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Question 1
Incorrect
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Which of the following comprises a negative feedback mechanism?
Your Answer: Detectors, attenuators, comparators, a set point and effectors
Correct Answer: Detectors, comparators, a variable set point and effectors
Explanation:Negative feedback loops, also known as inhibitory loops, play a crucial role in controlling human health. It is a self-regulating mechanism of some sort.
A negative feedback system is made up of three main components: a detector (often neural receptor cells) that measures the variable in question and provides input to the comparator; a comparator (usually a neural assembly in the central nervous system) that receives input from the detector, compares the variable to the variable set point, and determines whether or not a response is required.
The comparator activates an effector (typically muscular or glandular tissue) to conduct the appropriate reaction to return the variable to its set point.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 2
Incorrect
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A 23-year-old student presents to the emergency department with a terrible headache, photophobia, and a fever. On her lower limbs, you see a non-blanching purpuric rash. In the department, a lumbar puncture is conducted. What do you think you'll notice on Gram stain:
Your Answer: Gram positive diplococci
Correct Answer: Gram negative diplococci
Explanation:Bacterial meningitis and septicaemia are most commonly caused by meningococcal bacteria. The Gram-negative diplococci Neisseria Meningitidis causes meningitis. Gram stain and culture of CSF identify the etiologic organism, N meningitidis. In bacterial meningitis, Gram stain is positive in 70-90% of untreated cases, and culture results are positive in as many as 80% of cases.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 3
Correct
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Regarding the resting membrane potential, which of the following statements is CORRECT:
Your Answer: The resting cell membrane is more permeable to K + ions than to Na + ions.
Explanation:A membrane potential is a property of all cell membranes, but the ability to generate an action potential is only a property of excitable tissues. The resting membrane is more permeable to K+and Cl-than to other ions (and relatively impermeable to Na+); therefore the resting membrane potential is primarily determined by the K+equilibrium potential. At rest the inside of the cell is negative relative to the outside. In most neurones the resting potential has a value of approximately -70 mV.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 4
Correct
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In patients who are not at risk of hypercapnic respiratory failure but are requiring oxygen, the oxygen saturations should be maintained at which of the following?
Your Answer: 94 - 98%
Explanation:Oxygen saturation should be 94 – 98% in most acutely ill patients with a normal or low arterial carbon dioxide (PaCO2). In some clinical situations, however, like cardiac arrest and carbon monoxide poisoning, it is more appropriate to aim for the highest possible oxygen saturation until the patient is stable.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 5
Incorrect
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CSF is reabsorbed from subarachnoid space via which of the following structures:
Your Answer: Choroid plexus
Correct Answer: Arachnoid granulations
Explanation:From the subarachnoid cisterns in the subarachnoid space, CSF is reabsorbed via arachnoid granulations which protrude into the dura mater, into the dural venous sinuses and from here back into the circulation.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 6
Correct
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Nitrous oxide is associated with which of the following adverse effects:
Your Answer: Megaloblastic anaemia
Explanation:Exposure to nitrous oxide for prolonged periods, either by continuous or by intermittent administration, may result in megaloblastic anaemia as a result of interference with the action of vitamin B12; neurological toxic effects can occur without preceding overt haematological changes. Depression of white cell formation may also occur.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 7
Correct
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Haemophilia B results from a deficiency in:
Your Answer: Factor IX
Explanation:Haemophilia B is a bleeding disorder caused by a deficiency of clotting factor IX. It is the second commonest form of haemophilia, and is rarer than haemophilia A. Haemophilia B tends to be similar to haemophilia A but less severe. The two disorders can only be distinguished by specific coagulation factor assays.
The incidence is one-fifth of that of haemophilia A. Laboratory findings demonstrate prolonged APTT, normal PT and low factor IX.
Haemophilia B inherited in an X-linked recessive fashion, affecting males born to carrier mothers.
