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Question 1
Incorrect
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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: Aspirin
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 2
Correct
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A 4-year-old child has been convulsing for 20 minutes. She has received two doses of lorazepam. She takes phenytoin for maintenance therapy, and you draw up a phenobarbitone infusion.
What dose of phenobarbitone is advised in the treatment of the convulsing child that reaches that stage of the APLS algorithm? Select ONE answer only.Your Answer: 20 mg/kg over 30-60 minutes
Explanation:If a convulsing child reaches step 3 of the APLS algorithm, then a phenytoin infusion should be set up at 20 mg/kg over 20 minutes. If they are already taken phenytoin as maintenance therapy, then a phenobarbitone infusion should be set up at 20 mg/kg over 30-60 minutes.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 3
Correct
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How is measles primarily transmitted:
Your Answer: Respiratory droplet route
Explanation:Measles belongs to the paramyxoviridae group of viruses. The incubation period is 7-18 days (average 10) and it is spread by airborne or droplet transmission. The classical presentation is of a high fever with coryzal symptoms and photophobia with conjunctivitis often being present. The rash that is associated is a widespread erythematous maculopapular rash. Koplik spots are pathognomonic for measles, and are the presence of white lesions on the buccal mucosa.
Differential diagnoses would include:
Rubella
Roseola infantum (exanthem subitom)
Scarlet fever
Kawasaki disease
Erythema infectiosum (5thdisease)
Enterovirus
Infectious mononucleosis
Diagnosis can be confirmed by the following means:
Salivary swab for measles specific IgM
Serum sample for measles specific IgM
Salivary swab for RNA detection
Possible complications include:
Otitis media
Febrile convulsions
Pneumonia
Bronchiectasis
Diarrhoea
Meningitis
Encephalitis
Immunosuppression
Subacute sclerosing panencephalitis
Death -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 4
Incorrect
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A patient presents with an adducted eye at rest which cannot abduct past the midline, which of the following cranial nerves is most likely to be affected:
Your Answer: Trochlear nerve
Correct Answer: Abducens nerve
Explanation:Abducens nerve palsies result in a convergent squint at rest (eye turned inwards) with inability to abduct the eye because of unopposed action of the rectus medialis. The patient complains of horizontal diplopia when looking towards the affected side. With complete paralysis, the eye cannot abduct past the midline.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 5
Incorrect
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Which of the following best describes digoxin:
Your Answer: A negative inotrope and positive chronotrope
Correct Answer: A positive inotrope and negative chronotrope
Explanation:Digoxin is a cardiac glycoside used in the treatment of atrial fibrillation and flutter, and congestive cardiac failure. It acts by inhibiting the membrane Na/K ATPase in cardiac myocytes. This raises intracellular sodium concentration and increases intracellular calcium availability indirectly via Na/Ca exchange. The increase in intracellular calcium levels causes an increases the force of myocardial contraction (positive inotrope), and slows the heart rate (negative chronotrope).
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 6
Correct
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Myocardial contractility is best correlated with the intracellular concentration of:
Your Answer: Ca2+
Explanation:Contractility of myocardial cells depends on the intracellular [Ca2+], which is regulated by Ca2+entry across the cell membrane during the plateau of the action potential and by Ca2+uptake into and release from the sarcoplasmic reticulum (SR).
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 7
Correct
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Mast cells play a significant part in which of the following?
Your Answer: Allergic disease
Explanation:Mast cells play a central role in the response to allergen challenges. The activation of mast cells results in both an early and a delayed phase of inflammation. Mast cells have been implicated in both physiologic and pathogenic processes. Mast cells are important in defence against some bacteria and viruses and contribute to defence against parasites. They are key effector cells in both innate and acquired immunity and are capable of inducing and amplifying both types of responses. Specifically, mast cells are capable of detecting microbial products through surface pattern recognition receptors, and they are involved in the recruitment of other leukocytes, containment of bacterial infections, and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 8
Incorrect
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The fluid in contact with a tube is dragged by frictional forces to the tube's sidewalls. This creates a velocity gradient in which the fluid flow is greatest in the tube's centre.
