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Question 1
Correct
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A 23-year-old has a known diagnosis of HIV. Blood is sent to the laboratory for tests.
AIDS be diagnosed at a CD4 counts below?Your Answer: 200 cells/mm 3
Explanation:A normal CD4 count ranges from 500-1000 cells/mm3.
At CD4 count of less than 350 cells/mm3 treatment with anti-retroviral therapy should be considered.
At a CD4 count of >200 cells/mm3 AIDS is diagnosed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 2
Correct
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The pathophysiology of Addison's disease is as follows:
Your Answer: Adrenocortical insufficiency
Explanation:Primary adrenal insufficiency, also known as Addison’s disease, occurs when the adrenal glands cannot produce an adequate amount of hormones despite a normal or increased corticotropin (ACTH) level.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 3
Correct
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You've been summoned to a young man in the resus area who is experiencing an SVT. You decide to use adenosine after trying several vagal manoeuvres without success.
Which of the following is the correct adenosine mechanism of action?Your Answer: Opens K + channels in the heart
Explanation:The purine nucleoside adenosine is used to diagnose and treat paroxysmal supraventricular tachycardia. Adenosine works by stimulating A1-adenosine receptors and opening potassium channels that are sensitive to acetylcholine. This causes the atrioventricular (AV) node’s cell membrane to become hyperpolarized, slowing conduction by inhibiting calcium channels.
Patients who have had a heart transplant are extremely sensitive to the effects of adenosine and should start with a lower dose of 3 mg, then 6 mg, and finally 12 mg.Dipyridamole potentiates the effects of adenosine, so it should be used with caution in patients who are taking it.
The use of adenosine is contraindicated in the following situations:
Asthma
COPD (chronic obstructive pulmonary disease)
Decompensated heart failureÂ
Long QT syndrome
AV block in the second or third degree
Sinusitis is a condition in which the sinuses become (unless pacemaker fitted)
Hypotension that is severe -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 4
Correct
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Which of the following is required for vitamin B12 absorption:
Your Answer: Intrinsic factor
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 5
Correct
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A young male has presented to the Emergency Department with a sudden onset of severe palpitations, shortness of breath, and chest pain. A 12-lead ECG is recorded, and it shows a narrow complex tachycardia that points to a diagnosis of supraventricular tachycardia.
Vagal manoeuvres are attempted but are unsuccessful in eliminating the arrhythmia. The next action plan is to use a drug to revert to sinus rhythm.
Out of the following, which is the first-line treatment for supraventricular tachycardia?Your Answer: Adenosine
Explanation:Paroxysmal supraventricular tachycardia is an intermittent tachycardia (HR > 100 bpm) and has the following characteristics:
1. Sudden onset/offset (Contrast with sinus tachycardia)
2. Electrical activity originates above the ventricle (Contrast with ventricular tachycardia)
3. Produces narrow QRS complex (<120ms) The most common cause of PSVT is Atrioventricular nodal re-entrant tachycardia (AVNRT), most common in young women with a mean age onset of 32 years old. There are recurrent episodes of palpitations, and most of the episodes spontaneously. Sometimes, some vagal manoeuvres are required:
1. Valsalva manoeuvre
2. immersing the face in ice-cold water
3. carotid sinus massage.If PSVT keeps persisting or is causing severe symptoms, the treatment of choice is intravenous adenosine. The patient’s ECG should be continuously monitored throughout the treatment.
The recommended doses in adults are as follows:
– Initial dose of adenosine is 6 mg by rapid IV bolus
– If unsuccessful, give another dose of adenosine 12 mg by rapid IV bolus
– If unsuccessful, give a further dose of adenosine 12 mg by rapid IV bolus
The latest ALS guidelines advocate 18 mg for the third dose, whereas the BNF/NICE guidelines advocate 12 mg.If adenosine fails or is contraindicated, intravenous verapamil can be used as an alternative, but it should be avoided in patients recently treated with beta-blockers.
Synchronized electrical cardioversion will be necessary with signs of hemodynamic instability or if drug treatment has failed to restore sinus rhythm.
Recurrent episodes of paroxysmal supraventricular tachycardia can be treated by catheter ablation or prevented with drugs such as flecainide, sotalol, diltiazem, or verapamil. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 6
Correct
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A 10-year-old girl that appears systemically well presents with a honey-crusted scab close to the corner of her mouth and states that the area is slightly itchy but not painful. The diagnosis given was impetigo.