There is also a variation called Leyden, in which factor IX levels are below 1% until puberty, when they rise, potentially reaching as high as 40-60% of normal. This is thought to be due to the effects of testosterone at puberty. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 8
Correct
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Which of the following is typically a cause of a normal anion gap metabolic acidosis:
Your Answer: Diarrhoea
Explanation:FUSEDCARS can be used to remember some of the causes of a normal anion gap acidosis:
Fistula (pancreaticoduodenal)
Ureteroenteric conduit
Saline administration
Endocrine (hyperparathyroidism)
Diarrhoea
Carbonic anhydrase inhibitors (e.g. acetazolamide)
Ammonium chloride
Renal tubular acidosis
Spironolactone -
This question is part of the following fields:
- Physiology
- Renal
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Question 9
Incorrect
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Which of the following statements about vitamin B12 absorption is TRUE:
Your Answer: Receptors for the vitamin B12/Intrinsic factor complex are found in the duodenum allowing uptake of vitamin B12.
Correct Answer: On ingestion, vitamin B12 is bound to R protein which protects it from digestion in the stomach.
Explanation:The substance intrinsic factor,
essential for absorption of vitamin B12 in the ileum, is
secreted by the parietal cells along with the secretion of
hydrochloric acid. When the acid-producing parietal
cells of the stomach are destroyed, which frequently
occurs in chronic gastritis, the person develops not only
achlorhydria (lack of stomach acid secretion) but often
also pernicious anaemia because of failure of maturation
of the red blood cells in the absence of vitamin B12 stimulation of the bone marrow. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 10
Incorrect
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You see a 63-year-old man with a history of melaena and epigastric discomfort. For a few months, he's been taking aspirin.
Which of the following statements about aspirin's mechanism of action is correct?Your Answer: It only inhibits COX-2 at doses of 75 mg daily
Correct Answer: It inhibits both COX-1 and COX-2 at medium to high doses (500-5000 mg per day)
Explanation:Aspirin inhibits cyclo-oxygenase irreversibly by covalently acetylating the cyclo-oxygenase active site in both COX-1 and COX-2. The production of prostaglandin and thromboxane is reduced as a result. As a result, platelet activation and aggregation are reduced. A single dose of aspirin has a half-life of 7-10 days, which is the time it takes for the bone marrow to produce new platelets.
Aspirin only inhibits COX-1, the enzyme that produces thromboxane A2, at low doses (75 mg per day), and thus has a primarily anti-thrombotic effect.
Aspirin inhibits both COX-1 and COX-2 at medium to high doses (500-5000 mg per day). COX-2 is involved in the production of prostaglandins, so it has an anti-inflammatory effect at these concentrations.
Aspirin, when used as an antipyretic for a viral illness in children, can cause Reye’s syndrome. Reye’s syndrome is a potentially fatal liver disease that causes encephalopathy and liver failure.
The inability of aspirin to reduce platelet production of thromboxane A2, and thus platelet activation and aggregation, is known as aspirin resistance. Although the exact frequency and mechanism of aspirin resistance are unknown, it is thought to affect about 1% of users. Women are more likely than men to experience this phenomenon.
According to new research, taking aspirin on a regular basis lowers the risk of colorectal cancer. It may also protect against cancers of the breast, bladder, prostate, and lungs.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 11
Incorrect
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Regarding transport across a membrane, which of the following statements is CORRECT:
Your Answer: Secondary active transport is the transport of a molecule using an ATPase pump.
Correct Answer: Ion channels may be voltage-gated or ligand-gated.
Explanation:Diffusion is the passive movement of ions across a cell membrane down their electrochemical or concentration gradient through ion channels. Ion channels can be voltage-gated (regulated according to the potential difference across the cell membrane) or ligand-gated (regulated by the presence of a specific signal molecule). Facilitated diffusion is the process of spontaneous passive transport of molecules or ions down their concentration gradient across a cell membrane via specific transmembrane transporter (carrier) proteins. The energy required for conformational changes in the transporter protein is provided by the concentration gradient rather than by metabolic activity. In secondary active transport there is no direct coupling of ATP but the initial Na+ electrochemical gradient that drives the secondary active transport is set up by a process that requires metabolic energy. Examples include the sodium/calcium exchanger, or the sodium/glucose symporter.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 12
Correct
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A 69-year-old woman with new-onset back pain was diagnosed with osteopenia, osteolytic lesions, and vertebral collapse after undergoing a radiographic examination. Her laboratory results revealed anaemia and hypercalcemia. These findings most likely indicate what condition?