Which of the following terms most accurately characterizes this flow pattern?Your Answer: Irrotational flow
Correct Answer: Laminar flow
Explanation:The fluid in contact with a tube is dragged by frictional forces at the tube’s sidewalls. This creates a velocity gradient in which the fluid flow is greatest in the tube’s centre.
This is known as laminar flow, and it characterizes the flow in most circulatory and respiratory systems when they are at rest.The velocity of the fluid flow can fluctuate erratically at high velocities, particularly within big arteries and airways, disrupting laminar flow. As a result, resistance increases significantly.
This is known as turbulent flow, and symptoms include heart murmurs and asthmatic wheeze. -
This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 9
Incorrect
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A 40-year-old man has been admitted for alcohol detoxification. You are asked to review the patient's treatment chart and notice that he has been prescribed Pabrinex by one of your colleagues.
Out of the following, which vitamin is not found in Pabrinex?Your Answer: Vitamin B6
Correct Answer: Vitamin B12
Explanation:Pabrinex is indicated in patients that require rapid therapy for severe depletion or malabsorption of water-soluble vitamins B and C, particularly in alcoholism detoxification.
Pabrinex has the following:
1. Thiamine (vitamin B1)
2. Riboflavin (vitamin B2)
3. Nicotinamide (Vitamin B3, niacin and nicotinic acid)
4. Pyridoxine (vitamin B6)
5. Ascorbic acid (vitamin C)
6. GlucoseSuspected or established Wernicke’s encephalopathy is treated by intravenous infusion of Pabrinex/ The dose is 2-3 pairs three times a day for three to five days, followed by one pair once daily for an additional three to five days or for as long as improvement continues.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pharmacology
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Question 10
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 11
Incorrect
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The primary mechanism of action of ketamine is:
Your Answer: N-methyl-D-aspartate (NMDA)-receptor agonist
Correct Answer: N-methyl-D-aspartate (NMDA)-receptor antagonist
Explanation:Ketamine is a non-competitive antagonist of the calcium-ion channel in the NMDA (N-methyl-D-aspartate) receptor. It further inhibits the NMDA-receptor by binding to its phencyclidine binding site. Ketamine also acts at other receptors as an opioid receptor agonist (analgesic effects), as an muscarinic anticholinergic receptor antagonist (antimuscarinic effects) and by blocking fast sodium channels (local anaesthetic effect).
Overdose may lead to panic attacks and aggressive behaviour; rarely seizures, increased ICP, and cardiac arrest
Very similar in chemical makeup to PCP (phencyclidine), but it is shorter acting and less toxic
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 12
Incorrect
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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: Surgery
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 13
Incorrect
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Regarding the cardiac cycle, which of the following statements is INCORRECT:
Your Answer: The length of diastole decreases with increasing heart rate.
Correct Answer: The second heart sound occurs in late diastole caused by closure of the atrioventricular valves.
Explanation:Diastole is usually twice the length of systole at rest, but decreases with increased heart rate. During systole, contraction of the ventricles compresses the coronary arteries and suppresses blood flow. This is particularly evident in the left ventricle, where during systole the ventricular pressure is the same as or greater than that in the arteries and as a result more than 85% of left ventricular perfusion occurs during diastole. This becomes a problem if the heart rate is increased as the diastolic interval is shorter and can result in ischaemia. The second heart sound, caused by closure of the semilunar valves, marks the end of systole.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 14
Incorrect
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A patient who was put on low molecular weight heparin for suspected DVT and was scheduled for an ultrasound after the weekend, arrives at the emergency department with significant hematemesis. Which of the following medications can be used as a heparin reversal agent:
Your Answer:
Correct Answer: Protamine sulfate
Explanation:The management of bleeding in a patient receiving heparin depends upon the location and severity of bleeding, the underlying thromboembolic risk, and the current aPTT (for heparin) or anti-factor Xa activity (for LMW heparin). As an example, a patient with minor skin bleeding in the setting of a mechanical heart valve (high thromboembolic risk) and a therapeutic aPTT may continue heparin therapy, whereas a patient with major intracerebral bleeding in the setting of venous thromboembolism several months prior who is receiving heparin bridging perioperatively may require immediate heparin discontinuation and reversal with protamine sulphate. If haemorrhage occurs it is usually sufficient to withdraw unfractionated or low molecular weight heparin, but if rapid reversal of the effects of the heparin is required, protamine sulphate is a specific antidote (but only partially reverses the effects of low molecular weight heparins). Clinician judgment and early involvement of the appropriate consulting specialists is advised.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 15
Incorrect
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You review an 18-months-old child who seems to be having a reaction following an immunisation she took earlier in the day.
