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Question 1
Correct
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Which of these conditions is mithramycin used for?
Your Answer: Hypercalcaemia of malignancy
Explanation:Mithramycin or Plicamycin is a tricyclic pentaglycosidic antibiotic derived from Streptomyces strains. It inhibits RNA and protein synthesis by adhering to DNA. It is used as a fluorescent dye and as an antineoplastic agent. It is also used to reduce hypercalcaemia, especially caused by malignancy. Plicamycin is currently used in multiple areas of research, including cancer cell apoptosis and as a metastasis inhibitor.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 2
Correct
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Action potentials are used extensively by the nervous system to communicate between neurones and muscles or glands. What happens during the activation of a nerve cell membrane?
Your Answer: Sodium ions flow inward
Explanation:During the generation of an action potential, the membrane gets depolarized which cause the voltage gated sodium channels to open and sodium diffuses inside the neuron, resulting in the membrane potential moving towards a positive value. This positive potential will then open the voltage gated potassium channels and cause more K+ to move out decreasing the membrane potential and restoring the membrane potential to its resting value.
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This question is part of the following fields:
- General
- Physiology
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Question 3
Correct
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A 15-day old baby was brought to the emergency department with constipation for 4 days. On examination, the abdomen of the baby was found to be distended and tender all over. No bowel sounds were heard. A sigmoid colon biopsy was carried out, which showed absent ganglion cells. What is the diagnosis?
Your Answer: Hirschsprung’s disease
Explanation:Hirschsprung’s disease is characterized by congenital absence of the autonomic plexus (Meissner’s and Auerbach’s plexus) in the intestinal wall. Usually limited to the distal colon, it can occasionally involve the entire colon or even the small bowel. There is abnormal or absent peristalsis in the affected segment, resulting in continuous spasm of smooth muscle and partial/complete obstruction. This causes accumulation of intestinal contents and dilatation of proximal segment. Skip lesions are highly uncommon. This disease is seen early in life with 15% patients presenting in first month, 60% by 1 year of age and 85% by the age of 4 years. Symptoms include severe and complete constipation, abdominal distension and vomiting. Patients with involvement of ultra-short segments might have mild constipation with intervening diarrhoea. In older children, symptoms include failure to thrive, anorexia, and lack of an urge to defecate. On examination, an empty rectum is revealed with stool palpable high up in the colon. If not diagnosed in time, it can lead to Hirschsprung’s enterocolitis (toxic megacolon), which can be fulminant and lead to death. Diagnosis involves a barium enema or a rectal suction biopsy. Barium enema shows a transition in diameter between the dilated, normal colon proximal to the narrowed, affected distal segment. It is to be noted that barium enema should be done without prior preparation, which can dilate the abnormal segment, leading to a false-negative result. A 24-hour post-evacuation film can be obtained in the neonatal period – if the colon is still filled with barium, there is a high likelihood of Hirschsprung’s disease. Full-thickness rectal biopsy is diagnostic by showing the absence of ganglion cells. Acetylcholinesterase staining can be done to highlight the enlarged nerve trunks. Abnormal innervation can also be demonstrated by rectal manometry.
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This question is part of the following fields:
- Gastrointestinal; Hepatobiliary
- Pathology
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Question 4
Correct
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A 33-year old lady presented to the gynaecology clinic with amenorrhoea for 6 months and a recent-onset of milk discharge from her breasts. She was not pregnant or on any medication. On enquiry, she admitted to having frequent headaches the last 4 months. Which of the following findings would you expect to see in her condition?