Your Answer: Myeloma
Explanation:Bone pain, pathologic fractures, weakness, anaemia, infection, hypercalcemia, spinal cord compression, and renal failure are all signs and symptoms of multiple myeloma (MM). The patient’s condition matched the signs and symptoms of myeloma.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 13
Incorrect
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An 11-year-old presented to a GP with a history of headache, neck stiffness and photophobia. On examination, HR is 122, BP is 87/42, RR is 28, SaO 2 is 95%, temperature is 39.4 o C. There is a recent petechial rash on legs and arms. The GP administered a dose of antibiotics in the prehospital setting before transferring to the Emergency Department. Which of these would the GP have administered?
Your Answer: IM benzylpenicillin 600 mg
Correct Answer: IM benzylpenicillin 1.2 g
Explanation:General Practitioners are advised to give a single injection of benzylpenicillin by intravenous or intramuscular injection before transferring the patient urgently to the ED when bacterial meningitis is suspected.
The recommended doses are:
Infants under 1 year: 300 mg
Children ages 1 to 9 years: 600 mg
Children aged 10 years and over: 1.2g
Adults: 1.2g -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 14
Correct
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Captopril should not be used if you have any of the following conditions:
Your Answer: Renal artery stenosis
Explanation:Contraindications indications of Captopril include:
– Bilateral renal artery stenosis
– Hypersensitivity to ACE inhibitors
– Anuria
– History of ACEI-induced angioedema
– Hereditary or idiopathic angioedema
– Co-administration of Neprilysin inhibitors (e.g., sacubitril) with ACE inhibitors may increase angioedema risk; do not administer ACE inhibitors within 36 hours of switching to or from sacubitril/valsartan.
If ACE inhibitors are used, they should be initiated only under specialist supervision and renal function should be monitored regularly. ACE inhibitors should also be used with particular caution in patients who may have undiagnosed and clinically silent renovascular disease. This includes patients with peripheral vascular disease or those with severe generalised atherosclerosis. -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 15
Correct
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Regarding dermatophytes, which of the following statement is CORRECT:
Your Answer: Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings.
Explanation:Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings depending on the site of infection. The lesions of ringworm typically have a dark outer ring with a pale centre. Tinea capitis is ringworm affecting the head and scalp. Spread is via direct skin contact. Treatment is usually topical, oral antifungals are reserved for refractory infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 16
Correct
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Mannitol is primarily indicated for which of the following:
Your Answer: Cerebral oedema
Explanation:Mannitol is an osmotic diuretic that can be used to treat cerebral oedema and raised intraocular pressure. Mannitol is a low molecular weight compound and is, therefore, freely filtered at the glomerulus and is not reabsorbed. It, therefore, increases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect. It also does not cross the blood-brain-barrier (BBB).
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 17
Correct
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Which of the following is NOT a common side effect of diazepam:
Your Answer: Bradycardia
Explanation:Adverse effects include:
Drowsiness and lightheadedness
Confusion and ataxia (especially in the elderly), amnesia, muscle weakness
Headache, vertigo, tremor, dysarthria, hypotension, decreased libido, erectile dysfunction, gynaecomastia, urinary retention
Paradoxical effects such as talkativeness, excitement, irritability, aggression, anti-social behaviour, and suicidal ideation
Withdrawal symptoms, for example anxiety, depression, anorexia, impaired concentration, insomnia, abdominal cramps, palpitations, tremor, tinnitus and perceptual disturbances
Tolerance and dependence (people who use benzodiazepines longer term can develop tolerance and eventual dependence) -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 18
Incorrect
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You're examining a 58-year-old male who has cellulitis in his left leg. Because he is allergic to penicillin, you start him on erythromycin.
Which of the following statements about erythromycin is correct?Your Answer: It acts by binding to the 30S subunit of the bacterial ribosome
Correct Answer: It can be used to treat Legionnaire’s disease
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolide antibiotics. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and thereby protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered to the infection site as a result.
Erythromycin is an orally active antibiotic that can also be given intravenously. It is metabolized in the liver and eliminated in the bile and has a biological half-life of 1.5 hours.
It has a similar antibacterial spectrum to benzylpenicillin (i.e., a narrow spectrum, primarily against Gram-positive pathogens) and can be used as a penicillin substitute in people who are allergic to penicillin.