Which statement concerning immunity and vaccination is true?Your Answer:
Correct Answer: The strongest immunological response is seen with natural immunity
Explanation:Vaccination induces ACTIVE adaptive immunity. Actively acquired immunity involves the development of an immune response either due to vaccination or natural exposure to a pathogen and leads to long-lasting resistance to infection.
Immediate protection is achieved with injection of immunoglobulin. The protection is transient lasting only a few weeks and is useful as post-exposure prophylaxis.
Passively acquired immunity usually leads to short-lasting resistance to infection because it does not involve a host immune response.
With inactivated bacteria, a series of primary vaccinations is usually required to induce an adequate immune response. In most cases, boosters are required to sustain adequate immunity.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 16
Incorrect
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Nifedipine commonly causes which of the following adverse effects?
Your Answer:
Correct Answer: Ankle oedema
Explanation:Most common adverse effects of Nifedipine include:
Peripheral oedema (10-30%)
Dizziness (23-27%)
Flushing (23-27%)
Headache (10-23%)
Heartburn (11%)
Nausea (11%) -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 17
Incorrect
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The least likely feature of anaemia is:
Your Answer:
Correct Answer: Narrow pulse pressure
Explanation:Non-specific signs of anaemia include:
1. pallor of mucous membranes or nail beds (if Hb < 90 g/L),
2. tachycardia
3. bounding pulse
4. wide pulse pressure
5. flow murmurs
6. cardiomegaly
7. signs of congestive cardiac failure (in severe cases) -
This question is part of the following fields:
- Haematology
- Pathology
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Question 18
Incorrect
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A 38-year-old woman presented to the emergency room after an incident of slipping and falling onto her back and left hip. Upon physical examination, it was noted that she has pain on hip flexion, but normal hip adduction. Which of the following muscles was most likely injured in this case?
Your Answer:
Correct Answer: Sartorius
Explanation:The hip adductors are a group of five muscles located in the medial compartment of the thigh. These muscles are the adductor longus, adductor brevis, adductor magnus, gracilis, and pectineus.
The hip flexors consist of 5 key muscles that contribute to hip flexion: iliacus, psoas, pectineus, rectus femoris, and sartorius.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 19
Incorrect
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Which of the following clinical features would you least expect to see in a lesion of the frontal lobe:
Your Answer:
Correct Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:Contralateral homonymous hemianopia with macular sparing results from damage to the primary visual cortex of the occipital lobe. Incontinence may occur due to damage of the cortical micturition centre in the prefrontal cortex. Primitive reflexes and inability to problem solve may occur due to damage to the prefrontal cortex. Motor weakness of the contralateral limb with UMN signs may occur due to damage of the primary motor cortex.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 20
Incorrect
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A 25 year old man presents to the emergency room with abdominal pain, vomiting and constipation. A CT scan is done which is suggestive of Meckel's diverticulum. Where does the blood supply of the Meckel's diverticulum originate?
Your Answer:
Correct Answer: Superior mesenteric artery
Explanation:Meckel’s diverticulum has certain classic characteristics.
