rectifier K+channels) makes the cell more difficult to depolarise and an action potential can be generated only in response to a larger than normal stimulus. The refractory period limits the frequency at which action potentials can be generated, and ensures that, once initiated, an action potential can travel only in one direction. An action potential is an all or nothing response so the amplitude of the action potential cannot be smaller.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 27
Incorrect
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Your consultant requests that you do a lumbar puncture on a patient who is suspected of having meningitis. This patient, a 15-year-old female, presented to the emergency department with a fever, headache, and neck stiffness. Where should you aspirate a sample of CSF?
Your Answer:
Correct Answer: Subarachnoid space
Explanation:A lumbar puncture, also known as a spinal tap, is a procedure that involves inserting a needle into the lower back’s lumbar region.
A needle is inserted into the space between the arachnoid mater and the pia mater, also known as the subarachnoid space, to remove a sample of cerebrospinal fluid.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 28
Incorrect
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Detection of urinary Bence-Jones protein would be most suggestive of which of the following malignancies:
Your Answer:
Correct Answer: Multiple myeloma
Explanation:Bence Jones proteins are monoclonal immunoglobulin light chains found in urine (and plasma) of some patients with myeloma. Because of their relatively small size, light chains are readily excreted into the urine. The presence of significant amounts of Bence Jones proteins in urine is indicative of malignant B cell proliferation.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 29
Incorrect
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A 30-year-old male with a known allergy to natural latex rubber presents with an allergic reaction to a food he has just eaten.
Which ONE of these foods is most likely to cause an associated hypersensitivity in him?Your Answer:
Correct Answer: Banana
Explanation:About one third of patients with allergy to natural latex rubber (NRL) have an associated allergy to some plant-derived foods. It is known as the latex-fruit syndrome and occurs commonly with consumption of fresh fruits. Banana and avocado are the most implicated fruits but it can also be seen with tomato, kiwi and chestnut.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 30
Incorrect
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Which of the following is the most abundant peripheral blood leucocyte:
Your Answer:
Correct Answer: Neutrophils
Explanation:Neutrophils are the most abundant peripheral blood leucocyte, comprising about 50 – 70% of circulating white cells. Neutrophils have a characteristic dense nucleus consisting of between two and five lobes, and a pale cytoplasm with an irregular outline containing many fine pink-blue or grey-blue granules. The granules are divided into primary, which appear at the promyelocyte stage, and secondary, which appear at the myelocyte stage and predominate in the mature nucleus. Both types of granule are lysosomal in origin; the primary contains myeloperoxidase and other acid hydrolases; the secondary contains lactoferrin, lysozyme and other enzymes. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 31
Incorrect
-
A 53 year old women presents to the emergency room with a chronic cough. The pulmonary receptors likely to be involved in causing her cough are:
Your Answer:
Correct Answer: Irritant receptors
Explanation:Throughout the airways, there are irritant receptors which are located between epithelial cells which are made of rapidly adapting afferent myelinated fibres in the vagus nerve. A cough is as a result of receptor stimulation located in the trachea, hyperpnoea is as a result of receptor stimulation in the lower airway. Stimulation may also result in reflex bronchial and laryngeal constriction. Many factors can stimulate irritant receptors. These include irritant gases, smoke and dust, airway deformation, pulmonary congestion, rapid inflation/deflation and inflammation. Deep augmented breaths or sighs seen every 5 – 20 minutes at rest are due to stimulation of these irritant receptors. This reverses the slow lung collapse that occurs in quiet breathing.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 32
Incorrect
-
During quiet respiration, position of the right oblique fissure can be marked by a line drawn on the thoracic wall that:
Your Answer:
Correct Answer: Begins at the spinous process of T4, crosses the fifth intercostal space laterally and follows the contour of rib 6 anteriorly.
Explanation:During quiet respiration, the approximate position of the right oblique fissure can be marked by a line on the thoracic wall that begins at the spinous process of vertebra T4, crosses the fifth intercostal space laterally and then follows the contour of rib 6 anteriorly.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 33
Incorrect
-
A patient presents complaining of visual loss. On examination you note a contralateral homonymous hemianopia. Where is the most likely site of the lesion:
Your Answer:
Correct Answer: Optic tract
Explanation:At the optic chiasm, fibres from the medial (nasal) half of each retina crossover, forming the right and left optic tracts.
The left optic tract contains fibres from the left lateral (temporal) retina and the right medial retina.
The right optic tract contains fibres from the right lateral retina and the left medial retina.
Each optic tract travels to its corresponding cerebral hemisphere to reach its lateral geniculate nucleus (LGN) located in the thalamus where the fibres synapse.
A lesion of the optic tract will cause a contralateral homonymous hemianopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 34
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 35
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 36
Incorrect
-
A six-year-old boy presents with coryzal symptoms that have persisted for more than two weeks. He was born and raised in the Middle East. His mother claims he has been tired and has complained of various 'aches and pains.' On examination, you find splenomegaly and enlarged cervical lymph nodes. His legs and arms are covered in petechiae.
In this case, what is the most likely diagnosis?Your Answer:
Correct Answer: Acute lymphoblastic leukaemia (ALL)
Explanation:ALL is the most common leukaemia in children, with a peak incidence between the ages of 2 and 5.
ALL has a wide range of clinical symptoms, but many children present with an acute illness that resembles coryza or a viral infection. ALL also has the following features:
Weakness and sluggishness all over
Muscle, joint, and bone pain that isn’t specific
Anaemia
Petechiae and unexplained bruising
Oedema
Lymphadenopathy
HepatosplenomegalyThe following are typical features of a full blood count in patients with ALL:
Anaemia (normocytic or macrocytic)
Leukopenia affects about half of the patients (WCC 4 x 109/l).
Around 25% of patients have leucocytosis (WCC > 10 x 109/l).
Around 25% of patients have hyperleukocytosis (WCC > 50 x 109/l).
