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Question 1
Correct
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Question 2
Incorrect
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Regarding diuretics, which of the following statements is CORRECT:
Your Answer: Spironolactone may cause hypokalaemia through increasing potassium secretion in the distal nephron.
Correct Answer: Carbonic anhydrase inhibitors have their effect by inhibiting bicarbonate reabsorption.
Explanation:Carbonic anhydrase inhibitors e.g. acetazolamide block the reaction of carbon dioxide and water and so prevent Na+/H+exchange and bicarbonate reabsorption. The increased bicarbonate levels in the filtrate oppose water reabsorption. Proximal tubule sodium reabsorption is also reduced because it is partly dependent on bicarbonate reabsorption.
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This question is part of the following fields:
- Physiology
- Renal
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Question 3
Incorrect
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Regarding the heart sounds in the cardiac cycle, which of the following statements is INCORRECT:
Your Answer: Inspiration delays closure of the pulmonary valve and thus causes splitting of the second heart sound.
Correct Answer: The third heart sound is caused by filling of an abnormally stiff ventricle in atrial systole.
Explanation:Heart Sound – Phase of Cardiac Cycle – Mechanical Event:
First heart sound – Start of systole – Caused by closure of the atrioventricular (mitral & tricuspid) valves
Second heart sound – End of systole – Caused by closure of the semilunar (aortic and pulmonary) valves
Third heart sound – Early diastole – Caused by rapid flow of blood from the atria into the ventricles during the ventricular filling phase
Fourth heart sound – Late diastole – Caused by filling of an abnormally stiff ventricle in atrial systole -
This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 4
Correct
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Which of the following is NOT a contraindication to the use of diazepam:
Your Answer: Acute alcohol withdrawal
Explanation:Benzodiazepines are used to treat symptoms in patients with acute alcohol withdrawal syndrome.
Benzodiazepines are contraindicated in:
Respiratory depression
Marked neuromuscular respiratory weakness, such as unstable myasthenia gravis
Obstructive sleep apnoea syndrome (symptoms may be aggravated)
Severe hepatic impairment (the elimination half-life of diazepam may be prolonged; increased risk of coma)
Phobic or obsessional states, chronic psychosis or hyperkinesis (paradoxical reactions may occur). -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 5
Incorrect
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You intend to suture a hand wound with plain 1 percent lidocaine.
In 1 mL of plain 1 percent lidocaine solution, how much lidocaine hydrochloride is there?Your Answer: 10 mcg lidocaine hydrochloride
Correct Answer: 10 mg lidocaine hydrochloride
Explanation:10 mg of lidocaine hydrochloride is contained in each 1 mL of plain 1 percent lidocaine solution.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
Incorrect
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The Meissner’s plexus acts as the main control for gastrointestinal secretion and local blood flow within the gut.
The Meissner’s plexus lies in which layer of the gut wall?Your Answer: Subserosa
Correct Answer: Submucosa
Explanation:The Meissner’s plexus (submucosal plexus), an enteric nervous plexus, acts as the main control for gastrointestinal secretion and local blood flow within the gut.
It is located in the submucosal layer on the inner surface of the muscularis externa.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 7
Correct
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You review the arterial blood gas (ABG) of a patient with lactic acidosis.
Which SINGLE statement regarding lactic acidosis is true?Your Answer: Type A lactic acidosis is typically due to tissue hypoxia
Explanation:Lactic acidosis is defined as a pH <7.35 and a lactate >5 mmol/L. It is a common finding in critically ill patients and is often associated with other serious underlying pathologies. The anion gap is raised in lactic acidosis.
There are major adverse consequences of severe acidaemia, which affect all body systems, and there is an associated increase in mortality of critically ill patients with a raised lactate. The mortality associated with lactic acidosis despite full supportive treatment remains at 60-90%.
Acquired lactic acidosis is classified into two subtypes:
Type A is due to tissue hypoxia
Type BÂ is due to non-hypoxic processes affecting the production and elimination of lactate
Lactic acidosis can be extreme after a seizure but usually resolves spontaneously within a few hours.
Left ventricular failure typically results in tissue hypoperfusion and a type A lactic acidosis.
