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Question 1
Correct
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During anaerobic respiration, what is the net generation of ATP molecules:
Your Answer: 2
Explanation:In anaerobic respiration, two ATP molecules are produced for every glucose molecule, as opposed to the 38 molecules of ATP produced in aerobic respiration.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 2
Correct
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A patient has an elevated potassium level of 6.7 mmol/L. All of the following conditions may cause elevated potassium levels, except for which one?
Your Answer: Bartter’s syndrome
Explanation:Bartter’s syndrome is an autosomal recessive renal tubular disorder characterized by hypokalaemia, hypochloraemia, metabolic alkalosis, and hyperreninemia with normal blood pressure. The underlying kidney abnormality results in excessive urinary losses of sodium, chloride, and potassium.
Bartter’s syndrome does not cause an elevated potassium level, but instead causes a decrease in its concentration (hypokalaemia). The other choices are causes of hyperkalaemia or elevated potassium levels.
Renal failure, Addison’s disease (adrenal insufficiency), congenital adrenal hyperplasia, renal tubular acidosis (type 4), rhabdomyolysis, burns and trauma, tumour syndrome, and acidosis are non-drug causes of hyperkalaemia. On the other hand, drugs that can cause hyperkalaemia include ACE inhibitors, angiotensin receptor blockers, NSAIDs, beta-blockers, digoxin, and suxamethonium.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 3
Incorrect
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During quiet respiration, position of the right oblique fissure can be marked by a line drawn on the thoracic wall that:
Your Answer: Begins at the spinous process of T3, crosses the fifth intercostal space laterally and follows the contour of rib 5 anteriorly.
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 4
Correct
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Which of the following is NOT a typical cerebellar sign:
Your Answer: Hypertonia
Explanation:Hypotonia means decreased muscle tone. It can be a condition on its own, called benign congenital hypotonia, or it can be indicative of another problem where there is progressive loss of muscle tone, such as muscular dystrophy or cerebral palsy. It is usually detected during infancy. Hypotonia is characteristic of cerebellar dysfunction.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 5
Correct
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Regarding benzodiazepines, which of the following statements is INCORRECT:
Your Answer: Diazepam is a short-acting benzodiazepine.
Explanation:Diazepam is used to produce mild sedation with amnesia. It is a long-acting drug with active metabolites and a second period of drowsiness can occur several hours after its administration. Midazolam is a water-soluble benzodiazepine that is often used in preference to intravenous diazepam; recovery is faster than from diazepam, but may be significantly longer in the elderly, in patients with a low cardiac output, or after repeated dosing. Midazolam is associated with profound sedation when high doses are given intravenously or when it is used with certain other drugs.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
Correct
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Regarding haemoglobin, which of the following statements is CORRECT:
Your Answer: In degradation of haemoglobin, the haem group is split from the haemoglobin and converted to biliverdin and ultimately to bilirubin.
Explanation:Haemoglobin is composed of four polypeptide globin chains each with its own iron containing haem molecule. Haem synthesis occurs largely in the mitochondria by a series of biochemical reactions commencing with the condensation of glycine and succinyl coenzyme A under the action of the key rate-limiting enzyme delta-aminolevulinic acid (ALA) synthase. The globin chains are synthesised by ribosomes in the cytosol. Haemoglobin synthesis only occurs in immature red blood cells.
There are three types of haemoglobin in normal adult blood: haemoglobin A, A2 and F:
– Normal adult haemoglobin (HbA) makes up about 96 – 98 % of total adult haemoglobin, and consists of two alpha (α) and two beta (β) globin chains.Â
– Haemoglobin A2 (HbA2), a normal variant of adult haemoglobin, makes up about 1.5 – 3.5 % of total adult haemoglobin and consists of two α and two delta (δ) globin chains.
– Foetal haemoglobin is the main Hb in the later two-thirds of foetal life and in the newborn until approximately 12 weeks of age. Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin.Â
Red cells are destroyed by macrophages in the liver and spleen after , 120 days. The haem group is split from the haemoglobin and converted to biliverdin and then bilirubin. The iron is conserved and recycled to plasma via transferrin or stored in macrophages as ferritin and haemosiderin. An increased rate of haemoglobin breakdown results in excess bilirubin and jaundice. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 7
Incorrect
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Regarding cross-sectional studies, which of the following statements is CORRECT:
Your Answer: They are particularly suitable for estimating incidence of a disease.
Correct Answer: They are particularly suitable for estimating point prevalence.