Thrombocytopaenia -
This question is part of the following fields:
- Haematology
- Pathology
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Question 37
Incorrect
-
Which of the following describes the site of a Meckel's diverticulum:
Your Answer:
Correct Answer: Ileum
Explanation:Meckel’s lies on the antimesenteric surface of the middle-to-distal ileum, approximately 2 feet proximal to the ileocaecal junction. It appears as a blind-ended tubular outpouching of bowel, about 2 inches long, occurring in about 2% of the population, and may contain two types of ectopic tissue (gastric and pancreatic). The rich blood supply to the diverticulum is provided by the superior mesenteric artery.Proximal to the major duodenal papilla the duodenum is supplied by the gastroduodenal artery (branch of the coeliac trunk) and distal to the major duodenal papilla it is supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery). The arterial supply to the jejunoileum is from the superior mesenteric artery.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 38
Incorrect
-
An 80-year-old patient with a history of chronic heart failure presents to you. Examination reveals widespread oedema.
Which statement about plasma oncotic pressure (π p ) is true?Your Answer:
Correct Answer: The influence of π p on fluid movement is negligible if the capillary reflection co-efficient is 0.1
Explanation:Plasma oncotic pressure (πp) is typically 25-30 mmHg.
70% of π p is generated by albumin so Hypoalbuminemia will decrease π p
The osmotic power of albumin is enhanced by the Gibbs-Donnan effect.
The influence of π p on fluid movement is negligible if the capillary reflection coefficient is 0.1. Another way of saying a vessel is highly permeable is saying the reflection coefficient is close to 0.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 39
Incorrect
-
A 45-year-old businessman returns from a trip to West Africa with headaches and intermittent fevers. Thick and thin films are sent to the lab and a diagnosis is made of malaria. The patient is started on treatment but his condition deteriorates and he develops jaundice, renal failure and haemoglobinuria.
Which of the following is the MOST likely causative organism? Select ONE answer only.Your Answer:
Correct Answer: Plasmodium falciparum
Explanation:Malaria is an infectious disease transmitted by female of theAnophelesgenus of mosquito. It is a parasitic infection caused by the genusPlasmodium. Five species are recognized as causing disease in humans;Plasmodium falciparum,Plasmodium ovale,Plasmodium vivax,Plasmodium malariaeandPlasmodium knowlesi.
The classic symptom of malaria is the malarial paroxysm, a cyclical occurrence of a cold phase, where the patient experiences intense chills, a hot stage, where the patient feels extremely hot and finally a sweating stage, where the fever declines and the patient sweats profusely. On examination the patient may show signs of anaemia, jaundice and have hepatosplenomegaly without evidence of lymphadenopathy.Plasmodium falciparum is the most serious form and is responsible for most deaths. Severe or complicated malaria is suggested by the presence of impaired consciousness, seizures, hypoglycaemia, anaemia, renal impairment, respiratory distress and spontaneous bleeding.
Plasmodium falciparum is the most likely type in this case in view of the presentation.
Haemoglobinuria and renal failure following treatment is suggestive of blackwater fever, which is caused byPlasmodium falciparum. An autoimmune reaction between the parasite and quinine causes haemolysis, haemoglobinuria, jaundice and renal failure. This can be fatal.
The benign malarias: P.vivax, P. malariae and P.ovale are usually treated with chloroquine. A course of primaquine is also required in P.vivax and P.ovale infection. Artesunate is the drug treatment of choice for Plasmodium falciparum malaria. Quinine can still be used where artesunate is not available. Often combination therapy with drugs such as doxycycline or fansidar is also required. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 40
Incorrect
-
Regarding Cryptococcus neoformans, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Patients with complement deficiency are at particular risk of infection.
Explanation:Cryptococcus neoformans typically causes infection in patients with lymphoma, those taking steroid or cytotoxic therapy, those with T-cell deficiency e.g. AIDS and those with intense exposure, such as pigeon fanciers.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 41
Incorrect
-
Which of the following best describes the popliteal artery's course?
Your Answer:
Correct Answer: After exiting the popliteal fossa terminates at the lower border of the popliteus muscle
Explanation:The popliteal artery divides into the anterior and posterior tibial arteries at the lower border of the popliteus after exiting the popliteal fossa between the gastrocnemius and popliteus muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 42
Incorrect
-
A 29 year old woman is unable to invert her foot after sustaining an injury to her leg playing water-polo. Which of the following nerves are most likely damaged:
Your Answer:
Correct Answer: Tibial and deep fibular nerve
Explanation:Inversion of the foot is primarily produced by the tibialis anterior and the tibialis posterior muscles, innervated by the deep fibular nerve and the tibial nerve respectively.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 43
Incorrect
-
All of the following statements regarding Helicobacter pylori is considered true, except:
Your Answer:
Correct Answer: Serum antibody levels should be used to check for successful eradication
Explanation:Helicobacter pylori is a curved, non-spore forming, Gram-negative bacteria that is primarily linked to gastric infections. Once acquired, it colonizes the stomach for a long time and can cause a low-grade inflammatory process, producing a chronic superficial gastritis.
H. pylori can be recovered from gastric biopsy materials. Samples must be transported quickly to the laboratory.
Helicobacter infections usually are identified by nonculture methods. H. pylori can be presumptively identified in a gastric biopsy specimen by testing for the presence of a rapid urease reaction.Serologic testing is an important screening method for the diagnosis of H. pylori infection. It can also be diagnosed by faecal antigen detection, microscopic examination of stained gastric tissue, and DNA amplification tests.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 44
Incorrect
-
Insulin is produced by which of the following pancreatic cells:
Your Answer:
Correct Answer: β cells
Explanation:Insulin is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas. Insulin is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds. Proinsulin is synthesised as a single-chain peptide. Within storage granules, a connecting peptide (C peptide) is removed by proteases to yield insulin. Insulin release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin, but most output is driven by the rise in plasma glucose concentration that occurs after a meal. The effects of insulin are mediated by the receptor tyrosine kinase.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 45
Incorrect
-
Which of the following is NOT an adverse effect associated with warfarin therapy:
Your Answer:
Correct Answer: Neutropenia
Explanation:Adverse effects of warfarin:
The most common adverse effect of warfarin is bleedingOther common adverse effects of warfarin include nausea, vomiting, diarrhoea, jaundice, hepatic dysfunction, pancreatitis, pyrexia, alopecia, purpura, and rash
Skin necrosis is a rare but serious adverse effect of warfarin; treatment with warfarin should be stopped if warfarin related skin necrosis is suspected
Calciphylaxis is a rare, but a very serious condition that causes vascular calcification and cutaneous necrosis
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 46
Incorrect
-
A pheochromocytoma is diagnosed in a 38-year-old female who has had episodes of acute sweating, palpitations, and paroxysmal hypertension.