What is most likely the mode of transmission of the causative agent of the said diagnosis?Your Answer: Direct contact
Explanation:Impetigo is a common pyoderma that is most often seen in children. Historically, most cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years.
A bullous form of impetigo accounts for approximately 10% of cases. It is caused by strains of S. aureus that produce exfoliative toxins leading to the formation of bullae, which quickly rupture and form a transparent, light brown crust.
Impetigo is spread mainly by person-to-person contact; it is rapidly spread through direct transmission. The diagnosis of impetigo can be made from a Gram stain and culture of the vesicular contents.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 7
Correct
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C-reactive protein (CRP) synthesis is predominantly stimulated by which of the following cytokines:
Your Answer: IL-6
Explanation:Activated leukocytes, adipocytes, and endothelial cells all release interleukin 6 (IL-6), a significant proinflammatory cytokine. The main downstream mediator of the acute phase response is C-reactive protein, which is predominantly produced by IL-6–dependent hepatic biosynthesis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 8
Correct
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A 43-year old male is taken to the Emergency Room for a lacerated wound on the abdomen, situated above the umbilicus. A short segment of the small bowel has herniated through the wound.
Which of these anatomic structures is the deepest structure injured in the case above?Your Answer: Transversalis fascia
Explanation:The following structures are the layers of the anterior abdominal wall from the most superficial to the deepest layer:
Skin
Fatty layer of the superficial fascia (Camper’s fascia)
Membranous layer of the superficial fascia (Scarpa’s fascia)
Aponeurosis of the external and internal oblique muscles
Rectus abdominis muscle
Aponeurosis of the internal oblique and transversus abdominis
Fascia transversalis
Extraperitoneal fat
Parietal peritoneum -
This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 9
Correct
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Which of the following body location is the appropriate site to apply pressure when performing a carotid sinus massage?
Your Answer: Thyroid cartilage
Explanation:The common carotid artery runs through the neck and divides into internal and external carotid arteries on both sides near the upper thyroid cartilage. In emergency situations, carotid sinus massage is also used to diagnose or treat paroxysmal supraventricular tachycardia.
During the procedure, to maximize access to the carotid artery, the patient is put in a supine position with the neck extended (i.e. elevating the chin away from the chest). The carotid sinus is normally positioned inferior to the angle of the jaw, near the arterial impulse, at the level of the thyroid cartilage. For 5 to 10 seconds, pressure is administered to one carotid sinus.
Although pulsatile pressure applied in a vigorous circular motion may be more effective, continuous pressure is preferred since it is more reproducible. If the predicted reaction is not obtained, the operation is repeated on the opposite side after a one- to two-minute wait.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 10
Correct
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Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: Germination and outgrowth of clostridial spores depends on anaerobic conditions.
Explanation:Clostridium tetani is found in normal human intestinal flora, although infection is predominantly exogenous. Tetanospasmin, an exotoxin produced by C. tetani is responsible for the neurotoxic effects of tetanus, largely by preventing the release of the inhibitory neurotransmitter GABA, resulting in prolonged excitation. Clostridium tetani is an obligate anaerobe, with an incubation period of about 3 – 21 days (average 10 days).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 11
Correct
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Regarding gastric motility and emptying, which of the following statements is CORRECT:
Your Answer: Gastric emptying is inhibited by the presence of the products of fat digestion in the duodenum.
Explanation:Gastric emptying is decreased by the presence of fats in the duodenum (by stimulating release of cholecystokinin). Mixing of the food with gastric secretions takes place in the distal body and antrum of the stomach where the muscularis externa layer is thicker. The stomach has an additional inner oblique smooth muscle layer (in addition to the inner circular layer and outer longitudinal layer). Gastric emptying is increased by a low gastric pH and decreased by a low duodenal pH.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 12
Correct
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Which of the following infections is vancomycin most likely prescribed for?
Your Answer: Clostridium difficile colitis
Explanation:125 mg PO q6hr for 10 days is indicated for treatment of Clostridium difficile (C. difficile)-associated diarrhoea
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 13
Correct
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What is the approximate lifespan of the mature erythrocyte:
Your Answer: 120 days
Explanation:Erythrocytes have a normal lifespan of about 120 days. Mature erythrocytes are biconcave discs with no nucleus, ribosomes or mitochondria but with the ability to generate energy as ATP by the anaerobic glycolytic pathway. The red cell membrane consists of a bipolar lipid layer with a membrane skeleton of penetrating and integral proteins anchoring carbohydrate surface antigens. The shape and flexibility of red cells allows them to deform easily and pass through capillaries.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 14
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 15
Correct
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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 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 16
Correct
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A patient with a history of worsening chronic breathlessness on exertion undergoes lung function testing. The results demonstrate an FEV 1 that is 58% predicted and an FEV 1 /FVC ratio less than 0.7.