Explanation:Cross-sectional studies aim to provide data about population health, normal ranges of biological parameters, and disease prevalence or severity by observing the entire population, or a representative subset, at a single point in time. Cross-sectional studies are relatively simple and quick to perform and can be used to study multiple outcomes, but are subject to confounding and recall bias and are not suitable for studying rare diseases. Cross-sectional studies cannot be used to assess causation or to consider trends over time.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 8
Correct
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A 70-year-old patient presents with a chronic digoxin overdose. She has vomited several times, is extremely tired, and her vision 'appears yellow,' according to her.
Which of the following is a reason for this patient's use of Digifab?Your Answer: Coexistent renal failure
Explanation:An antidote for digoxin overdose is digoxin-specific antibody (Digifab). It’s a lyophilized preparation of digoxin-immune ovine Fab immunoglobulin fragments that’s sterile, purified, and lyophilized. These fragments were extracted from the blood of healthy sheep that had been immunised with a digoxin derivative called digoxin-dicarboxymethoxylamine (DDMA), a digoxin analogue that contains the functionally important cyclopentaperhydrophenanthrene:lactone ring moiety coupled to keyhole limpet hemocyanin (KLH).
Digifab has a higher affinity for digoxin than digoxin does for its sodium pump receptor, which is thought to be the site of its therapeutic and toxic effects. When given to a patient who is intoxicated, Digifab binds to digoxin molecules, lowering free digoxin levels and shifting the equilibrium away from binding to receptors, reducing cardio-toxic effects. The kidney and reticuloendothelial system then clear the Fab-digoxin complexes.
The following summarises the indications for Digifab in acute and chronic digoxin toxicity:
Acute digoxin toxicity
Chronic digoxin toxicity
Cardiac arrest
Life-threatening arrhythmia
Potassium level > 5 mmol/l
>10 mg digoxin ingested (adult)
>4 mg digoxin ingested (child)
Digoxin level > 12 ng/ml
Cardiac arrest
Life-threatening arrhythmia
Significant gastrointestinal symptoms
Symptoms of digoxin toxicity -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 9
Incorrect
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Regarding hypernatraemia, which of the following statements is INCORRECT:
Your Answer: Diabetes insipidus causes hypernatraemia secondary to a pure water deficit.
Correct Answer: In acute severe hypernatraemia, seizures and intracranial vascular haemorrhage can occur as a result of brain cell lysis.
Explanation:Acute severe hypernatraemia is a medical emergency and requires inpatient management in a high dependency setting. Seizures and intracranial vascular haemorrhage as a result of brain cell crenation can occur. The cause is most commonly excessive water loss and the key aspect of treatment is aggressive fluid replacement (typically with normal saline as this is relatively hypotonic). If urine osmolality is low, diabetes insipidus (DI )should be considered and a trial of synthetic ADH given. In patients with known DI, it is essential to ensure synthetic ADH is given parenterally and that close fluid balance is observed.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 10
Incorrect
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A 30-year old male is brought to the emergency room after a terrible fall during a photoshoot. The patient reported falling on his right forearm. There is evident swelling and tenderness on the affected area, with notable weakness of the flexor pollicis longus muscle. Radiographic imaging showed a fracture on the midshaft of the right radius.
Which of the following nerves is most likely injured in the case above?Your Answer: The median nerve
Correct Answer: The anterior interosseous nerve
Explanation:Flexor pollicis longus receives nervous supply from the anterior interosseous branch of median nerve, derived from spinal roots C7 and C8.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 11
Incorrect
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A 52-year-old man develops pneumonia 3 days following an admission for investigation of chest pain. He has coarse left basal crackles and evidence of consolidation in the left lower lobe of chest X-ray. He has no known drug allergies.
According to the latest NICE guidelines, which of the following antibacterial agents would be most appropriate to prescribe in this case? Select ONE answer only.Your Answer: Piperacillin with tazobactam
Correct Answer: Co-amoxiclav
Explanation:Nosocomial infections are defined as those occurring within 48 hours of hospital admission, 3 days of discharge or 30 days of an operation. They affect 1 in 10 patients admitted to hospital. Annually, this results in 5000 deaths with a cost to the National Health Service of a billion pounds. On average, a patient with hospital acquired infection spent 2.5-times longer in hospital, incurring additional costs of £3000 more than an uninfected patient. Intensive care units (ICU) have the highest prevalence of hospital-acquired infections in the hospital setting.
The current recommendations by NICE and the BNF on the treatment of hospital acquired pneumonia are:
Early onset infection(less than 5 days after admission to hospital): co-amoxiclav or cefuroxime for 7 days
Late-onset infection(more than 5 days after admission to hospital): an antipseudomonal penicillin (e.g. piperacillin with tazobactam), a broad-spectrum cephalosporin (e.g. ceftazidime), or a quinolone (e.g. ciprofloxacin)
If the patient developed a hospital-acquired pneumonia within 5 days of admission – co-amoxiclav would be the most appropriate choice.