Which of the following is the MOST SUITABLE INITIAL TREATMENT?Your Answer:
Correct Answer: Alpha-blocker
Explanation:A phaeochromocytoma is a rare functional tumour that develops in the adrenal medulla from chromaffin cells. Extra-adrenal paragangliomas (extra-adrenal pheochromocytomas) are tumours that arise in the sympathetic nervous system’s ganglia and are closely connected to extra-adrenal paragangliomas (extra-adrenal pheochromocytomas). Catecholamines are secreted by these tumours, which generate a variety of symptoms and indications associated with sympathetic nervous system hyperactivity.
Hypertension is the most prevalent presenting symptom, which can be continuous or intermittent.Symptoms are usually intermittent, occurring anywhere from many times a day to occasionally. The symptoms of the condition tend to grow more severe and frequent as the disease progresses.
The ultimate therapy of choice is surgical resection, and if full resection is done without metastases, hypertension is typically cured.Preoperative medical treatment is critical because it lowers the risk of hypertensive crises during surgery. This is commonly accomplished by combining non-competitive alpha-blockers (such as phenoxybenzamine) with beta-blockers. To allow for blood volume expansion, alpha-blockade should be started at least 7-10 days before surgery. Beta-blockade, which helps to regulate tachycardia and some arrhythmias, can be started after this is accomplished. Hypertensive crises can be triggered if beta-blockade is started too soon.
There should also be genetic counselling, as well as a search for and management of any linked illnesses. -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 47
Incorrect
-
Which of the following is a primary action of calcitonin:
Your Answer:
Correct Answer: Decreased bone resorption through inhibition of osteoclast activity
Explanation:Calcitonin is a 32 amino acid polypeptide that is primarily synthesised and released by the parafollicular cells (C-cells) of the thyroid gland in response to rising or high levels of plasma Ca2+ions. Its primary role is to reduce the plasma calcium concentration, therefore opposing the effects of parathyroid hormone.
Secretion of calcitonin is stimulated by:
– Increased plasma calcium concentration
– Gastrin
– Pentagastrin
– The main actions of calcitonin are:
– Inhibition of osteoclastic activity (decreasing calcium and phosphate resorption from bone)
– Stimulation of osteoblastic activity
– Decreases renal calcium reabsorption
– Decreases renal phosphate reabsorption -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 48
Incorrect
-
A 50-year-old woman with painful joints had some blood tests done with her GP. The test showed she had anti-double stranded DNA antibodies.
Which one of these disorders is most likely to be associated with anti-double stranded DNA antibodies?Your Answer:
Correct Answer: Systemic lupus erythematosus (SLE)
Explanation:CREST syndrome is usually associated with anti-centromere antibodies.
Primary biliary cirrhosis is associated with anti-mitochondrial antibodies.
Sjogren’s syndrome is associated with anti-Ro and anti-La antibodies.
Polymyositis is associated with anti-Jo1 antibodies.
Anti-double stranded DNA antibodies are highly characteristic of systemic lupus erythematosus (SLE). They are a group of anti-nuclear antibodies (ANA) that target double stranded DNA and are implicated in the pathogenesis of lupus nephritis.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 49
Incorrect
-
The following statements about cross-sectional studies are true EXCEPT?
Your Answer:
Correct Answer: They can be used to determine the relative risk of a condition
Explanation:The UK national census is an example of a cross-sectional study.
Cross-sectional studies can be used to assess the prevalence of a condition, and support or refute inferences of cause and effect.
Cross-sectional studies are observations of the frequency and characteristics of a disease in a given population at one particular point in time.
Cross-sectional studies do not differentiate between cause and effect and also do not establish the sequence of events.
Cross-sectional studies cannot be used to calculate the relative risk of a condition.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 50
Incorrect
-
One of these statements about significance tests is true.
Your Answer:
Correct Answer: A p value of less than 1 in 20 is considered ‘statistically significant’
Explanation:The p value is statistically significant when it is less than 0.05 (5% or 1 in 20).
Statistical significance is not the same as clinical significance.
The null hypothesis states that there is no difference between the groups.
The power of a study is the probability of correctly rejecting the null hypothesis when it is false.
A type I error occurs when the null hypothesis has been rejected when it is true. A type II error occurs when the null hypothesis has been accepted when it is actually false.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 51
Incorrect
-
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 52
Incorrect
-
A patient presents to ED complaining of a purulent discharge, urethral discomfort and dysuria. You suspect gonorrhoea. Which of the following cell components produced by Neisseria gonorrhoeae is responsible for attachment to host cells:
Your Answer:
Correct Answer: Pili
Explanation:Infection of the genital mucosa by Neisseria gonorrhoeae involves attachment to and invasion of epithelial cells. Initial adherence of gonococci to columnar epithelial cells is mediated by type IV pili assembled from pilin subunit PilE proteins and pilus tip-associated PilC proteins, it then invades the epithelial layer, triggering a local acute inflammatory response.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 53
Incorrect
-
Which of the following is NOT an indication for a H1 receptor antihistamine:
Your Answer:
Correct Answer: Gastroesophageal reflux disease
Explanation:Antihistamines are competitive inhibitors at the H1-receptor (in contrast to H2 receptor antagonists used to decrease gastric acid secretion in gastroesophageal reflux disease).