Erythromycin is unsuccessful in the treatment of meningitis because it does not penetrate the central nervous system well enough. It is efficient against a variety of unusual pathogens, unlike penicillin. -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 19
Incorrect
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All of the following statements are considered true regarding L'Abbe plots, except:
Your Answer: Data on the upper left side of the plot indicates that experimental treatment is better than the control
Correct Answer: Treatment group results are plotted on the horizontal axis
Explanation:A L’Abbé plot is a scatter plot with the risk in the control group on the x-axis and the risk in the experimental group on the y-axis. It can be used to evaluate heterogeneity in meta-analysis. Furthermore, this plot can aid to choose a summary measure (odds ratio, risk ratio, risk difference) that will result in more consistent results.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 20
Incorrect
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer: Gas exchange across the alveolar-capillary membrane occurs via diffusion from an area of low partial pressure to an area of high partial pressure.
Correct Answer: Transfer of oxygen is usually perfusion-limited.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs until equilibrium is reached, but random movement of particles continues to occur and this is known as dynamic equilibrium. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO), not by measuring total lung capacity. The rate of transfer of a gas may be diffusion or perfusion limited; carbon monoxide transfer is diffusion-limited, oxygen transfer is usually perfusion-limited.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 21
Correct
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Regarding hypertensive crises, which of the following statements is CORRECT:
Your Answer: In a hypertensive emergency, blood pressure should be reduced by 20 - 25% within 2 hours.
Explanation:A hypertensive emergency is defined as severe hypertension (blood pressure ≥ 180/110 mmHg) with acute damage to the target organs. Prompt treatment with intravenous antihypertensive therapy is generally required; over the first few minutes or within 2 hours, blood pressure should be reduced by 20 – 25%. Severe hypertension without acute target organ damage is defined as hypertensive urgency.; blood pressure should be reduced gradually over 24 – 48 hours with oral antihypertensive therapy. If blood pressure is reduced too quickly in the management of hypertensive crises, there is a risk of reduced organ perfusion leading to cerebral infarction, blindness, deterioration in renal function, and myocardial ischaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 22
Correct
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The sensory innervation of the oropharynx is provided by which of the following nerves:
Your Answer: Glossopharyngeal nerve
Explanation:Each subdivision of the pharynx has a different sensory innervation:the nasopharynx is innervated by the maxillary nervethe oropharynx is innervated by the glossopharyngeal nervethe laryngopharynx is innervated by the vagus nerve.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 23
Correct
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Adrenocorticotropic hormone release from the anterior pituitary is stimulated by which of the following:
Your Answer: Corticotropin-releasing hormone
Explanation:ACTH secretion is stimulated by corticotropin-releasing hormone (CRH) from the hypothalamus.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 24
Incorrect
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An elderly patient presents to ED following a fall after feeling light headed when standing up. You are reviewing his medication and note that he is taking a high dose of furosemide. Loop diuretics act primarily at which of the following sites in the nephron:
Your Answer: Thin ascending limb
Correct Answer: Thick ascending limb
Explanation:Loop diuretics inhibit the Na+/K+/2Cl- symporter on the luminal membrane in the thick ascending limb of the loop of Henle, thus preventing reabsorption of NaCl and water. These agents reduce reabsorption of Cl- and Na+ and increase Ca2+ excretion and loss of K+ and Mg2+.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 25
Correct
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A 22 year old professional athlete sustains an inversion injury to her left ankle during the 800m. Which of the following ligaments is most likely injured:
Your Answer: Anterior talofibular ligament
Explanation:Inversion injuries at the ankle in plantarflexion (such as when wearing high heels) are common, and typically result in damage to the lateral collateral ligament of the ankle, made up of the anterior talofibular, the calcaneofibular and the posterior talofibular ligaments. The anterior talofibular and the calcaneofibular ligaments are most commonly injured, and the posterior talofibular ligament rarely. The spring ligament supports the head of the talus, the deltoid ligament supports the medial aspect of the ankle joint, and the long and short plantar ligaments are involved in maintaining the lateral longitudinal arch of the foot.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 26
Incorrect
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Which of the following microbes attaches to host cells by its haemagglutinin antigen:
Your Answer: Haemophilus influenzae
Correct Answer: Influenza virus
Explanation:Hemagglutinin (HA) or Haemagglutinin (BE) is an antigenic glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to the cell that is being infected. The name hemagglutinin comes from the protein’s ability to cause red blood cells (erythrocytes) to clump together (agglutinate) in vitro.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 27
Correct
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Herpes simplex virus is transmitted most commonly through which of the following routes:
Your Answer: Direct contact spread
Explanation:Herpes simplex virus is the most common cause of infective encephalitis and has a predilection for the temporal lobes. Herpes simplex is transmitted through direct contact. It invades skin locally producing skin vesicles by its cytolytic activity.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 28
Correct
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A 30-year-old woman is transfused following a diagnosis of anaemia secondary to heavy vaginal bleeding. She complains of feeling hot and cold during transfusion of the second unit and her temperature is 38.5ºC. Prior to the transfusion, her temperature was 37ºC. She has no other symptoms.