If the patient has developed a hospital-acquired pneumonia > 5 days after admission – ciprofloxacin would be the most appropriate choice from the list of options available. -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 12
Incorrect
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You are reviewing a patient complaining of loss of vision. Previous images shows a lesion at the optic chiasm. What type of visual field defect are you most likely to see in a lesion at the optic chiasm:
Your Answer: Homonymous hemianopia with macular sparing
Correct Answer: Bitemporal hemianopia
Explanation:A lesion at the optic chiasm will result in a bitemporal hemianopia.
A lesion of the optic nerve will result in ipsilateral monocular visual loss.
A lesion of the optic tract will result in a contralateral homonymous hemianopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 13
Incorrect
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An analytical cohort study aimed to determine a relationship between intake of dietary calcium and incidence of hip fractures among post-menopausal women. The following are the data obtained from the study:
No. of post-menopausal women who took Calcium: 500
No. of post-menopausal women who took Calcium and suffered a hip fracture: 10
No. of post-menopausal women who took placebo: 500
No. of post-menopausal women who took placebo and suffered a hip fracture: 25
Compute for the absolute risk reduction of a hip fracture.Your Answer: 0.4
Correct Answer: 0.03
Explanation:Absolute risk reduction (ARR) is computed as the difference between the absolute risk in the control group (ARC) and the absolute risk in the treatment group (ART).
ARR = ARC-ART
ARR = (25/500) – (10/500)
ARR = 0.03 -
This question is part of the following fields:
- Evidence Based Medicine
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Question 14
Incorrect
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Severe vomiting and diarrhoea were reported by a 25-year-old man. He's dehydrated and needs intravenous fluids to rehydrate. You give him cyclizine as part of his treatment.
What is cyclizine's main mechanism of action?Your Answer: 5-HT 3 receptor antagonism
Correct Answer: Antihistamine action
Explanation:Cyclizine is a piperazine derivative that functions as an antihistamine (H1-receptor antagonist). To prevent nausea and vomiting, it is thought to act on the chemoreceptor trigger zone (CTZ) and the labyrinthine apparatus. It has a lower antimuscarinic effect as well.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 15
Correct
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You are teaching a group of medical students about cardiovascular examination. You are discussing heart sounds and the cardiac cycle. Which of the following stages of the cardiac cycle occurs immediately after the aortic valve closes:
Your Answer: Isovolumetric relaxation
Explanation:Immediately after the closure of the semilunar valves, the ventricles rapidly relax and ventricular pressure decreases rapidly but the AV valves remain closed as initially the ventricular pressure is still greater than atrial pressure. This is isovolumetric relaxation. Atrial pressure continues to rise because of venous return, with the v wave of the JVP waveform peaking during this phase. Rapid flow of blood from the atria into the ventricles during the ventricular filling phase causes thethird heart sound, which is normal in children but, in adults, is associated with disease such as ventricular dilation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 16
Correct
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You review a 46-year-old woman who has recently been prescribed antibiotics for a urinary tract infection. She suffers from COPD and is currently prescribed salbutamol and Seretide inhalers, and Phyllocontin continus. Since starting the antibiotics, she has been experiencing nausea, vomiting and abdominal pain.
Which of the following antibiotics is she MOST LIKELY to have been prescribed for her UTI? Select ONE answer only .Your Answer: Ciprofloxacin
Explanation:Phyllocontin continus contains aminophylline (a mixture of theophylline and ethylenediamine), a bronchodilator used in the management of COPD and asthma.
This patient is exhibiting symptoms of theophylline toxicity, which may have been triggered by the prescription of the antibiotic. Quinolone antibiotics, such as ciprofloxacin and levofloxacin, and macrolide antibiotics, such as erythromycin, increase the plasma concentration of theophyllines and can lead to toxicity.
The drugs that commonly affect the half-life and the plasma concentration of theophylline are summarised in the table below:
Drugs increasing plasma concentration of theophylline
Drugs decreasing plasma concentration of theophylline
Calcium channel blockers, e.g. Verapamil
Cimetidine
Fluconazole
Macrolides, e.g. erythromycin
Quinolones, e.g. ciprofloxacin
Methotrexate
Barbiturates
Carbamazepine
Phenobarbitol
Phenytoin (and fosphenytoin)
Rifampicin
St. John’s wort -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 17
Correct
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Which of the following is an action of glucagon:
Your Answer: Stimulates glycogenolysis
Explanation:Glucagon is a peptide hormone that is produced and secreted by alpha cells of the islets of Langerhans, which are located in the endocrine portion of the pancreas. The main physiological role of glucagon is to stimulate hepatic glucose output, thereby leading to increases in glycaemia. It provides the major counter-regulatory mechanism to insulin in maintaining glucose homeostasis.