Indications:
Allergic rhinitis and conjunctivitis
Urticarial rashes, pruritus, insect bites and stings
Angioedema
Anaphylaxis (second line adjunct to adrenaline)
Nausea/vomiting and prevention of motion sickness
Insomnia -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 54
Incorrect
-
A 60-year-old man presents with marked breathlessness. He has with a history of ischaemic heart disease. On examination, there is coarse bibasal crackles, marked peripheral oedema and chest X-ray taken is consistent with severe pulmonary oedema. RR is 28 per minute.
Which receptor is responsible for detecting pulmonary oedema and the subsequent increase in respiratory rate?Your Answer:
Correct Answer: Juxtacapillary receptors
Explanation:Pulmonary oedema causes stimulation of the Juxtacapillary receptors (J receptors) leading to a reflex increase in breathing rate. These receptors are also thought to be involved in the sensation of dyspnoea. The J receptors are sensory cells and are located within the alveolar walls in juxtaposition to the pulmonary capillaries.
Aortic baroreceptor are involved in detecting blood pressure
Central chemoreceptors detect changes in CO2 and hydrogen ion within the brain
Atrial volume receptors regulate plasma volume
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 55
Incorrect
-
A 29-year-old volunteer returns from a recent trip to the middle east with profuse watery diarrhoea. You make a diagnosis of cholera and organize a hospital admission for rehydration with intravenous fluids.
What is the mechanism of action of cholera toxin?
Your Answer:
Correct Answer: ADP-ribosylation of the G regulatory protein
Explanation:Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.
The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl.
The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.
Incubation period is between 2 and 5 days, but can be as short as just a few hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 56
Incorrect
-
An ambulance transports a 40-year-old man to the hospital. He ingested a significant amount of aspirin.
In the early stages of an aspirin overdose, which form of acid-base problem should you anticipate?Your Answer:
Correct Answer: Respiratory alkalosis
Explanation:When you take too much aspirin, you have a mix of respiratory alkalosis and metabolic acidosis. Respiratory centre stimulation produces hyperventilation and respiratory alkalosis in the early phases. The direct acid actions of aspirin tend to create a higher anion gap metabolic acidosis in the latter phases.
Below summarizes some of the most common reasons of acid-base abnormalities:Respiratory alkalosis:
– Hyperventilation (e.g. anxiety, pain, fever)
– Pulmonary embolism
– Pneumothorax
– CNS disorders (e.g. CVA, SAH, encephalitis)
– High altitude
– Pregnancy
– Early stages of aspirin overdoseRespiratory acidosis:
– COPD
– Life-threatening asthma
– Pulmonary oedema
– Respiratory depression (e.g. opiates, benzodiazepines)
– Neuromuscular disease (e.g. Guillain-Barré syndrome, muscular dystrophy
– Incorrect ventilator settings (hypoventilation)
– ObesityMetabolic alkalosis:
– Vomiting
– Cardiac arrest
– Multi-organ failure
– Cystic fibrosis
– Potassium depletion (e.g. diuretic usage)
– Cushing’s syndrome
– Conn’s syndromeMetabolic acidosis (with raised anion gap):
– Lactic acidosis (e.g. hypoxaemia, shock, sepsis, infarction)
– Ketoacidosis (e.g. diabetes, starvation, alcohol excess)
– Renal failure
– Poisoning (e.g. late stages of aspirin overdose, methanol, ethylene glycol)Metabolic acidosis (with normal anion gap):
– Renal tubular acidosis
– Diarrhoea
– Ammonium chloride ingestion
– Adrenal insufficiency -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 57
Incorrect
-
Discontinuous capillaries are typically found where in the body:
Your Answer:
Correct Answer: Reticuloendothelial system
Explanation:Discontinuous capillaries, found in the reticuloendothelial system (bone marrow, liver and spleen), have large gaps between endothelial cells and are permeable to red blood cells.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 58
Incorrect
-
What is the direct mechanism of action of digoxin as a positive inotrope:
Your Answer:
Correct Answer: Inhibition of Na+/K+ ATPase pump
Explanation:Digoxin directly inhibits membrane Na+/K+ ATPase, which is responsible for Na+/K+ exchange across the myocyte cell membrane. This increases intracellular Na+ and produces a secondary increase in intracellular Ca2+ that increases the force of myocardial contraction. The increase in intracellular Ca2+ occurs because the decreased Na+ gradient across the membrane reduces the extrusion of Ca2+ by the Na+/Ca2+ exchanger that normally occurs during diastole. Digoxin and K+ ions compete for the receptor on the outside of the muscle cell membrane, and so the effects of digoxin may be dangerously increased in hypokalaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 59
Incorrect
-
A 45-year-old man had a painless superficial inguinal lymphadenopathy. It was later found to be malignant. Which of the following parts of the body is most likely the origin of this cancerous lymph node?
Your Answer:
Correct Answer: Anal canal
Explanation:A cancer of the anal canal below the pectinate line would spread to the superficial inguinal lymph nodes.
Anal cancer often spreads through lymphatic drainage to the internal iliac lymph nodes in lesions above the pectinate line and to the superficial inguinal lymph nodes in lesions below the pectinate line.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 60
Incorrect
-
Which of the following is the most abundant immunoglobulin in plasma:
Your Answer:
Correct Answer: IgG
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).
IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.
IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 61
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 62
Incorrect
-
A patient had a left Colles' fracture, which you were able to repair. It was their second fragility fracture this year, and you'd like to provide them some tips on how to keep their bones healthy.
What percentage of the calcium in the body is kept in the bones? Only ONE response is acceptable.Your Answer:
Correct Answer: 99%
Explanation:Calcium is stored in bones for nearly all of the body’s calcium, but it is also found in some cells (most notably muscle cells) and the blood. The average adult diet comprises roughly 25 mmol of calcium per day, of which the body absorbs only about 5 mmol.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 63
Incorrect
-
Diagnosis of HIV is predominantly made through which of the following:
Your Answer:
Correct Answer: Antibody detection
Explanation:Diagnosis of HIV is predominantly made through detection of HIV antibody and p24 antigen. Viral load (viral PCR) and CD4 count are used to monitor progression of disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 64
Incorrect
-
A patient suffers from an injury and as a consequence, is unable to externally rotate his femur when his hip is extended. You suspect a nerve injury to the obturator internus muscle. Which of the following nerves innervate the obturator internus muscle?