Your Answer: Hyperprolactinaemia
Explanation:Excessively high levels of prolactin in the blood is called hyperprolactinaemia. Normally, prolactin levels are less than 580 mIU/l in females and less than 450 mIU/l in men. The biologically inactive macroprolactin can lead to a false high reading. However, the patient remains asymptomatic. Dopamine down-regulates prolactin whereas oestrogen upregulates it. Hyperprolactinaemia can be caused due to lack of inhibition (compression of pituitary stalk or low dopamine levels), or increased production due to a pituitary adenoma (prolactinoma). Either of these causes can lead to a prolactin level of 1000-5000 mIU/l. However, levels more than 5000mIU/l are usually associated due to an adenoma and >100,000 mIU/l are seen in macroadenomas (tumours < 1cm in diameter). Increased prolactin causes increased dopamine release from the arcuate nucleus of hypothalamus. This increased dopamine in turn, inhibits the GnRH (Gonadotrophin Releasing Hormone) thus blocking gonadal steroidogenesis resulting in the symptoms of hyperprolactinaemia. In women, it includes hypoestrogenism, anovulatory infertility, decreased or irregular menstruation or complete amenorrhoea. It can even cause production of breast milk, loss of libido, vaginal dryness and osteoporosis. In men, the symptoms include impotence, decreased libido, erectile dysfunction and infertility. In men, treatment can be delayed due to late diagnosis as they have no reliable indicator such as menstruation that might indicate a problem. Most of the male patients seek help only when headaches and visual defects start to surface.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 5
Correct
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What is the role of ICAM-1 and VCAM-1 in the inflammatory process?
Your Answer: Leukocyte adhesion
Explanation:Steps involved in leukocyte arrival and function include:
1. margination: cells migrate from the centre to the periphery of the vessel.
2. rolling: selectins are upregulated on the vessel walls.
3. adhesion: upregulation of the adhesion molecules ICAM and VCAM on the endothelium interact with integrins on the leukocytes. Interaction of these results in adhesion.
4. diapedesis and chemotaxis: diapedesis is the transmigration of the leukocyte across the endothelium of the capillary and towards a chemotactic product.
5. phagocytosis: engulfing the offending substance/cell.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 6
Correct
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The wound healing process is documented in patients undergoing laparoscopic procedures. The port incisions are sutured closed and the wounds observed every few weeks for re-epithelialisation and tensile strength. Which substance is mostly likely to be found at a cellular level involved in wound healing?
Your Answer: Tyrosine kinase
Explanation:Cell surface growth factor receptors require intercellular proteins such as tyrosine kinase which are necessary to initiate a series of events that eventually lead to cell division and growth. Tyrosine kinase is an enzyme that transfers a phosphate group to the tyrosine residue in a protein. This phosphorylation will lead to an up regulation of the enzyme activity.
Fibronectin acts in the extracellular matrix to bind macromolecules (such as proteoglycans) via integrin receptors to aid attachment and migration of cells.
Laminin is an extracellular matrix component that is abundant in basement membranes.
Hyaluronic acid is one of the proteoglycans in the extracellular matrix.
Collagen fibres are part of the extracellular matrix that gives strength and stability to connective tissues.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 7
Correct
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An operation to resect a tumour of the right lung was stopped as the chest surgeon said that the tumour was crossing the oblique fissure. Which structures are separated by the oblique fissure of the right lung?
Your Answer: Lower lobe from both upper and middle lobes
Explanation:The oblique fissure on the right lung separates the lower lobe from both the middle and upper lobe. The lingual is only found on the left lung and is part of the upper lobe.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 8
Correct
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The third branch of the maxillary artery lies in which fossa?
Your Answer: Pterygopalatine fossa
Explanation:The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. It is divided into three portions:
– The first or mandibular portion (or bony portion) passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament.
– The second or pterygoid portion (or muscular portion) runs obliquely forward and upward under cover of the ramus of the mandible, on the surface of the lateral pterygoid muscle; it then passes between the two heads of origin of this muscle and enters the fossa.
– The third portion lies in the pterygopalatine fossa in relation to the pterygopalatine ganglion. This is considered the terminal branch of the maxillary artery. Branches from the third portion includes: the sphenopalatine artery, descending palatine artery, infraorbital artery, posterior superior alveolar artery, artery of pterygoid canal, pharyngeal artery, middle superior alveolar artery and anterior superior alveolar artery.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 9
Correct
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Which of the following substances will enhance the activity of antithrombin III?