Hypoglycaemia is the principal stimulus for the secretion of glucagon but may also be used as an antidote in beta-blocker overdose and in anaphylaxis in patients on beta-blockers that fail to respond to adrenaline.
Glucagon then causes:
Glycogenolysis
Gluconeogenesis
Lipolysis in adipose tissue
The secretion of glucagon is also stimulated by:
Adrenaline
Cholecystokinin
Arginine
Alanine
Acetylcholine
The secretion of glucagon is inhibited by:
Insulin
Somatostatin
Increased free fatty acids
Increased urea productionGlycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released by this process is used to form ATP and NADH. Glycolysis is inhibited by glucagon, and glycolysis and gluconeogenesis are reciprocally regulated so that when one cell pathway is activated, the other is inactive and vice versa.
Glucagon has a minor effect of enhancing lipolysis in adipose tissue. Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into glycerol and free fatty acids. It makes fatty acids available for oxidation.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 18
Correct
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A 76-year-old man presents with complaints of double vision. Upon physical examination, it was observed that he exhibits left-sided hemiplegia and left-sided loss of joint position sense, vibratory sense and discriminatory touch. In addition, he has the inability to abduct his right eye and is holding his head towards the right side. A CT scan was ordered and showed that he has suffered a right-sided stroke.
Branches of which of the following arteries are most likely implicated in the case?Your Answer: Basilar artery
Explanation:Inferior medial pontine syndrome, also known as Foville syndrome, is one of the brainstem stroke syndromes which occurs when there is infarction of the medial inferior aspect of the pons due to occlusion of the paramedian branches of the basilar artery.
It is characterized by ipsilateral sixth nerve palsy, facial palsy, contralateral hemiparesis, contralateral loss of proprioception and vibration, ipsilateral ataxia, ipsilateral facial weakness, and lateral gaze paralysis and diplopia.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 19
Correct
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The common bile duct drains into the duodenum in which of the following regions:
Your Answer: Second part of the duodenum
Explanation:As the common bile duct descends, it passes posterior to the first part of the duodenum before joining with the pancreatic duct from the pancreas, forming the hepatopancreatic ampulla (ampulla of Vater) at the major duodenal papilla, located in the second part of the duodenum. Surrounding the ampulla is the sphincter of Oddi, a collection of smooth muscle which can open to allow bile and pancreatic fluid to empty into the duodenum.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 20
Incorrect
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Regarding antacids, which of the following statements is CORRECT:
Your Answer: Antacids are best taken regularly each morning for maximum symptom control.
Correct Answer: Antacids are contraindicated in hypophosphataemia.
Explanation:Antacids are contraindicated in hypophosphataemia. Liquid preparations are more effective than tablet preparations. Magnesium-containing antacids tend to be laxative whereas aluminium-containing antacids tend to be constipating. Antacids are best taken when symptoms occur or are expected, usually between meals and at bedtime. Antacids should preferably not be taken at the same time as other drugs since they may impair absorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 21
Correct
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The Auerbach's plexus is a set of ganglia that controls peristalsis and is located in the gut wall.
Auerbach's plexus is located in which layer of the gut wall?Your Answer: Muscular layer
Explanation:The Auerbach’s plexus, also known as the myenteric plexus, is a collection of ganglia that controls peristalsis and is located in the gut wall.
In the muscular layer of the wall, it is located between the circular and longitudinal muscle layers. It is a linear network of linked neurons that runs the length of the gastrointestinal system. The myenteric plexus generates an increase in gut wall tone and the strength of rhythmical contractions when stimulated.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 22
Correct
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Regarding Clostridium perfringens, which of the following statements is CORRECT:
Your Answer: It can cause exotoxin-mediated food poisoning.