Your Answer:
Correct Answer: Obturator internus nerve
Explanation:The obturator internus is innervated by the obturator internus nerve (L5–S2), a branch of sacral plexus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 65
Incorrect
-
The following are all examples of type III hypersensitivity EXCEPT for:
Your Answer:
Correct Answer: Goodpasture's syndrome
Explanation:Examples of type III reactions include:
Extrinsic allergic alveolitis
Systemic lupus erythematosus (SLE)
Post-streptococcal glomerulonephritis
Reactive arthritis
Rheumatoid arthritis -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 66
Incorrect
-
After a work-related accident, a 33-year old male is taken to the emergency room with difficulty in adduction and flexion of his left arm at the glenohumeral joint. The attending physician is suspects involvement of the coracobrachialis muscle.
The nerve injured in the case above is?Your Answer:
Correct Answer: The musculocutaneous nerve
Explanation:The coracobrachialis muscle is innervated by the musculocutaneous nerve (C5-C7) a branch of the lateral cord of the brachial plexus.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 67
Incorrect
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A 62-year-old man complains of chest pain and goes to the emergency room. You diagnose him with an acute coronary syndrome and prescribe enoxaparin as part of his treatment plan.
Enoxaparin inactivates which of the following?Your Answer:
Correct Answer: Thrombin
Explanation:Enoxaparin is a low molecular weight heparin (LMWH) that works in the same way as heparin by binding to and activating the enzyme inhibitor antithrombin III. Antithrombin III inactivates thrombin by forming a 1:1 complex with it. Factor Xa and a few other clotting proteases are also inhibited by the heparin-antithrombin III complex.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 68
Incorrect
-
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 69
Incorrect
-
A 69-year-old woman with new-onset back pain was diagnosed with osteopenia, osteolytic lesions, and vertebral collapse after undergoing a radiographic examination. Her laboratory results revealed anaemia and hypercalcemia. These findings most likely indicate what condition?
Your Answer:
Correct Answer: Myeloma
Explanation:Bone pain, pathologic fractures, weakness, anaemia, infection, hypercalcemia, spinal cord compression, and renal failure are all signs and symptoms of multiple myeloma (MM). The patient’s condition matched the signs and symptoms of myeloma.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 70
Incorrect
-
C3 deficiency leads to particular susceptibility of infection with which of the following:
Your Answer:
Correct Answer: Encapsulated bacteria
Explanation:Macrophages and neutrophils have C3b receptors and they phagocytose C3b-coated cells. C3 deficiency thus leads to increased susceptibility of infection with encapsulated organisms (e.g. S. pneumoniae, H. influenzae).The early stages of the complement cascade leading to coating of the cells with C3b can occur by two different pathways:The classical pathway usually activated by IgG or IgM coating of cellsThe alternative pathway which is more rapid and activated by IgA, endotoxin and other factors
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 71
Incorrect
-
Which of the following occurs at the transverse thoracic plane:
Your Answer:
Correct Answer: Bifurcation of the trachea
Explanation:A way to help remember the structures transected by the transverse thoracic plane is CLAPTRAP:
C: cardiac plexus
L: ligamentum arteriosum
A: aortic arch (inner concavity)
P: pulmonary trunk
T: tracheal bifurcation (carina)
R: right-to-left movement of the thoracic duct (posterior to the oesophagus)
A: azygos vein drains into superior vena cava
P: pre-vertebral fascia and pre-tracheal fascia end -
This question is part of the following fields:
- Anatomy
- Thorax
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Question 72
Incorrect
-
A 41-year-old female patient presents with jaundice. She tells you that she is known to have a chronic hepatitis B infection.
Which of the following hepatitis B serology results is consistent with a patient that is chronically infected? Select ONE answer only.Your Answer:
Correct Answer: HBsAg positive, anti-HBc positive, IgM anti-HBc negative
Explanation:Hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, that is the first serologic marker to appear in a new acute infection.It can be detected as early as 1 week and as late as 9 weeks. It can be detected in high levels in serum during acute or chronic hepatitis B virus infection. The presence of HBsAg indicates that the person is infectious. The body normally produces antibodies to HBsAg as part of the normal immune response to infection. HBsAg is the antigen used to make hepatitis B vaccine.
Hepatitis B surface antibody (anti-HBs) indicates recovery and immunity from the hepatitis B virus infection. Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B.
Total hepatitis B core antibody (anti-HBc): Appears at the onset of symptoms in acute hepatitis B and persists for life. The presence of anti-HBc indicates previous or ongoing infection with hepatitis B virus in an undefined time frame. It is not present following hepatitis B vaccination.
IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates recent infection with hepatitis B virus (<6 months). Its presence indicates acute infection.
The following table summarises the presence of hepatitis B markers according to each situation:
Susceptible to infection:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = NegativeImmune due to natural infection:
HBsAg = Negative
Anti-HBc = Positive
Anti-HBs = PositiveImmune due to vaccination:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = PositiveAcute infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = PositiveChronic infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Negative -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 73
Incorrect
-
Regarding non-Hodgkin lymphoma (NHL), which of the following statements is CORRECT:
Your Answer:
Correct Answer: There is a much greater predilection to disseminate to extranodal sites than in Hodgkin lymphoma.
Explanation:Non-Hodgkin’s lymphoma (NHL) refers to a group of lymphoproliferative malignancies (about 85% of B-cell and 15% of T or NK (natural killer) cell origin) with different behavioural patterns and treatment responses. This group of malignancies encompasses all types of lymphoma without Reed-Sternberg cells being present. The Reed-Sternberg cell is classically seen in Hodgkin’s lymphoma.
NHL is five times as common as Hodgkin’s lymphoma. The peak incidence of NHL is in the 50-70 years age group, it affects men and women equally, but affects the Caucasian population more commonly than black and Asian ethnic groups.