Which of the following is the most likely diagnosis? Select ONE answer only.Your Answer: COPD
Explanation:Obstructive lung disorders are characterised by airway obstruction. Many obstructive diseases of the lung result from narrowing of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself.
In obstructive lung disease, FEV1is reduced to <80% of normal and FVC is usually reduced but to a lesser extent than FEV1. The FEV1/FVC ratio is reduced to <0.7.
Types of obstructive lung disorders include:
Chronic obstructive pulmonary disease (COPD)
Asthma
Bronchiectasis -
This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 17
Correct
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Regarding tapeworm, which of the following statements is CORRECT:
Your Answer: Diagnosis is by direct visualisation of characteristic eggs in the stool.
Explanation:Diagnosis of tapeworm is by direct visualisation of characteristic eggs in stool. Humans may be infected by pork or beef tapeworm. Treatment is with praziquantel or niclosamide. Specialist advice should be sought for the management of neurocysticercosis.Iron-deficiency anaemia is typically seen in hookworm infection. Threadworms migrate from the intestine at night to lay eggs on the perianal skin. Mebendazole is first line treatment for threadworms.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 18
Correct
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Most of the lymph from vessels that drain the breast is collected in which of the following lymph nodes?
Your Answer: Axillary nodes
Explanation:Lymph is the fluid that flows through the lymphatic system.
Axillary lymph nodes are near the breasts. They are often the first location to which breast cancer spreads if it moves beyond the breast tissue. They receive approximately 75% of lymph drainage from the breast via lymphatic vessels, laterally and superiorly.
The lymph usually first drains to the anterior axillary nodes, and from here, through the central axillary, apical, and supraclavicular nodes in sequence.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 19
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 20
Incorrect
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Which of the following decreases activation of vitamin D:
Your Answer: Hypophosphataemia
Correct Answer: Chronic renal failure
Explanation:Calcium deficiency (low Ca2+ diet or hypocalcemia) activates 1-alpha-hydroxylase in the cells of the renal proximal tubule which catalyses the conversion of vitamin D to its active form, 1,25-dihydroxycholecalciferol. Increased parathyroid hormone (PTH) and hypophosphatemia also stimulate the enzyme. Chronic renal failure is associated with a constellation of bone diseases, including osteomalacia caused by failure of the diseased renal tissue to produce the active form of vitamin D.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 21
Correct
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At the start of the cardiac cycle, towards the end of diastole, all of the following statements are true EXCEPTÂ for:
Your Answer: The semilunar valves are open.
Explanation:At the start of the cardiac cycle, towards the end of diastole, the whole of the heart is relaxed. The atrioventricular (AV) valves are open because the atrial pressure is still slightly greater than the ventricular pressure. The semilunar valves are closed, as the pressure in the pulmonary artery and aorta is greater than the ventricular pressures. The cycle starts when the sinoatrial node (SAN) initiates atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 22
Incorrect
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Which of the following is the most potent stimulus of fibrinolysis:
Your Answer: Antithrombin
Correct Answer: Tissue plasminogen activator
Explanation:Fibrinolysis is a normal haemostatic response to vascular injury. Plasminogen, a proenzyme in blood and tissue fluid, is converted to plasmin by activators either from the vessel wall (intrinsic activation) or from the tissues (extrinsic activation). The most important route follows the release of tissue plasminogen activator (TPA) from endothelial cells.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 23
Correct
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A tumour compresses the jugular foramen of a 50-year-old patient. Compression of several nerves in the jugular foramen will result in which of the following complications?
Your Answer: Loss of gag reflex
Explanation:The glossopharyngeal nerve, which is responsible for the afferent pathway of the gag reflex, the vagus nerve, which is responsible for the efferent pathway of the gag reflex, and the spinal accessory nerve all exit the skull through the jugular foramen. These nerves are most frequently affected if the jugular foramen is compressed. As a result, the patient’s gag reflex is impaired.