1. It lies on the antimesenteric border of the middle-to-distal ileum
2. It is approximately 2 feet proximal to the ileocaecal junction
3. It appears as a blind-ended tubular outpouching of bowel
4. It is about 2 inches long,
5. It occurs in about 2% of the population,
6. It may contain two types of ectopic tissue (gastric and pancreatic).
7. The diverticulum is supplied by the superior mesenteric artery.
8. Proximal to the major duodenal papilla the duodenum is supplied by the gastroduodenal artery (branch of the coeliac trunk)
9. Distal to the major duodenal papilla it is supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery).
10. The arterial supply to the jejunoileum is from the superior mesenteric artery. -
This question is part of the following fields:
- Abdomen
- Anatomy
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Question 21
Incorrect
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All of the following statements are considered true regarding nominal variables, except:
Your Answer:
Correct Answer: The central tendency of a nominal variable is given by its median
Explanation:A nominal variable is a type of variable that is used to name, label or categorize particular attributes that are being measured. It takes qualitative values representing different categories, and there is no intrinsic ordering of these categories.
A nominal variable is one of the 2 types of categorical variables and is the simplest among all the measurement variables. Some examples of nominal variables include gender, name, phone, etc.A nominal variable is qualitative, which means numbers are used here only to categorize or identify objects. They can also take quantitative values. However, these quantitative values do not have numeric properties. That is, arithmetic operations cannot be performed on them. If the variable is nominal, the mode is the only measure of central tendency to use.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 22
Incorrect
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Intravenous glucose solutions are typically used in the treatment of all of the following situations except:
Your Answer:
Correct Answer: Hypokalaemia
Explanation:In hypokalaemia, initial potassium replacement therapy should not involve glucose infusions, as glucose may cause a further decrease in the plasma-potassium concentration. Glucose infusions are used for the other indications like diabetic ketoacidosis, hypoglycaemia, routine fluid maintenance in patients who are nil by mouth (very important in children), and in hyperkalaemia.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 23
Incorrect
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Which of the following is NOT a common side effect of adenosine:
Your Answer:
Correct Answer: Yellow vision
Explanation:Common side effects of adenosine include:
Apprehension
Dizziness, flushing, headache, nausea, dyspnoea
Angina (discontinue)
AV block, sinus pause and arrhythmia (discontinue if asystole or severe bradycardia occur) -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 24
Incorrect
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A 34-year-old man presented to the emergency room after being involved in a road traffic accident. Upon observation and examination, it was noted that he was hypotensive and has muffled heart sounds. It was suspected that he has pericardial effusion, so an emergency pericardiocentesis was to be performed.
In performing pericardiocentesis for suspected pericardial effusion, which of the following anatomical sites are at risk of being punctured?Your Answer:
Correct Answer: 1 cm below the left xiphocostal angle
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:
- Abdomen And Pelvis
- Anatomy
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Question 25
Incorrect
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The most common complication of paracetamol overdose is:
Your Answer:
Correct Answer: Hepatic failure
Explanation:The maximum daily dose of paracetamol in an adult is 4 grams. Doses greater than this can lead to hepatotoxicity and, less frequently, acute kidney injury. Early symptoms of paracetamol toxicity include nausea, vomiting, and abdominal pain, and usually settle within 24 hours. Symptoms of liver damage include right subcostal pain and tenderness, and this peaks 3 to 4 days after paracetamol ingestion. Other signs of hepatic toxicity include encephalopathy, bleeding, hypoglycaemia, and cerebral oedema.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 26
Incorrect
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Which JVP waveform correlates to atrial systole?
Your Answer:
Correct Answer: The a wave
Explanation:JVP Waveform in Cardiac Cycle Physiology: a wave Right atrial contraction causes atrial systole (end diastole). the c wave During right isovolumetric ventricular contraction, the tricuspid valve bulges into the right atrium, resulting in isovolumetric contraction (early systole). descent by x Rapid ventricular ejection (mid systole) is caused by a combination of right atrial relaxation, tricuspid valve downward movement during right ventricular contraction, and blood ejection from both ventricles. the v-wave Ventricular ejection and isovolumetric relaxation (late systole) occur as a result of venous return filling the right atrium. y lineage Ventricular filling occurs when the tricuspid valve opens, allowing blood to flow rapidly from the right atrium to the right ventricle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 27
Incorrect
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Which of the following best describes the order in which blood passes through the nephron?