The following are recognised risk factors for NHL:
Chromosomal translocations and molecular rearrangements
Epstein-Barr virus infection
Human T-cell leukaemia virus type-1 (HTLV-1)
Hepatitis C
Congenital and acquired immunodeficiency states
Autoimmune disorders, e.g. Sjogren’s syndrome and Hashimoto’s thyroiditis
The most common clinical features at presentation are:
Lymphadenopathy (typically asymmetrical and painless)
Weight loss
Fatigue
Night sweats
Hepatosplenomegaly
For clinical purposes, NHL is divided into three groups: indolent, high-grade, and lymphoblastic.
Indolent (low-grade) NHL:
The cells are relatively mature
Disease follows an indolent course without treatment
Often acceptable to follow a ‘watch and wait’ strategy
Local radiotherapy often effective
Relatively good prognosis with median survival of 10 years
High-grade NHL:
Cells are immature
Disease progresses rapidly without treatment
Significant number of patients can be cured with intensive combination chemotherapy regimens
Approximately 40% cure rate
Lymphoblastic NHL:
Cells are very immature and have a propensity to involve the CNS
Treatment and progression are similar to that of acute lymphoblastic leukaemia (ALL) -
This question is part of the following fields:
- Haematology
- Pathology
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Question 74
Incorrect
-
The only statement that is correct regarding diffusion is which of the following?
Your Answer:
Correct Answer: The permeability of a membrane is related to the membrane thickness and composition.
Explanation:Passive diffusion is a process that describes the movement down a concentration gradient. This process accounts for movement across small distances like within the cytosol or across membranes. Factors that affect the diffusion of a substance across a membrane are the permeability (p) of the membrane, a difference in concentration across the membrane and the membrane area over which diffusion occurs. The membrane thickness and composition, and the diffusion coefficient of the substance also affects the permeability. Fick’s law describes the rate of diffusion of a substance within a solution, which can be modified to describe the rate of diffusion across a membrane.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 75
Incorrect
-
All of the statements regarding vascular tone are correct except:
Your Answer:
Correct Answer: Most endogenous vasodilators act by decreasing levels of cAMP or cGMP.
Explanation:Most vasoconstrictors bind to G-protein coupled receptors. These mediate elevation in intracellular [Ca2+] which leads to vascular smooth muscle contraction. Important vasoconstrictors include noradrenaline, endothelin-1 and angiotensin II.
Increased intracellular Ca2+ is as a result of the release of Ca2+from the sarcoplasmic reticulum and depolarisation and entry of Ca2+via L-type voltage-gated Ca2+channels. Most types of vascular smooth muscle do not generate action potentials – instead, the depolarisation is graded, which allows graded entry of Ca2+.
sequestration by the sarcoplasmic reticulum Ca2+ATPase, removal from the cell by a plasma membrane Ca2+ATPase and Na+/Ca2+exchange decreases intracellular Ca2+, resulting in vasodilation. Relaxation is a result of most endogenous vasodilators when there is an increase in cyclic guanosine monophosphate (cGMP) like nitric oxide) or cyclic adenosine monophosphate (cAMP) like prostacyclin and beta-adrenergic receptor agonists. These activate protein kinases causing substrate level phosphorylation.
Clinically effective vasodilators are L-type Ca2+channel blocker drugs. -
This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 76
Incorrect
-
Vitamin D is a group of secosteroids that play a role in calcium and phosphate control. Vitamin D's hormonally active metabolite is 1,25-dihydroxycholecalciferol.
Which enzyme hydroxylates 25-hydroxycholecalciferol to form 1,25-dihydroxycholecalciferol?Your Answer:
Correct Answer: 1-alpha-hydroxylase
Explanation:The hormone-active metabolite of vitamin D is 1,25-dihydroxycholecalciferol (commonly known as calcitriol). Its activities raise calcium and phosphate levels in the bloodstream.
In the presence of UVB light, 7-dehydrocholesterol is converted to cholecalciferol in the epidermal layer of the skin, resulting in 1,25-dihydroxycholecalciferol.
Cholecalciferol is then converted to 25-hydroxycholecalciferol in the endoplasmic reticulum of liver hepatocytes by 25-hydroxylase (calcifediol).
Finally, 1-alpha-hydroxylase converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol in the kidney. The key regulatory point in the formation of 1,25-dihydroxycholecalciferol is 1-alpha-hydroxylase, which is induced by parathyroid hormone or hypophosphatemia.
The following are the primary effects of 1,25-dihydroxycholecalciferol:
Calcium and phosphate absorption in the small intestine is increased.
Calcium reabsorption in the kidneys is increased.
Increases phosphate reabsorption in the kidneys.
Increases the action of osteoclastic bacteria (increasing calcium and phosphate resorption from bone)
Inhibits the action of 1-alpha-hydroxylase in the kidneys (negative feedback) -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 77
Incorrect
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You are examining the lower limbs of a 54 year old man who presented after falling from a ladder at home. During your neurological assessment you note a weakness of hip flexion. Which of the following nerves is the most important for flexion of the thigh at the hip joint:
Your Answer:
Correct Answer: Femoral nerve
Explanation:Flexion of the thigh at the hip joint is produced by the sartorius, psoas major, iliacus and pectineus muscles, assisted by the rectus femoris muscle, all innervated by the femoral nerve (except for the psoas major, innervated by the anterior rami of L1 – 3).
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 78
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 79
Incorrect
-
Regarding postural hypotension, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Postural hypotension usually causes a reflex bradycardia.
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 80
Incorrect
-
A 29-year-old woman with a skin infection not responding to first-line antibiotics return for a review clinic appointment. The result of her culture shows growth of methicillin-resistant Staphylococcus aureus (MRSA).
Which among the following antibiotics is methicillin-resistant Staphylococcus aureus usually sensitive to?Your Answer:
Correct Answer: Linezolid
Explanation:Historically, MRSA has been treated successfully with outpatient oral sulphonamides, clindamycin, rifampin, doxycycline, or a combination of these agents. With the development of increasing drug resistance of MRSA to these traditional antimicrobials, there has been a search for more effective antibiotics. One recent study demonstrated that vancomycin, linezolid, and quinupristin-dalfopristin were the most effective antibiotics against multiple strains of MRSA.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 81
Incorrect
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Question 82
Incorrect
-
Regarding ciprofloxacin, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Ciprofloxacin decreases plasma concentrations of theophylline.