The vestibulocochlear nerve is primarily responsible for hearing. The trigeminal nerve provides sensation in the face. The facial nerve innervates the muscles of face expression (including those responsible for closing the eye). Tongue motions are controlled mostly by the hypoglossal nerve.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 24
Correct
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An 82 year old man has fever, left sided abdominal and back pain and presents to the emergency room. Imaging reveals a large perinephric abscess. Which of the following most likely describes the fluid location:
Your Answer: Between the renal capsule and the renal fascia
Explanation:The perinephric fat is immediately external to the renal capsule and completely surrounds the kidney. The renal fascia surrounds the perinephric fat and the paranephric fat is external to the renal fascia. The location of a perinephric abscess is in the perinephric fat between the renal capsule and the renal fascia.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 25
Correct
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What is the primary mode of action of Enoxaparin?
Your Answer: Inhibits factor Xa
Explanation:Heparin acts as an anticoagulant by enhancing the inhibition rate of clotting proteases by antithrombin III impairing normal haemostasis and inhibition of factor Xa. Low molecular weight heparins have a small effect on the activated partial thromboplastin time and strongly inhibit factor Xa. Enoxaparin is derived from porcine heparin that undergoes benzylation followed by alkaline depolymerization.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 26
Correct
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An 11-year-old girl presents with a 5-day history of persistent fever despite regular paracetamol, throbbing left ear pain, ear discharge and deafness. Her parents have observed that she is not her usual self, not eating well, and has been lethargic. On examination there is a tender swelling in the post auricular region on the left hand side.
What is the most likely causative organism?
Your Answer: Streptococcus pneumonia
Explanation:Acute mastoiditis is a complication (rare) of acute otitis media (AOM) and the commonest causative organism is Streptococcus pneumoniae.
Generally, acute mastoiditis presents with:
Pyrexia
Recent history of AOM
Mastoid swelling and erythema
Otalgia
Otorrhoea and perforation of tympanic membrane
Post-auricular pain
Protrusion of the ears -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 27
Correct
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A patient with diplopia is found to have eye deviation downwards and outwards. The likely nerves that are affected are:
Your Answer: Oculomotor nerve
Explanation:The results of an oculomotor (CN III) nerve palsy are a depressed and abducted (down and out) eye, ptosis, diplopia, and a fixed and dilated pupil.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 28
Correct
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A 66-year-old patient attends the Emergency Department with chest pain. His ECG and troponin are suggestive of a new myocardial infarction. You have explained the condition and the prognosis. He asks you about how the damaged area of his heart will heal following this.
Which answer best describes the process of myocardial healing following myocardial infarction? Select ONE answer only.Your Answer: The damaged myocardium will form non-contractile scar tissue
Explanation:Myocardial cells are unable to regenerate, they are unable to divide in response to tissue injury. The remain permanently in G0 and cannot progress to G1. If a segment of muscle dies, for example in myocardial infarction, this tissue will be replaced by scar tissue if the patient recovers. This scar tissue is non-contractile and therefore the remaining myocardium must work harder to maintain cardiac output. As a consequence the remaining undamaged myocardium undergoes compensatory hypertrophy without cell division.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 29
Correct
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Where on the body is the radial artery pulsation best palpated?
Your Answer: At the wrist just lateral to the flexor carpi radialis tendon
Explanation:The radial artery lies lateral to the large tendon of the flexor carpi radialis muscle and anterior to the pronator quadratus at the distal end of the radius. The flexor carpi radialis muscle is used as a landmark in locating the pulse.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 30
Incorrect
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A patient with a wound infection on his right leg has reddening and oedema of the surrounding muscles. His condition has worsened considerably over the past few hours with the area now appearing blackened. There is also palpable crepitus under the skin. You suspect gas gangrene.
Which statement about Clostridium perfringens is true?Your Answer:
Correct Answer: Gas gangrene is caused by the release of an alpha-toxin
Explanation:Clostridium perfringens, a Gram-positive, anaerobic, spore forming rod-shaped, pathogenic bacterium is the most commonly associated with gas gangrene (85-90% of cases), although other species can also be implicated.
Clostridium perfringens is capsulate and produces a range of toxins. Alpha-toxin is the most important and is the cause of gas gangrene.
Gas gangrene develops when a devitalized wound becomes infected with Clostridium perfringens spores from the environment. The spores germinate and multiplies in the ischaemic conditions, releasing toxins, which further damage tissues.
Usually, the clinical features of gas gangrene appear within 24 hours of injury.
Clostridium perfringens spores are not destroyed by cooking. During slow cooling and unrefrigerated storage, they germinate to form vegetative cells.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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SESSION STATS - PERFORMANCE PER SPECIALTY