Your Answer:
Correct Answer: Afferent arteriole→Glomerular capillary→Efferent arteriole→Peritubular capillary→Vasa recta
Explanation:The nephron’s blood flow is as follows:
Afferent arteriole – Glomerular capillary – Efferent arteriole – Peritubular capillary – Vasa recta – Afferent arteriole – Glomerular capillary – Efferent arteriole – Peritubular capillary – Vasa rectaThe kidney is the only vascular network in the body with two capillary beds. With arterioles supplying and draining the glomerular capillaries, higher hydrostatic pressures at the glomerulus are maintained, allowing for better filtration. A second capillary network at the tubules enables for secretion and absorption in the tubules, as well as concentrating urine.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 28
Incorrect
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Amoxicillin is used first line for all of the following infections EXCEPT for:
Your Answer:
Correct Answer: Cellulitis
Explanation:Amoxicillin is used first line for low to moderate severity community acquired pneumonia, exacerbations of chronic bronchitis, for acute otitis media, for acute sinusitis, for oral infections/dental abscess, for Listeria meningitis (in combination with another antibiotic), for infective endocarditis (in combination with another antibiotic) and for H. Pylori eradication (in combination with metronidazole/clarithromycin and a PPI). Flucloxacillin is used first line for acute cellulitis.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 29
Incorrect
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Which of the following nerves supply the superficial head of the flexor pollicis brevis muscle?
Your Answer:
Correct Answer: The recurrent branch of the median nerve
Explanation:The two heads of the flexor pollicis brevis usually differ in their innervation. The superficial head of flexor pollicis muscle receives nervous supply from the recurrent branch of the median nerve, whereas the deep head receives innervation from the deep branch of the ulnar nerve, derived from spinal roots C8 and T1.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 30
Incorrect
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Question 31
Incorrect
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All of the following are actions of insulin except:
Your Answer:
Correct Answer: Increased gluconeogenesis
Explanation:Major Actions of Insulin:
↑ Glucose uptake into cells
↑ Glycogenesis
↓ Glycogenolysis
↓ Gluconeogenesis
↑ Protein synthesis
↓ Protein degradation
↑ Fat deposition
↓ Lipolysis
↓ Ketoacid production
↑ K+ uptake into cellsMajor Actions of Glucagon:
↓ Glycogenesis
↑ Glycogenolysis
↑ Gluconeogenesis
↓ Fatty acid synthesis
↑ Lipolysis
↑ Ketoacid production -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 32
Incorrect
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A 58-year-old woman presents with symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that she has a full, plethoric aspect to her face, as well as significant supraclavicular fat pads, when you examine her. She has previously been diagnosed with Cushing's syndrome.
Cushing's syndrome is most commonly caused by which of the following?Your Answer:
Correct Answer: Iatrogenic administration of corticosteroids
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.
Iatrogenic corticosteroid injection is the most prevalent cause of Cushing’s syndrome. Cushing’s illness is the second most prevalent cause of Cushing’s syndrome. Cushing’s disease is distinct from Cushing’s syndrome in that it refers to a single cause of the illness, a pituitary adenoma that secretes high quantities of ACTH, which raises cortisol levels.
Cushing’s syndrome has several endogenous sources, including:
Cushing’s disease is caused by a pituitary adenoma.
Adrenal adenoma Ectopic corticotropin syndrome, e.g. small cell cancer of the lung
Adrenal carcinoma is a cancer of the adrenal gland.
Hyperplasia of the adrenal glands -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 33
Incorrect
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A 50-year-old man presents with headaches, lethargy, hypertension, and electrolyte disturbance. A diagnosis of primary hyperaldosteronism is made.