Explanation:Ciprofloxacin increases plasma concentrations of theophylline. There is an increased risk of convulsions when quinolones are given with NSAIDs or theophylline. There is an increased risk of tendon damage when quinolones are given with corticosteroids. Quinolones are known to increase the QT-interval and should not be taken with concomitantly with other drugs that are known to cause QT-interval prolongation. There is an increased risk of myopathy when erythromycin or clarithromycin are taken with simvastatin or atorvastatin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 83
Incorrect
-
You're called to a cardiac arrest in your Emergency Department resuscitation area. The rhythm strip is shown in the diagram below. Defibrillation has already been attempted three times on the patient. You intended to administer amiodarone, but your department has informed you that it is not available. In these circumstances, if amiodarone is not available, which of the following drugs is recommended by the ALS guidelines?
Your Answer:
Correct Answer: Lidocaine
Explanation:If amiodarone is unavailable in VF/pVT arrests, lidocaine at a dose of 1 mg/kg can be used instead, according to the latest ALS guidelines. If amiodarone has already been given, no lidocaine should be given.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 84
Incorrect
-
Which of the following is NOT one of the cardinal features of acute inflammation:
Your Answer:
Correct Answer: Discharge
Explanation:Classic signs:
Rubor (redness)
Calor (heat)
Dolour (pain)
Tumour (swelling)
Functio laesa (loss of function)
These classic signs are produced by a rapid vascular response and cellular events. The main function of these events is to bring elements of the immune system to the site of injury and prevent further tissue damage. -
This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 85
Incorrect
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Which of the following is NOT a typical feature of a lesion to the vestibulocochlear nerve:
Your Answer:
Correct Answer: Hyperacusis
Explanation:Hyperacusis is increased acuity of hearing with hypersensitivity to low tones resulting from paralysis of the stapedius muscle, innervated by the facial nerve. General sensation to the face and to the anterior two-thirds of the tongue is carried by the divisions of the trigeminal nerve (although taste to the anterior two-thirds of the tongue is supplied by the facial nerve). Eye movements are mediated by the oculomotor, trochlear and abducens nerve. Ptosis results from paralysis of the levator palpebrae superioris, innervated by the oculomotor nerve, or the superior tarsal muscle, innervated by the sympathetic chain.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 86
Incorrect
-
A 20-year-old female presents with painful wrist following a fall while skating. X-rays shows fracture of the ulna.
The initial phase of bone healing is?
Your Answer:
Correct Answer: Haematoma at the fracture site
Explanation:Haemorrhage occurs into the fracture site from the ruptured vessels in the bone marrow and those supplying the periosteum immediately after fracture. This hematoma formation is the first phase of bone healing.
The 4 stages of bone healing are:
Haematoma at the fracture site (provides a framework for healing)
Callus formation
Lamellar bone formation
Remodelling -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 87
Incorrect
-
Which of the following anatomical structures is most likely the cause of oedema and erythema of the arm in a patient who underwent modified radical mastectomy and radiotherapy?
Your Answer:
Correct Answer: Axillary lymph nodes
Explanation:Arm oedema is one of the sequelae after breast cancer surgery and radiation therapy. Arm oedema in the breast cancer patient is caused by interruption of the axillary lymphatic system by surgery or radiation therapy, which results in the accumulation of fluid in subcutaneous tissue in the arm, with decreased distensibility of tissue around the joints and increased weight of the extremity. Chronic inflammatory changes result in both subcutaneous and lymph vessel fibrosis.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 88
Incorrect
-
At which opioid receptors do opioid analgesics act primarily?
Your Answer:
Correct Answer: Mu
Explanation:Opioid receptors are widely distributed throughout the central nervous system. Opioid analgesics mimic endogenous opioid peptides by causing prolonged activation of these receptors, mainly the mu(μ)-receptors which are the most highly concentrated in brain areas involved in nociception.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 89
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 90
Incorrect
-
Which of the following causes increased aldosterone secretion:
Your Answer:
Correct Answer: Decreased blood volume
Explanation:Decreased blood volume stimulates the secretion of renin (because of decreased renal perfusion pressure) and initiates the renin-angiotensin-aldosterone cascade. Angiotensin-converting enzyme (ACE) inhibitors block the cascade by decreasing the production of angiotensin. Hyperosmolarity stimulates antidiuretic hormone (ADH) [not aldosterone] secretion. Hyperkalaemia, not hypokalaemia, directly stimulates aldosterone secretion by the adrenal cortex. ANP inhibits renin secretion, thereby inhibiting the production of angiotensin and aldosterone.
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This question is part of the following fields:
- Physiology
- Renal
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Question 91
Incorrect
-
Which of the following statements about propofol is TRUE:
Your Answer:
Correct Answer: Propofol has some antiemetic action.
Explanation:Propofol has some antiemetic properties. It’s for this reason that it’s used to treat postoperative nausea and vomiting. Propofol is mostly processed in the liver, with the kidneys excreting just around 1% of it unaltered. Propofol, unlike thiopental, does not produce tissue necrosis when it is extravasated. Propofol lowers intracranial pressure via lowering brain metabolic rate and cerebral blood flow. Propofol is thought to be safe for people with bronchial asthma and chronic obstructive pulmonary disease.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 92
Incorrect
-
Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer:
Correct Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).
IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.
IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 93
Incorrect
-
Which of the following statements is correct with regards to Hodgkin's lymphoma?
Your Answer:
Correct Answer: Most patients present with painless asymmetrical lymphadenopathy, with cervical nodes involved most commonly.
Explanation:Lymphoma is a cancer of the lymphatic system, which is part of the body’s germ-fighting network. They are a group of diseases that are caused by malignant lymphocytes. These malignant cells accumulate in lymph nodes and other lymphoid tissue, giving rise to the characteristic clinical feature of lymphadenopathy.
They can be subdivided into Hodgkin lymphoma (HL) which are characterised by the presence of Reed-Sternberg cells, and non-Hodgkin lymphoma (NHL).