Your Answer: Heparin
Explanation:Antithrombin III is a glycoprotein that inactivates multiple enzymes involved in the coagulation system. It inactivates factor X, factor IX, factor II, factor VII, factor XI and factor XII. Its activity is greatly increased by the action of heparin.
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This question is part of the following fields:
- General
- Physiology
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Question 10
Correct
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A 72 year old man suffered a MI. What is the approximate time needed by the scar tissue of the MI to recover and attain full strength?
Your Answer: Several months
Explanation:A week following a MI attack, a little collagen starts to form and deposit. By the end of the 2nd week, neovascularisation of the scar occurs, with some collagen being laid down in a haphazard fashion. By this time the scar attains some strength. During the next 6 months, collagen is constantly being laid down and is rearranged in order to shrink the scar. Most of the blood vessels by this time have regenerated, decreasing vascularity of the scar reaching full maturity.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Cardiovascular
- Pathology
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Question 11
Correct
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A 7-year-old boy with facial oedema was brought to the hospital by his parents. Renal function is normal and urinalysis revealed the presence of a profound proteinuria. Which of the following is the most probable cause of these findings?
Your Answer: Minimal-change disease
Explanation:Minimal-change disease (MCD) refers to a histopathologic glomerular lesion, typically found in children, that is almost always associated with nephrotic syndrome. The most noticeable symptom of MCD is oedema, which can develop very rapidly. Due to the renal loss of proteins muscle wasting and growth failure may be seen in children. Renal function is usually not affected and a proteinuria of more than 40 mg/h/m2 is the only abnormal finding in urinalysis.
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This question is part of the following fields:
- Pathology
- Renal
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Question 12
Correct
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A 41 year old women presents with a history of carcinoma involving the right breast with enlarged axillary nodes on the same side. She underwent mastectomy and axillary node clearance. These were sent for histopathological examination. They showed no signs of metastasis. What could be cause of this enlargement in the lymph nodes?
Your Answer: Sinus histiocytosis
Explanation:Sinus histiocytosis also referred to as reticular hyperplasia, refers to the enlargement, distention and prominence of the sinusoids of the lymph nodes. This is a non-specific form of hyperplasia characteristically seen in lymph nodes that drain tumours. The endothelial lining of the lymph node becomes markedly hypertrophied, along with an increase in the number of macrophages which results in the distortion, distention and enlargement of the sinus. In this scenario there is no evidence that an infection or another malignancy could account for the enlargement. Paracortical lymphoid hyperplasia is caused by an immune response.
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This question is part of the following fields:
- Inflammation & Immunology; Female Health
- Pathology
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Question 13
Correct
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The anatomical dead space in a patient with low oxygen saturation, is 125 ml, with a tidal volume of 500 ml and pa(CO2) of 40 mm Hg. The dead space was determined by Fowler's method. If we assume that the patient's lungs are healthy, what will his mixed expired CO2 tension [pE(CO2)] be?
Your Answer: 30 mmHg
Explanation:According to Bohr’s equation, VD/VT = (pA(CO2) − pE(CO2))/pA(CO2), where pE(CO2) is mixed expired CO2 and pA(CO2) is alveolar CO2pressure. Normally, the pa(CO2) is virtually identical to pA(CO2). Thus, VD/VT = (pa(CO2)) − pE(CO2)/pa(CO2). By Fowler’s method, VD/VT= 0.25. In the given problem, (pa(CO2) − pE(CO2)/pa(CO2) = (40 − pE(CO2)/40 = 0.25. Thus, pE(CO2) = 30 mmHg. If there is a great perfusion/ventilation inequality, pE(CO2) could be significantly lower than 30 mm Hg, and the patient’s physiological dead space would exceed the anatomical dead space.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 14
Correct
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An electronic manufacturing engineer had abdominal distension and underwent a CT scan of the abdomen. Thereafter he was diagnosed with hepatic angiosarcoma. Exposure to what agent is responsible for the development of this neoplasm?