Some causes of type A and type B lactic acidosis are shown below:
Type A lactic acidosis
Type B lactic acidosis
Shock (including septic shock)
Left ventricular failure
Severe anaemia
Asphyxia
Cardiac arrest
CO poisoning
Respiratory failure
Severe asthma and COPD
Regional hypoperfusion
Renal failure
Liver failure
Sepsis (non-hypoxic sepsis)
Thiamine deficiency
Alcoholic ketoacidosis
Diabetic ketoacidosis
Cyanide poisoning
Methanol poisoning
Biguanide poisoning -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 8
Incorrect
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A 15-year-old male is admitted to a rehabilitation centre with a history of multiple strokes, myopathy and learning disabilities since childhood. He is under the care of a multidisciplinary team, and his genetic testing reports show the presence of a mitochondrial disorder.
Which one of the following diseases does this patient most likely have?Your Answer: Glucose-6-phosphate dehydrogenase deficiency
Correct Answer: MELAS
Explanation:Mitochondrial diseases are a group of disorders caused by dysfunctional mitochondria. Most cases are maternally inherited, as we inherit our mitochondrial DNA from our mothers only, although mutations in nuclear DNA cause some cases.
Examples of Mitochondrial Diseases include:
1. Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS)
2. Mitochondrial epilepsy with ragged red fibres (MERRF)
3. Leber’s hereditary optic neuropathy (LHON)
4. Diabetes mellitus and deafness (DAD)
5. Neuropathy, ataxia, retinitis pigmentosa, and ptosis (NARP)
6. Leigh syndrome (subacute sclerosing encephalopathy).Red-green colour blindness and G6PD deficiency have an X-linked recessive pattern of inheritance.
Tay-Sachs Disease and spinal muscular atrophy have an autosomal recessive pattern of inheritance.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 9
Correct
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Regarding the brachioradialis muscle, which of the following statements is true?
Your Answer: It assists with supination of the forearm at the radioulnar joints
Explanation:Brachioradialis is a fusiform muscle located in the lateral part of the posterior forearm. Along with extensor carpi radialis brevis and extensor carpi radialis longus, it comprises the radial group of forearm muscles, which belong to the superficial layer of posterior forearm muscles. Although anatomically part of the posterior forearm muscles, which are known to be forearm extensors, brachioradialis’ fibre orientation enables it to rather flex the forearm, and aids in supination of the forearm at the radioulnar joint.
The brachioradialis muscle originates from the upper two-thirds of the lateral supracondylar ridge of humerus and the anterior surface of the lateral intermuscular septum of the arm. It slides over the lateral surface of the elbow joint, entering the anterolateral cubital area. The muscle fibres course inferiorly down the radial part of the anterior forearm, forming a thick tendon in approximately the middle of the forearm. This tendon then traverses the remainder of the forearm, inserting near the wrist, just proximal to the styloid process of radius.
Brachioradialis is innervated by the radial nerve (from the root values C5-C6) that stems from the posterior cord of the brachial plexus. Blood supply to the brachioradialis muscle comes from branches of the radial artery, radial recurrent artery and the radial collateral branch of the deep brachial artery.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 10
Correct
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Bordetella pertussis causes which of the following infectious diseases:
Your Answer: Whooping cough
Explanation:Bordetella pertussis causes whooping cough. Acute bronchiolitis is typically caused by respiratory syncytial virus. Parainfluenza virus is the most common cause of croup. Acute epiglottitis is usually caused by an infection with Haemophilus influenzae type b (Hib) bacteria. The common cold may be caused by a number of viruses including rhinovirus and coronavirus.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 11
Incorrect
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You're a member of the cardiac arrest team, and you're helping to resuscitate an elderly gentleman who had collapsed at home. The team leader requests that you administer an adrenaline shot.
Which of the following statements about adrenaline is FALSE?Your Answer: It has approximately equal activity at both alpha- and beta receptors
Correct Answer: The IM dose in anaphylaxis is 1 ml of 1:1000
Explanation:Adrenaline (epinephrine) is a sympathomimetic amine that binds to alpha- and beta-adrenergic receptors and acts as an agonist. It is active at both alpha and beta receptors in roughly equal amounts.
When taken orally, it becomes inactive. Subcutaneous absorption is slower than intramuscular absorption. In cardiac arrest, it is well absorbed from the tracheal mucosa and can be given through an endotracheal tube.
At the adrenergic synapse, catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) metabolise it primarily. The inactive products are then passed through the kidneys and excreted in the urine.
In adult cardiac arrest, the IV dose is 1 mg, which is equal to 10 ml of 1:10000 or 1 ml of 1:1000. In anaphylaxis, the IM dose is 0.5 ml of 1:1000. (500 mcg).