Characteristics of HL include:
1. can present at any age but is rare in children and has a peak incidence in young adults,
2. almost 2:1 male predominance.
3. presents with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes.
4. cervical node involvement in 60-70% of cases,
5. axillary node involvement in 10-15%
6. inguinal node involvement in 6-12%.
7. modest splenomegaly during the course of the disease in 50% of patients
8. may occasionally have liver enlargement
9. bone marrow failure involvement is unusual in early disease.
Approximately 85% of patients are cured, but the prognosis depends on age, stage and histology.
Two well‐known but rare symptoms in HL are alcohol‐induced pain and pruritus. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 94
Incorrect
-
A 43 year old lady who has a previous medical history of hyperthyroidism presents to the emergency room with sweating, palpitations and agitation. On examination, she is tachycardic, hypertensive and hyperpyrexic. She recently had a stomach bug and has not been able to take her medication regularly. The best medication to immediately treat her symptoms is which of the following?
Your Answer:
Correct Answer: Propranolol
Explanation:There is a high suspicion of a thyroid crisis in this patient and emergent treatment should be initiated even before the results of TFT’s have returned. Antiadrenergic drugs like IV propranolol should be administered immediately to minimise sympathomimetic symptoms. Antithyroid medications like propylthiouracil or carbimazole should be administered to block further synthesis of thyroid hormones. After thionamide therapy has been started to prevent stimulation of new hormone synthesis, there should then be delayed administration of oral iodine solution. Hydrocortisone administration is also recommended as it treats possible relative adrenal insufficiency while also decreases peripheral conversion of T4 to T3.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 95
Incorrect
-
When a child has chickenpox, how long should he or she be off from school?
Your Answer:
Correct Answer: Until all vesicles have crusted over
Explanation:To avoid the spread of infection, infected patients should be isolated. All lesions should be crusted over before children return to nursery or school, even if the standard exclusion time is 5 days.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 96
Incorrect
-
A 28-year-old woman with history of blunt thoracic trauma develops hypotension chest pain, and breathlessness. A bedside echocardiogram was performed and revealed a large pericardial effusion. Due to this finding, a pericardiocentesis was to be performed.
Which of the following statements is considered true regarding pericardiocentesis?Your Answer:
Correct Answer: The needle should be aimed at the midpoint of the left clavicle
Explanation:Pericardiocentesis is a procedure done to remove fluid build-up in the sac around the heart known as the pericardium. The pericardium can be tapped from almost any reasonable location on the chest wall. However, for the usual blind pericardiocentesis, the subxiphoid approach is preferred. Ideally, 2-D echocardiography is used to guide needle insertion and the subsequent path of the needle/catheter.
In the subxiphoid approach, the needle is inserted 1 cm inferior to the left xiphocostal angle with an angle of 30 degrees from the patient’s chest with a direction towards the left mid-clavicle.
The fingers may sense a distinct give when the needle penetrates the parietal pericardium. Successful removal of fluid confirms the needle’s position.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 97
Incorrect
-
Water is reabsorbed in which portion of the Henle loop:
Your Answer:
Correct Answer: Thin descending limb
Explanation:The loop of Henle consists of three functionally distinct segments: the thin descending segment, the thin ascending segment, and the thick ascending segment. About 20 percent of the filtered water is reabsorbed in the loop of Henle and almost all of this occurs in the thin descending limb. Na+ and Cl-ions are actively reabsorbed from the tubular fluid in the thick ascending limb via the Na+/K+/2Cl-symporter on the apical membrane. Because the thick ascending limb is water-impermeable, ion reabsorption lowers tubular fluid osmolality while raising interstitial fluid osmolality, resulting in an osmotic difference. Water moves passively out of the thin descending limb as the interstitial fluid osmolality rises, concentrating the tubular fluid. This concentrated fluid descends in the opposite direction of fluid returning from the deep medulla still higher osmolality areas.
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This question is part of the following fields:
- Physiology
- Renal
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Question 98
Incorrect
-
The pelvic bone is formed by which of the following:
Your Answer:
Correct Answer: Ilium, ischium and pubis
Explanation:Each pelvic bone is formed by three elements: the ilium (superiorly), the pubis (anteroinferiorly) and the ischium (posteroinferiorly).
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 99
Incorrect
-
A 32-year-old man is dehydrated as he presents with severe vomiting and diarrhoea. He urgently requires resuscitation with intravenous fluid administration. He is also administered metoclopramide.
Which of the following is the true mechanism of action of metoclopramide?Your Answer:
Correct Answer: Dopamine receptor antagonism
Explanation:Metoclopramide is used to treat nausea and vomiting. It works by blocking the central and peripheral D2 (dopamine 2) receptors in the medullary chemoreceptor trigger zone in the vomiting centre (area postrema). It decreases the sensitivity of the visceral sensory nerves that transmit from the GI system to the vomiting centre. Blockade of inhibitory dopamine receptors in the GI tract may allow stimulatory actions of ACh at muscarinic synapses to predominate.
At high doses, metoclopramide also blocks type-2 serotonin receptors though the effect is much weaker.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 100
Incorrect
-
You are instructed by a senior to administer Mannitol to an RTA patient with increased intracranial pressure.
Mannitol is a low molecular weight compound that freely filters at the glomerulus and is not reabsorbed.
Out of the following, which is a contraindication to the use of mannitol?Your Answer:
Correct Answer: Severe pulmonary oedema
Explanation:Mannitol is the most widely used osmotic diuretic that is most commonly used to reduce cerebral oedema and intracranial pressure.
It is recommended to use mannitol for the reduction of CSF pressure/cerebral oedema in a dose of 0.25-2 g/kg as an intravenous infusion over 30-60 minutes. This can be repeated 1-2 times after 4-8 hours if needed.Mannitol has several contraindications and some of them are listed below:
1. Anuria due to renal disease
2. Acute intracranial bleeding (except during craniotomy)
3. Severe cardiac failure
4. Severe dehydration
5. Severe pulmonary oedema or congestion
6. Known hypersensitivity to mannitol -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