Explanation:Clostridium perfringens is an obligate anaerobe and has exotoxin mediated effects. It is the most common cause of gas gangrene. C. perfringens is also implicated in food poisoning, cellulitis, enteritis necrotican (life-threatening infection involving ischaemic necrosis of the jejunum), and rarely, CNS infections such as meningitis and encephalitis.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 23
Correct
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Which of the following clinical features is NOT a typical feature of haemolytic anaemias:
Your Answer: Angular cheilitis
Explanation:Features include:
Anaemia
Jaundice (caused by unconjugated bilirubin in plasma, bilirubin is absent from urine)
Pigment gallstones
Splenomegaly
Ankle ulcers
Expansion of marrow with, in children, bone expansion e.g. frontal bossing in beta-thalassaemia major
Aplastic crisis caused by parvovirus -
This question is part of the following fields:
- Haematology
- Pathology
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Question 24
Incorrect
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You've been summoned to your Emergency Department resuscitation area to see a patient. You consider giving him an atropine shot because he is severely bradycardic.
Which of the following statements about the use of atropine is correct?Your Answer: It is recommended in the treatment of haemodynamically stable bradycardias
Correct Answer: It blocks the effects of the vagus nerve on both the SA and AV nodes
Explanation:At muscarinic receptors, atropine blocks the action of the parasympathetic neurotransmitter acetylcholine. As a result, it inhibits the vagus nerve’s effects on both the SA and AV nodes, increasing sinus automaticity and facilitating AV node conduction.
At muscarinic receptors, atropine blocks the action of the parasympathetic neurotransmitter acetylcholine. As a result, it inhibits the vagus nerve’s effects on both the SA and AV nodes, increasing sinus automaticity and facilitating AV node conduction.
The most common cause of asystole during cardiac arrest is primary myocardial pathology, not excessive vagal tone, and there is no evidence that atropine is helpful in the treatment of asystole or PEA. As a result, it is no longer included in the ALS algorithm’s non-shockable section. Atropine is most commonly used in the peri-arrest period. It is used to treat bradycardia (sinus, atrial, or nodal) or AV block when the patient’s haemodynamic condition is compromised by the bradycardia.
If any of the following adverse features are present, the ALS bradycardia algorithm recommends a dose of 500 mcg IV:
Shock
Syncope
Myocardial ischaemia
Heart failureAtropine is also used for the following purposes:
Topically as a cycloplegic and mydriatic to the eyes
To cut down on secretions (e.g. in anaesthesia)
Organophosphate poisoning is treated with
Atropine’s side effects are dose-dependent and include:
Mouth is parched
Vomiting and nausea
Vision is hazy
Retention of urine
Tachyarrhythmias
It can also cause severe confusion and hallucinations in patients, especially the elderly. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 25
Incorrect
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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: The axillary nerve
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 26
Correct
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A 5-year-old girl is brought into the Paediatric ER for acute seizures. She has been convulsing for the past 18 minutes now and was already two doses of lorazepam in the ambulance. Now, you prepare a phenytoin infusion to abolish the seizures.
According to the APLS algorithm, what dose of phenytoin is advised for a convulsing child at this stage?Your Answer: 20 mg/kg over 20 minutes
Explanation:Advanced paediatric life support (APLS) recommends phenytoin as the first choice for second-line anticonvulsant in a patient that continues to seize ten minutes after the second dose of the first-line anticonvulsant (benzodiazepine). (step 3 of the APLS algorithm)
The recommended dose of phenytoin infusion is up at 20 mg/kg over 20 minutes. If the patient has already taken phenytoin as maintenance therapy or is allergic to phenytoin, then a phenobarbitone infusion should be set up at 20 mg/kg over 30-60 minutes.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 27
Incorrect
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Which of the following is most likely affected in De Quervain's tenosynovitis?
Your Answer: Extensor pollicis longus
Correct Answer: Extensor pollicis brevis
Explanation:De Quervain tenosynovitis is named after the Swiss surgeon, Fritz de Quervain, who first described it in 1895. It is a condition which involves tendon entrapment affecting the first dorsal compartment of the wrist. With this condition thickening of the tendon sheaths around the abductor pollicis longus and extensor pollicis brevis develops where the tendons pass in through the fibro-osseous tunnel located along the radial styloid at the distal wrist. Pain is exacerbated by thumb movement and radial and ulnar deviation of the wrist.
The estimated prevalence of de Quervain tenosynovitis is about 0.5% in men and 1.3% in women with peak prevalence among those in their forties and fifties. It may be seen more commonly in individuals with a history of medial or lateral epicondylitis. Bilateral involvement is often reported in new mothers or child care providers in whom spontaneous resolution typically occurs once lifting of the child is less frequent.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 28
Correct
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You examine a patient's blood tests and discover that her electrolyte levels are abnormal.