Which biochemical pictures would best support this diagnosis?
Your Answer:
Correct Answer: Hypokalaemic metabolic alkalosis
Explanation:When there are excessive levels of aldosterone outside of the renin-angiotensin axis, primary hyperaldosteronism occurs. High renin levels will lead to secondary hyperaldosteronism.
The classical presentation of hyperaldosteronism when symptoms are present include:
Hypokalaemia
Metabolic alkalosis
Hypertension
Normal or slightly raised sodium levels -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 34
Incorrect
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The percentage of patients with hepatitis B that develop chronic infection is about:
Your Answer:
Correct Answer: 10%
Explanation:With hepatitis B, about 90% of people will develop lifelong immunity after clearing the infection. Chronic hepatitis develops in about 10% of patients and this may be complicated by cirrhosis or hepatocellular carcinoma. There is a very high risk of chronic infection and hepatocellular carcinoma when there is congenital infection. The risk of this in healthy adults is only about 5%.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 35
Incorrect
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Excessive gastric acid output is detected in a patient with a history of recurrent stomach ulcers. It's possible that the patient has Zollinger-Ellison syndrome.
Which of the following statements about stomach acid is correct?Your Answer:
Correct Answer: The proton pump located in the canalicular membrane is vital to its secretion
Explanation:The stomach produces gastric acid, which is a digesting fluid. The stomach secretes about 2-3 litres every day. It is involved in tissue breakdown, the conversion of pepsinogen to active pepsin, and the creation of soluble salts with calcium and iron, and has a pH range of 1.5-3.5. It also serves as an immune system by destroying microbes.
The following substances are found in gastric acid:
Water
Acid hydrochloride
Pepsinogen
mucous
Intrinsic factorThe parietal cells in the proximal 2/3 (body) of the stomach release gastric acid. The concentration of hydrogen ions in parietal cell secretions is 1-2 million times that of blood. Chloride is released against both a concentration and an electric gradient, and active transport is required for the parietal cell to produce acid.
The following is how stomach acid is secreted:
1. Gastric acid secretion is dependent on the H+/K+ ATPase (proton pump) situated in the canalicular membrane. The breakdown of water produces hydrogen ions within the parietal cell. The hydroxyl ions produced in this reaction mix quickly with carbon dioxide to generate bicarbonate ions. Carbonic anhydrase is the enzyme that catalyses this process.
2. In return for chloride, bicarbonate is carried out of the basolateral membrane. The ‘alkaline tide’ occurs when bicarbonate is released into the bloodstream, resulting in a modest rise in blood pH. The parietal cell’s intracellular pH is maintained by this procedure. Conductance channels carry chloride and potassium ions into the lumen of canaliculi.
3. Through the action of the proton pump, hydrogen ions are pushed out of the cell and into the lumen in exchange for potassium; potassium is thus efficiently recycled.
4. The canaliculi accumulate osmotically active hydrogen ions, which creates an osmotic gradient across the membrane, allowing water to diffuse outward.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 36
Incorrect
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A 13-year-old male presents to the Emergency Department with a heavy nosebleed. His medical record shows that he was diagnosed with Haemophilia B as a child.
What is the mode of inheritance of this disease?Your Answer:
Correct Answer: X-linked recessive
Explanation:Deficiency of Factor IX causes Haemophilia B, and like the other Haemophilia’s, it has an X-linked recessive pattern of inheritance, affecting males born to carrier mothers.
Haemophilia B is the second commonest form of haemophilia and is rarer than haemophilia A. Haemophilia B is similar to haemophilia A but is less severe. You can distinguish the two disorders by specific coagulation factor assays.
The incidence of Haemophilia B is one-fifth of that of haemophilia A.
In laboratory findings, you get prolonged APTT, normal PT and low factor IX for Haemophilia B.