Your Answer: Arsenic
Explanation:Hepatic angiosarcomas are associated with particular carcinogens which includes: arsenic , thorotrast, and polyvinyl chloride. With exposure to this three agents, there is a very long latent period of many years between exposure and the development of tumours.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 15
Correct
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A 53 year old women with a history of atrial fibrillation developed an acute abdomen. On laparoscopic examination her bowels appeared to be dusky to red-purple in colour and her mesenteric veins appeared to be patent. Which of the following is most likely to occur in this situation?
Your Answer: Wet gangrene
Explanation:Infarction of the small bowel following a sudden and complete occlusion of the mesenteric artery can involve any portion of the bowel, whether small or a large. The splenic flexure is at most risk for infarction as it is the watershed area between the superior and inferior mesenteric vessels. Regardless of whether the arterial or the venous blood vessels are occluded, because of the blood reflow into the damaged portion, it will appear haemorrhagic. The bowel appearing congested at first and then becoming oedematous. If the artery is occluded then there will be a clear cut demarcation and in venous occlusion the dusky colour fades with the rest of the normal bowel. Wet gangrene is characteristic of ischaemic injury to the gut.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Gastrointestinal
- Pathology
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Question 16
Correct
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Question 17
Correct
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A new-born was found to have an undeveloped spiral septum in the heart. This is characteristic of which of the following?
Your Answer: Persistent truncus arteriosus
Explanation:Persistent truncus arteriosus is a congenital heart disease that occurs when the primitive truncus does not divide into the pulmonary artery and aorta, resulting in a single arterial trunk. The spiral septum is created by fusion of a truncal septum and the aorticopulmonary spiral septum. Incomplete development of these septa results in incomplete separation of the common tube of the truncus arteriosus and the aorticopulmonary trunk.
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This question is part of the following fields:
- Cardiovascular
- Pathology
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Question 18
Correct
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An organ transplant patient may be at risk of developing which type of cancer?
Your Answer: Skin cancer
Explanation:The most common malignancies encountered in the post–solid organ transplant setting are non-melanoma skin cancers, post-transplant lymphoproliferative disorders and Kaposi’s sarcoma (KS). The pathogenesis of these tumours is likely related to the immunosuppressive drugs used post-transplantation and subsequent viral infection.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 19
Correct
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A 45-year old gentleman presented to the emergency department at 5.00 AM with pain in his left flank. The pain began suddenly and presented in waves throughout the night. Urine examination was normal except for presence of blood and few white blood cells. The pH and specific gravity of the urine were also found to be within normal range. What is the likely diagnosis?
Your Answer: Ureteric calculus
Explanation:A calculus in the ureter, if less than 5mm in diameter is likely to pass spontaneously. However, a larger calculus irritates the ureter and may become lodged, leading to hydroureter and/or hydronephrosis. Likely sites where the calculus might get lodged, include pelviureteric junction, distal ureter at the level of iliac vessels and the vesicoureteric junction. An obstruction can result in reduced glomerular filtration. There can be deterioration in renal function due to hydronephrosis and a raised glomerular pressure, leading to poor renal blood flow. Permanent renal dysfunction usually takes about 4 weeks to occur. Secondary infection can also occur in chronic obstruction.
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This question is part of the following fields:
- Pathology
- Renal
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Question 20
Correct
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A 49-year-old woman with acute renal failure has a total plasma [Ca2+] = 2. 5 mmol/l and a glomerular filtration rate of 160 l/day. What is the estimated daily filtered load of calcium?
Your Answer: 240 mmol/day
Explanation:Calcium is the most abundant mineral in the human body. The average adult body contains in total approximately 1 kg of calcium of which 99% is in the skeleton in the form of calcium phosphate salts. The extracellular fluid (ECF) contains approximately 22 mmol, of which about 9 mmol is in the plasma. About 40% of total plasma Ca2+ is bound to proteins and not filtered at the glomerular basement membrane. Therefore, the estimated daily filtered load is 1.5 mmol/l × 160 l/day = 240 mmol/day. The exact amount of free versus total Ca2+ depends on the blood pH: free Ca2+ increases during acidosis and decreases during alkalosis.