Which of the following is the major extracellular cation?Your Answer: Sodium
Explanation:Electrolytes are compounds that may conduct an electrical current and dissociate in solution. Extracellular and intracellular fluids contain these chemicals. The predominant cation in extracellular fluid is sodium, whereas the major anion is chloride. Potassium is the most abundant cation in the intracellular fluid, while phosphate is the most abundant anion. These electrolytes are necessary for homeostasis to be maintained.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 29
Correct
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Which of the following antibiotics may be used for malaria prophylaxis:
Your Answer: Doxycycline
Explanation:Doxycycline may be used for malaria prophylaxis and as an adjunct to quinine in the treatment of Plasmodium falciparum malaria.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 30
Incorrect
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1-alpha-hydroxylase is a cytochrome p450 enzyme that is involved in the production of vitamin D's hormonally active metabolite.
Which of the following promotes the activity of 1-alpha-hydroxylase?Your Answer: Calcitonin
Correct Answer: Parathyroid hormone
Explanation: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 promoted by parathyroid hormone or hypophosphatemia.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 31
Incorrect
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Clostridium difficile primarily causes which of the following infectious diseases:
Your Answer: Gas gangrene
Correct Answer: Pseudomembranous colitis
Explanation:Clostridium difficile causes pseudomembranous colitis, an acute inflammatory diarrhoeal disease and an important cause of morbidity and mortality in hospitals. Gas gangrene is primarily caused by Clostridium perfringens. Tetanus is caused by Clostridium tetani. Toxic shock syndrome may be caused by Staphylococcus aureus or Streptococcus pyogenes. Necrotising fasciitis is most commonly caused by Streptococcus pyogenes but has a multitude of causes.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 32
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 33
Incorrect
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Mast cells play a significant part in which of the following?
Your Answer: Neutralising bacterial toxins
Correct 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 34
Incorrect
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A 27 year old woman presents to ED having sustained a deep laceration to the dorsum of her ring finger whilst cooking. Her proximal interphalangeal joint is fixed in flexion and the distal interphalangeal joint is hyperextended. Which of the following structures in the digit has most likely been injured:
Your Answer: Terminal insertion of the extensor tendon
Correct Answer: Insertion of the central slip of the extensor tendon
Explanation:Damage to the central slip of the extensor digitorum tendon would result in loss of extension at the proximal interphalangeal joint resulting in a fixed flexion deformity of this joint, and hyperextension of the distal interphalangeal joint due to a loss of balancing forces. This is called the Boutonniere deformity.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 35
Incorrect
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An analytical cohort study is done to compare the relationship between omega 3 intake and occurrence of myocardial infarction (MI) among males aged over 65 years. The following are the data from the study:
No. of subjects taking placebo: 100 men
No. of subjects taking placebo who suffered an MI: 15 men
No. of subjects taking omega 3: 100 men
No. of subjects taking omega 3 who suffered an MI: 5 men
Compute for the absolute risk in the treatment (omega 3) group.Your Answer: 0.15
Correct Answer: 0.05
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.
AR = 5/100 = 0.05
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This question is part of the following fields:
- Evidence Based Medicine
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Question 36
Correct
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A 52-year-old patient requires procedural sedation for DC cardioversion of atrial fibrillation. You plan on using propofol as the sedative agent.
Propofol works as a result of action on what type of receptor? Select ONE answer only.Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Propofol (2,6-diisopropylphenol) is a short-acting phenol derivative that is primarily used for the induction of anaesthesia.
Its mechanism of action is unclear but is thought to act by potentiating the inhibitory neurotransmitters GABA and glycine, which enhances spinal inhibition during anaesthesia.
The dose for induction of anaesthesia is 1.5-2.5mg/kg. The dose for maintenance of anaesthesia is 4-12 mg/kg/hour. Following intravenous injection, propofol acts within 30 seconds and its duration of action is 5-10 minutes.
Propofol produces a 15-25% decrease in blood pressure and systemic vascular resistance without a compensatory increase in heart rate. It is negatively inotropic and decreases cardiac output by approximately 20%.
The main side effects of propofol are:
Pain on injection (in up to 30%)
Hypotension
Transient apnoea
Hyperventilation
Coughing and hiccough
Headache
Thrombosis and phlebitis -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 37
Incorrect
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A 32-year-old woman with a history of bipolar disorder exhibits lithium toxicity symptoms.
Which of the following is the MOST LIKELY feature to be present?Your Answer: Reduced muscle tone
Correct Answer: Clonus
Explanation:Lithium toxicity manifests itself in the following ways:
Ataxia
Clonus
Coma
Confusion
Convulsions
Diarrhoea
Increased muscle tone
Nausea and vomiting
Nephrogenic diabetes insipidus
Renal failure
Tremor -
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 38
Correct
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A newborn baby is born by vaginal delivery to a mother who has a Chlamydia infection and who is started on treatment after the delivery. The neonate subsequently develops an infection also.