There is also a variation called Leyden, in which factor IX levels are below 1% until puberty, when they rise, potentially reaching as high as 40-60% of normal. This is thought to be due to the effects of testosterone at puberty.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 37
Incorrect
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An 85-year-old woman is brought in from her nursing home. She arrives in the Emergency Department and appears confused. The staff member from the nursing home accompanying her informs you that she takes a water tablet.
From her past medical history and records, you deduce that the water tablet is a loop diuretic.
Which of the following parts of a nephron does a loop diuretic act on?Your Answer:
Correct Answer: Ascending loop of Henlé
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 AcidLoop diuretics act on the apical membrane of the thick ascending loop of Henle and inhibit the Na-K-Cl cotransporter. This blocks the reabsorption of sodium and chloride and results in salt-water excretion. This relieves congestion and reduces oedema.
Other diuretics act on the following part of the nephron:
1. Thiazide diuretics – Na/Cl co-transporter in the distal convoluted tubule
2. Osmotic diuretics – PCT and the loop of Henle
3. Aldosterone antagonists – distal convoluted tubule
4. Carbonic anhydrase inhibitors – inhibit the carbonic anhydrase and act on proximal tubular cells -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 38
Incorrect
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Which of these drugs may reduce the efficacy of contraception?
Your Answer:
Correct Answer: Carbamazepine
Explanation:Antiepileptic medications such as carbamazepine (Tegretol), topiramate (Topamax), and phenytoin (Dilantin) are widely known for reducing the contraceptive effectiveness of OCPs.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 39
Incorrect
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You examine an elderly man who is experiencing chest pain. He doesn't recall all of his medications, but he does know that he takes a diuretic.
The enzyme carbonic anhydrase is inhibited by which of the following diuretics?Your Answer:
Correct Answer: Acetazolamide
Explanation:Acetazolamide is a non-competitive, reversible inhibitor of carbonic anhydrase found in the cytosol of cells and on the brush border of the proximal convoluted tubule. Bicarbonate and hydrogen ions are converted to carbonic acid by carbonic anhydrase, which then converts carbonic acid to carbon dioxide and water. As a result, acetazolamide reduces the availability of hydrogen ions, causing sodium and bicarbonate ions to accumulate in the renal tubule, resulting in diuresis.
The mechanism of action of the various types of diuretics is summarised below:1) Loop diuretics, e.g. furosemide, bumetanide
Act on the Na.K.2Cl co-transporters in the ascending loop of Henlé to inhibit sodium, chloride and potassium reabsorption.2) Thiazide diuretics, e.g. Bendroflumethiazide, hydrochlorothiazide
Act on the Na.Cl co-transporter in the distal convoluted tubule to inhibit sodium and chloride reabsorption.3) Osmotic diuretics, e.g. mannitol
Increases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect.4) Aldosterone antagonists, e.g. spironolactone
Acts in the distal convoluted tubule as a competitive aldosterone antagonist resulting in inhibition of sodium reabsorption and increasing potassium reabsorption.5) Carbonic anhydrase inhibitors, e.g. acetazolamide
Inhibit the enzyme carbonic anhydrase preventing the conversion of bicarbonate and hydrogen ions into carbonic acid. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 40
Incorrect
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A man presents to the emergency department with an injury that has damaged the opponens pollicis muscle.
Which of the following statements regarding the opponens pollicis muscle is considered correct?Your Answer:
Correct Answer: It flexes the first metacarpal bone at the carpometacarpal joint
Explanation:Opponens pollicis is a muscle of thenar eminence, it is triangular in shape and lies deep to flexor pollicis brevis and abductor pollicis brevis. It originates from the flexor retinaculum, tubercles of scaphoid and trapezium, abductor pollicis longus tendon.
Its insertion is in the radial side of the base of proximal phalanx of thumb. It is supplied by the median nerve (C8, T1). It receives blood supply from superficial arch.
It flexes the metacarpal bone medially across the palm, also rotating it medially, causing opposition, the palmar aspect of the terminal segment of thumb contacts the flexor aspects of any other digit.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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