In open-angle glaucoma, adrenaline causes mydriasis and lowers pressure.
Adrenaline is used in cardiopulmonary resuscitation, the treatment of severe croup, and the emergency management of acute allergic and anaphylactic reactions (as a nebuliser solution).
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 12
Correct
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Question 13
Incorrect
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A patient who has a nerve injury has sparing of the upper half of the orbicularis oculi muscle but not the lower half. Which branch of the facial nerve supplies the lower half of the orbicularis oculi?
Your Answer: Temporal branch
Correct Answer: Zygomatic branch
Explanation:The facial nerve divides into five terminal branches once in the parotid gland.
1. The temporal branch innervates muscles in the temple, forehead and supraorbital areas.
2. The zygomatic branch innervates muscles in the infraorbital area, the lateral nasal area and the upper lip.
3. The buccal branch innervates muscles in the cheek, the upper lip and the corner of the mouth.
4. The marginal mandibular branch innervates muscles of the lower lip and chin.
5. The cervical branch innervates the platysma muscle. -
This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 14
Correct
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Diabetic ketoacidosis is characterised by which of the following:
Your Answer: Hyperglycaemia, ketonaemia and acidosis
Explanation:DKA is characterised by the biochemical triad:
1. Hyperglycaemia (> 11 mmol/L)
2. Ketonaemia (> 3 mmol/L)
3. Acidosis (pH < 7.3 +/- HCO3 < 15 mmol/L) -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 15
Incorrect
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A 25-year-old guy who has had a knee-high plaster cast on his left leg for the past 5 weeks arrives at the emergency department complaining of numbness on the dorsum of his left foot and an inability to dorsiflex or evert his foot. You know that his symptoms are due to fibular nerve compression. Where is the fibular nerve located?
Your Answer: Popliteal fossa
Correct Answer: Neck of fibula
Explanation:Dorsiflexion and eversion of the foot are innervated by the deep fibular nerve and the superficial fibular nerve, respectively.
The common fibular nerve runs obliquely downward along the lateral border of the popliteal fossa (medial to the biceps femoris) before branching at the neck of the fibula.
Thus, it is prone to being affected during an impact injury or fracture to the bone or leg. Casts that are placed too high can also compress the fibular nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 16
Incorrect
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A 60-year-old female presents with fatigue, easy bruising and repeated chest and skin infections for five months. She also complains about several episodes of nosebleeds over the last few days without any history of trauma.
Her complete blood count shows the following results:
Hb 9 g/dl
Total leukocyte count: 2.5x10^9/L, 1100 neutrophils/ųL
MCV 100
platelet count of 90,000/ųL.
Which one of the following conditions does this patient most likely have?Your Answer: Chronic lymphocytic leukaemia
Correct Answer: Myelodysplastic syndrome
Explanation:Myelodysplastic syndromes are a group of clonal haematopoietic disorders which are characterised by anaemia, leukopenia and thrombocytopenia.
Patients will complain of fatigue, symptoms of thrombocytopenia such as nosebleeds and easy bleeding and a history of repeated infections due to low white blood cells (especially Neutrophils).
In Chronic lymphocytic leukaemia production of hematopoietic cells goes on for a longer time.
Folate and B12 deficiency would result in hypersegmented neutrophils and a raised MCV.
Iron deficiency anaemia would not cause neutropenia or thrombocytopenia.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 17
Incorrect
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A 40-year-old man with episodes of blood in urine and flank pain that are recurrent presents for management. He has a history of hypertension that is difficult to control and recurrent urinary tract infections. Other findings are: bilateral masses in his flanks and haematuria (3+ on dipstick).
What is the most likely diagnosis?Your Answer: Alport syndrome
Correct Answer: Polycystic kidney disease
Explanation:Autosomal dominant polycystic kidney disease (ADPKD) presents with abdominal or loin discomfort due to the increasing size of the kidneys, acute loin pain with or without haematuria, hypertension, and male infertility. It is the most common cause of serious renal disease and the most common inherited cause of renal failure in adults.
Alport syndrome has hearing loss and eye abnormalities in addition to symptoms of kidney disease.
Renal cell carcinoma presents with additional features of unexplained weight loss, loss of appetite, fever of unknown origin and anaemia.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 18
Incorrect
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Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer: IgM
Correct Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).
IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.
IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 19
Incorrect
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Question 20
Incorrect
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Regarding conduction of nerve impulses, which of the following statements is CORRECT:
Your Answer: The action potential in an unmyelinated nerve has an amplitude that declines with distance from its site of origin.
Correct Answer: The action potential in myelinated axons is propagated only at the nodes of Ranvier.
Explanation:An action potential is a self-propagating response, successive depolarisation moving along each segment of an unmyelinated nerve until it reaches the end. It is all-or-nothing and does not decrease in size. Conduction in myelinated fibres is much faster, up to 50 times that of the fastest unmyelinated nerve. Myelinated fibres are insulated except at areas devoid of myelin called nodes of Ranvier. The depolarisation jumps from one node of Ranvier to another by a process called saltatory conduction. Saltatory conduction not only increases the velocity of impulse transmission but also conserves energy for the axon because depolarisation only occurs at the nodes and not along the whole length of the nerve fibre. Larger diameter myelinated nerve fibres conduct nerve impulses faster than small unmyelinated nerve fibres.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 21
Incorrect
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When a child has mumps, how long should he or she be off from school?
Your Answer: 4 days from onset of rash
Correct Answer: 5 days from onset of swelling
Explanation:To avoid the spread of infection, infected patients should be isolated. Patients should avoid going to school, childcare, or job for five days after the swelling has occurred.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 22
Incorrect
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A 65-year-old man comes for a visit at the clinic with complaints of abdominal pain. On inquiring about drug history, you find out that he has been taking around 8-10 paracetamol to help relieve the pain.
Out of the following, which one is believed to be the main mechanism of action for paracetamol?Your Answer: Selective inhibition of COX-2 receptors
Correct Answer: Selective inhibition of COX-3 receptors
Explanation:The FDA categorizes Paracetamol as an NSAID (nonsteroidal anti-inflammatory drug) as it is believed to selectively inhibit cyclo-oxygenase 3 (COX-3) receptors in the brain and spinal cord.
COX-3 is a unique variant of the more known COX-1 and COX-2. It is responsible for the production of prostaglandins in central areas, which sensitizes free nerve endings to the chemical mediators of pain. Therefore, by selectively inhibiting COX-3, paracetamol effectively reduces pain sensation by increasing the pain threshold.
Acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, therefore, has no peripheral anti-inflammatory effects.
The antipyretic actions of acetaminophen are likely attributed to direct action on heat-regulating centres in the brain, resulting in peripheral vasodilation, sweating, and loss of body heat. -
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 23
Incorrect
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Question 24
Correct
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A man presents to the emergency department with a hand laceration that has damaged the opponens digiti minimi muscle.
All of the following statements regarding the opponens digiti minimi muscle is considered correct, except:Your Answer: It is innervated by the superficial branch of the ulnar nerve
Explanation:Opponens digiti minimi (ODM) is an intrinsic muscle of the hand. It’s a triangular muscle that extends between the hamate bone (carpal bone) and the 5th metacarpal bone. It forms the hypothenar muscle group together with the abductor digiti minimi and flexor digiti minimi brevis, based on the medial side of the palm (hypothenar eminence). These muscles act together in moving the little finger. The opponens digiti minimi is responsible for flexion, lateral rotation and opposition of the little finger.
Its origin is the hook of hamate and flexor retinaculum. It inserts into the medial border of 5th metacarpal bone. It is innervated by the deep branch of the ulnar nerve, which stems from the brachial plexus (C8, T1 spinal nerves).
Its blood supply is by the deep palmar branch of ulnar artery and deep palmar arch, which is the terminal branch of the radial artery. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 25
Incorrect
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A 22-year-old woman comes in with an asthmatic flare. Salbutamol is her only regular medication.
What is the dosage per inhalation of a standard metered dose salbutamol inhaler?Your Answer: 100 milligrams
Correct Answer: 100 micrograms
Explanation:The dose of a conventional metered dose inhaler is 100 micrograms per metered inhalation.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 26
Incorrect
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Which of the following classes of drugs may predispose to lithium toxicity:
Your Answer: Theophylline
Correct Answer: Thiazide diuretics
Explanation:Excretion of lithium may be reduced by thiazide diuretics, NSAIDs, and ACE inhibitors thus predisposing to lithium toxicity. Loop diuretics also cause lithium retention but are less likely to result in lithium toxicity.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 27
Incorrect
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Regarding bronchiolitis, which of the following statements is CORRECT:
Your Answer: It occurs most commonly from infection with parainfluenza virus.