Which one of these is the most common neonatal manifestation of Chlamydia trachomatis infection?Your Answer: Conjunctivitis
Explanation:Conjunctivitis is the most common neonatal manifestation of Chlamydia trachomatis infection. The second commonest neonatal manifestation is pneumonia
Ophthalmia neonatorum refers to any conjunctivitis in the newborn period, irrespective of causative organism. Presently, chlamydia is the single most common cause, accounting for up to 40% of cases. Ophthalmia neonatorum caused by chlamydia typically presents 5 to 14 days after birth with unilateral or bilateral watery discharge that progressively becomes more copious and purulent. There is no associated risk of ulceration and perforation, and the eyes are less inflamed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 39
Incorrect
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You suspected typhoid disease in a patient who had recently returned from South America and presented to the emergency department with fever, constipation, and a rose spot rash. Which of the following antibiotics will be administered to this patient?
Your Answer: Clarithromycin
Correct Answer: Cefotaxime
Explanation:Typhoid fever, often known as enteric fever, is a potentially fatal multi-systemic sickness caused predominantly by Salmonella enterica serotype typhi and, to a lesser extent, paratyphi A, B, and C.
Cefotaxime is the first-line treatment for typhoid fever (or ceftriaxone). In cases of mild or moderate sickness caused by multiresistant pathogens, azithromycin is an option. If the bacterium is sensitive, ciprofloxacin is an option.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 40
Incorrect
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A patient suffers a lower limb fracture that causes damage to the nerve that innervates peroneus longus.
Peroneus longus receives its innervation from which of the following nerves? Select ONE answer only.Your Answer: Deep peroneal nerve
Correct Answer: Superficial peroneal nerve
Explanation:Peroneus brevis is innervated by the superficial peroneal nerve.
Peroneus longus is innervated by the superficial peroneal nerve.
Peroneus tertius is innervated by the deep peroneal nerve. -
This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 41
Correct
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Platelet alpha granules release which of the following?
Your Answer: Von Willebrand factor (VWF)
Explanation:There are three types of storage granules contained in platelets. These are dense granules which contain the following:
-ATP
-ADP
-serotonin and calcium alpha granules containing clotting factors
-von Willebrand factor (VWF)
-platelet-derived growth factor (PDGF)
– other proteins lysosomes containing hydrolytic enzymes. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 42
Correct
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A 18 year old male presents to the GP with painless asymmetrical cervical lymphadenopathy. Histological examination of a biopsied lymph node demonstrates Reed-Sternberg cells. What is the most likely diagnosis:
Your Answer: Hodgkin lymphoma
Explanation:Hodgkin’s lymphoma is a malignant tumour of the lymphatic system that is characterised histologically by the presence of Reed-Sternberg cells (multinucleated giant cells). The peak incidence is in young adults aged 20-35, and there is a slight male predominance.
The following are recognised risk factors for Hodgkin’s lymphoma:
Male gender
Age 20-35
Positive family history
Epstein-Barr virus infection
Immunosuppression including HIV infection
Prolonged use of human growth hormone
Most patients present with an enlarged, but otherwise asymptomatic lymph node. The most commonly affected lymph nodes are in the supraclavicular and lower cervical areas. Other common clinical features include shortness of breath and chest discomfort secondary to mediastinal mass. Mediastinal masses are sometimes discovered as incidental findings on routine chest X-rays. Approximately 30% of patients with Hodgkin’s lymphoma develop splenomegaly.
‘B’ symptoms occur in approximately 25% of patients. The ‘B’ symptoms of Hodgkin’s lymphoma are:
Fever (>38ºC)
Night sweats
Weight loss (>10% over 6 months)
Pain after alcohol consumption is a pathognomonic sign of Hodgkin’s lymphoma, it is, however, not a ‘B’ symptom. It is rare though, only occurring in 2-3% of patients with Hodgkin’s lymphoma.The Ann Arbour clinical staging is as follows:
Stage I: one involved lymph node group
Stage II two involved lymph node groups on one side of the diaphragm
Stage III: lymph node groups involved on both sides of the diaphragm
Stage IV: Involvement of extra-nodal tissues, such as the liver or bone marrow
Diagnosis is made by lymph node biopsy, which should be taken from a sufficiently large specimen or excisional biopsy, as opposed to a fine needle biopsy. The Reed-Sternberg cell is the most useful diagnostic feature. This is a giant cell with twin mirror-image nuclei and prominent ‘owl’s eye’ nucleoli.