Which of these transfusions reactions most likely occurred?Your Answer: Febrile transfusion reaction
Explanation:Febrile transfusion reactions presents with an unexpected temperature rise (≥ 38ºC or ≥ 1ºC above baseline, if baseline ≥ 37ºC) during or shortly after transfusion. It is usually an isolated finding and the fever is accompanied by chills and malaise occasionally.
Allergic reaction is commonly caused by foreign plasma proteins but may be due to anti-IgA. Allergic type reactions usually present with urticaria, pruritus, hives. Associations include laryngeal oedema or bronchospasm.
Acute haemolytic reaction aka immediate haemolytic transfusion reaction presents with fever, chills, pain at transfusion site, nausea, vomiting, dark urine and feeling of ‘impending doom’. Often, it occurs due to ABO incompatibility.
Transfusion-associated circulatory overload (TACO) presents as acute or worsening respiratory distress within 6 hours of transfusion of a large volume of blood. It is common in patients with diminished cardiac reserve or chronic anaemia. Elderly patients, infants and severely anaemic patients are particularly susceptible. Clinical features of TACO include: Acute respiratory distress, Tachycardia, Hypertension, Acute/worsening pulmonary oedema on chest X-ray. The BNP is usually raised to at least 1.5 times the pre-transfusion baseline.
Transfusion-related lung injury (TRALI) is a form of acute respiratory distress caused by the donor plasma containing antibodies against the patient’s leukocytes. It is defined as hypoxia and bilateral pulmonary oedema that occurs within 6 hours of a transfusion in the absence of other causes of acute lung injury. Clinical features include Breathlessness, cough, frothy sputum, hypertension or hypotension, hypoxia and fever. Chest X-ray shows multiple perihilar nodules with infiltration of the lower lung fields.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 29
Incorrect
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Regarding local anaesthetics, which of the following statements is INCORRECT:
Your Answer: Lidocaine has class Ib anti-arrhythmic properties.
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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Question 30
Incorrect
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A 65-year-old man presents with a red, hot, swollen great toe. A diagnosis of acute gout is made. His past medical history includes heart failure and type 2 diabetes mellitus.
Which of the following is the most appropriate medication to use in the treatment of his gout? Select ONE answer only.Your Answer:
Correct Answer: Colchicine
Explanation:In the absence of any contra-indications, high-dose NSAIDs are the first-line treatment for acute gout. Naproxen 750 mg as a stat dose followed by 250 mg TDS is a commonly used and effective regime.
Aspirin should not be used in gout as it reduces the urinary clearance of urate and interferes with the action of uricosuric agents. Naproxen, Diclofenac or Indomethacin are more appropriate choices.
Allopurinol is used prophylactically, preventing future attacks by reducing serum uric acid levels. It should not be started in the acute phase as it increases the severity and duration of symptoms.
Colchicine acts on the neutrophils, binding to tubulin to prevent neutrophil migration into the joint. It is as effective as NSAIDs in relieving acute attacks. It also has a role in prophylactic treatment if Allopurinol is not tolerated.
NSAIDs are contra-indicated in heart failure as they can cause fluid retention and congestive cardiac failure. Colchicine is the preferred treatment in patients with heart failure or those who are intolerant of NSAIDs. -
This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