Correct Answer: Chest x-ray may show hyperinflation and increased peribronchial markings.
Explanation:Acute bronchiolitis is caused most commonly by respiratory syncytial virus, occurring mostly in children aged 6 months to 2 years. Children with bronchiolitis are febrile and tachypnoeic with a dry cough and difficulty feeding. Examination may reveal chest hyperinflation, respiratory distress, wheezing and fine end-inspiratory crepitations. Chest x-ray may show hyperinflation and increased peribronchial markings (although CXR should only performed if there is diagnostic uncertainty or an atypical course). Treatment is usually supportive, aerosolized ribavirin is reserved for severely ill or immunocompromised patients.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 28
Incorrect
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A 55-year-old female is urgently rushed into the Emergency Department as she complains of chest pain that is worse on breathing, shortness of breath, palpitations, and haemoptysis.
She undergoes a CT pulmonary angiogram, which reveals a large pulmonary embolus. She is immediately started on heparin and shifted to the acute medical ward.
Which of the following statements is true regarding heparin?Your Answer: It is more effective than its low-molecular-weight derivates in preventing mortality from thrombosis
Correct Answer: It activates antithrombin III
Explanation:Heparin is a polymer of glycosaminoglycan. It occurs naturally and is found in mast cells. Clinically, it is used in two forms:
1. Unfractionated: widely varying polymer chain lengths
2. Low molecular weight: Smaller polymers onlyHeparin works by binding to and activating the enzyme inhibitor antithrombin III. Antithrombin III inactivates thrombin (factor IIa) by forming a 1:1 complex with thrombin. The heparin-antithrombin III complex also inhibits factor Xa and some other proteases involved with clotting. The heparin-ATIII complex can also inactivate IX, XI, XII, and plasmin.
Heparin is not thrombolytic or fibrinolytic. It prevents the progression of existing clots by inhibiting further clotting. The lysis of existing clots relies on endogenous thrombolytics.
Heparin is used for:
1. Prevention and treatment of venous thromboembolism
2. Treatment of disseminated intravascular coagulation
3. Treatment of fat embolism
4. Priming of haemodialysis and cardiopulmonary bypass machinesThere is no evidence that heparin is superior to low-molecular-weight heparins in preventing mortality from thrombosis.
Vitamin K is used to reverse the effects of warfarin but not heparin. For heparin, protamine sulphate is used to counteract its effects.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 29
Incorrect
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Which of the following statements is correct regarding the partial pressure of oxygen during respiration?
Your Answer: Alveolar PO 2 > Inhaled PO 2
Correct Answer: Exhaled PO 2 > Alveolar PO 2
Explanation:Because of humidification, inspired PO2 in the airways is less than inhaled PO2.
Because of gas exchange, alveolar PO2 is less than inhaled or inspired PO2.
Because of mixing with anatomical dead space (air that has not taken part in gas exchange, exhaled PO2 is greater than alveolar O2, and therefore that has relatively higher PO2 on the way out, but is less than inhaled or inspired PO2.
Typical values for a resting young healthy male (in kPa) are shown below:
-Inhaled air: PO221.2, PCO20.0
-Inspired air in airways (after humidification): PO219.9, PCO20.0
-Alveolar air (after equilibrium with pulmonary capillaries): PO213.3, PCO25.3
-Exhaled air (after mixing with anatomical dead space air): PO215.5, PCO24.3 -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 30
Correct
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A 63-year-old man complains of chest pain and syncope on occasion. His heart rate is 37 beats per minute, and he has a second-degree heart block, according to his rhythm strip.
Which of the following would be the most appropriate next step in his management, according to the ALS bradycardia algorithm?Your Answer: Give atropine 500 mcg
Explanation:Atropine 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 atropine 500 mcg IV:
Shock
Syncope
Myocardial ischemia
Insufficiency of the heartIf this does not work, give additional 500 mcg doses at 3-5 minute intervals until a maximum dose of 3 mg is reached. The heart rate can be slowed paradoxically if the dose is higher than 3 mg.
The ALS bradycardia algorithm also suggests the following interim measures:
Transcutaneous pacing
Isoprenaline infusion 5 mcg/min
Adrenaline infusion 2-10 mcg/minutes
Alternative drugs (aminophylline, dopamine, glucagon, glycopyrrolate) -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