The Reed-Sternberg cell of Hodgkin’s Lymphoma
Histological typing depends upon the other cells within the diseased tissue. Nodular sclerosing is the most common type of Hodgkin’s lymphoma. Lymphocyte-depleted and lymphocyte-predominant are rare subtypes.
The majority of cases can be successfully treated, and unlike many other malignancies even if the first-line treatment fails, a cure can often be achieved with second-line therapies. Stage 1 Hodgkin’s lymphoma is usually treated with radiotherapy alone, but more advanced stages require combination chemotherapy. In localised disease treated with irradiation, there is a 5-year survival rate of greater than 80%. In disseminated disease treated with chemotherapy, the 5-year survival falls to around 50%. Overall, a 5-year survival of >70% should be achieved. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 43
Correct
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Beta cells of the endocrine pancreas produce which of the following hormones:
Your Answer: Insulin
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 44
Incorrect
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A 7-days-old neonate is taken to the emergency department. She's pyretic, lethargic, and unresponsive, and her fontanelle has bulged. Antibiotics are started, and a lumbar puncture reveals Gram-negative rods. Which pathogen is most likely to be the cause:
Your Answer: Neisseria meningitidis
Correct Answer: Escherichia coli
Explanation:Among neonates, group B streptococci (GBS) are the most commonly identified causes of bacterial meningitis, implicated in roughly 50% of all cases. Escherichia coli(Gram-negative rods) accounts for another 20%. Thus, the identification and treatment of maternal genitourinary infections is an important prevention strategy.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 45
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 46
Correct
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Detection of urinary Bence-Jones protein would be most suggestive of which of the following malignancies:
Your 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 47
Incorrect
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The proximal convoluted tubule (PCT) is the first part of the renal tubule and lies in the renal cortex. The bulk of reabsorption of solute occurs is the PCT and 100% of glucose is reabsorbed here.
Which of the following is the mechanism of glucose reabsorption in the PCT?Your Answer: Facilitated diffusion
Correct Answer: Secondary active transport
Explanation:Glucose reabsorption occurs exclusively in the proximal convoluted tubule by secondary active transport through the Na.Glu co-transporters, driven by the electrochemical gradient for sodium.
The co-transporters transport two sodium ions and one glucose molecule across the apical membrane, and the glucose subsequently crosses the basolateral membrane by facilitated diffusion. -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 48
Correct
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You are about to perform a blood test on a patient suspected of having systemic lupus erythematosus. Which antibodies will indicate a positive result of systemic lupus erythematosus?
Your Answer: Anti-nuclear antibodies
Explanation:Antinuclear antibodies (ANA) are autoantibodies to the cells’ nucleus.
The ANA test is the most sensitive diagnostic test for verifying the disease’s diagnosis.
Other autoantibodies that may be found in SLE patients include rheumatoid factor, antiphospholipid antibodies, and antimitochondrial antibodies.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 49
Correct
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You review a 56-year-old man who has recently been prescribed antibiotics for a chest infection. He suffers from COPD and is currently prescribed salbutamol and Seretide inhalers, and Phyllocontin continus. Since starting the antibiotics, he has been experiencing nausea, vomiting and abdominal pain.
Which of the following antibiotics is he MOST LIKELY to have been prescribed for his chest infection? Select ONE answer only .Your Answer: Levofloxacin
Explanation:Phyllocontin continus contains aminophylline (a mixture of theophylline and ethylenediamine), a bronchodilator used in the management of COPD and asthma.
This patient is exhibiting symptoms of theophylline toxicity, which may have been triggered by the prescription of the antibiotic. Quinolone antibiotics, such as ciprofloxacin and levofloxacin, and macrolide antibiotics, such as erythromycin, increase the plasma concentration of theophyllines and can lead to toxicity.
The drugs that commonly affect the half-life and the plasma concentration of theophylline are summarised in the table below:
Drugs increasing plasma concentration of theophylline
Drugs decreasing plasma concentration of theophylline
Calcium channel blockers, e.g. Verapamil
Cimetidine
Fluconazole
Macrolides, e.g. erythromycin
Quinolones, e.g. ciprofloxacin
Methotrexate
Barbiturates
Carbamazepine
Phenobarbitol
Phenytoin (and fosphenytoin)
Rifampicin
St. John’s wort -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 50
Incorrect
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Regarding local anaesthetics, which of the following statements is INCORRECT:
Your Answer: Bupivacaine takes up to 30 minutes for a full effect.
Correct Answer: Adrenaline should be used in digital nerve blocks to create a bloodless field.
Explanation:It is not advisable to give adrenaline/epinephrine with a local anaesthetic injection in digits or appendages because of the risk of ischaemic necrosis.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