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This question is part of the following fields:
- Physiology
- Renal
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Question 21
Correct
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A construction worker is brought to the A&E after a fall on site. The patient is conscious but complains of inability to feel his legs. A neurological examination reveals that he has no cutaneous sensation from his umbilicus to his toes. What is the likely level of the spinal cord that is injured?
Your Answer: T10
Explanation:The umbilicus has a relatively consistent position in humans and thus serves as an important land mark. The skin around the waist at the level of the umbilicus is supplied by the tenth thoracic spinal nerve (T10 dermatome).
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 22
Correct
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A 28-year old lady comes to the surgical clinic with a recently detected lump in her right breast. On examination, the lump is found to be 1cm, rubbery, mobile with no palpable axillary nodes. Mammography reveals no microcalcifications and the opposite breast appears normal. What is the likely diagnosis?
Your Answer: Fibroadenoma
Explanation:A benign breast tumour, fibroadenoma is common below the age of 30 years and occurs due to oestrogenic excess. It is characterised by proliferation of both glandular and stromal elements. Fibroadenomas are usually solitary and are mobile, not fixed to surrounding structures. The tumour is elastic, nodular and encapsulated with a grey-white cut surface. The two main histological types include intracanalicular and pericanalicular types, with both types often present in the same tumour. In the intracanalicular type, the stromal proliferation component predominates causing compression of ducts making them appear slit-like. In pericanalicular type, the fibrous stroma dominates around the ductal spaces so that they remain oval on cross section.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 23
Correct
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Which of these infectious agents tends to affect people under 20 and over 40 years old, can cause acute encephalitis with cerebral oedema and petechial haemorrhages, along with haemorrhagic lesions of the temporal lobe. A lumbar puncture will reveal clear cerebrospinal fluid with an elevated lymphocyte count?
Your Answer: Herpes simplex virus
Explanation:Haemorrhagic lesions of the temporal lobe are typical of Herpes simplex encephalitis (HSE). It tends to affect patients aged under 20 or over 40 years, and is often fatal if left untreated. In acute encephalitis, cerebral oedema and petechial haemorrhages occur and direct viral invasion of the brain usually damages neurones. The majority of cases of herpes encephalitis are caused by herpes simplex virus-1 (HSV-1), and about 10% of cases of herpes encephalitis are due to HSV-2, which is typically spread through sexual contact.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 24
Correct
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A 55 year old lady underwent an uneventful appendicectomy. Two hours later, her arterial blood gas analysis on room revealed pH: 7.30, p(CO2): 53 mmHg and p(O2): 79 mmHg. What is the most likely cause of these findings?
Your Answer: Alveolar hypoventilation
Explanation:In the given problem, there is respiratory acidosis due to hypercapnia from a low respiratory rate and/or volume (hypoventilation). Causes of hypoventilation include conditions impairing the central nervous system (CNS) respiratory drive, impaired neuromuscular transmission and other causes of muscular weakness (drugs and sedatives), along with obstructive, restrictive and parenchymal pulmonary disorders. Hypoventilation leads to hypoxia and hypercapnia reduces the arterial pH. Severe acidosis leads to pulmonary arteriolar vasoconstriction, systemic vascular dilatation, reduced myocardial contractility, hyperkalaemia, hypotension and cardiac irritability resulting in arrhythmias. Raised carbon dioxide concentration also causes cerebral vasodilatation and raised intracranial pressure. Over time, buffering and renal compensation occurs. However, this might not be seen in acute scenarios where the rise in p(CO2) occurs rapidly.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 25
Correct
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The extent of cancer growth can be described through staging. What is taken into consideration when staging a cancer?
Your Answer: Local invasion
Explanation:Cancer stage is based on four characteristics: the size of cancer, whether the cancer is invasive or non-invasive, whether the cancer has spread to the lymph nodes, and whether the cancer has spread to other parts of the body, in this case beyond the breast. Staging is important as it is often a good predictor of outcomes and treatment is adjusted accordingly.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 26
Correct
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Which Statement is true of the brachial plexus?
Your Answer: The posterior cord continues as the axillary nerve
Explanation:The lateral cord continues as the musculocutaeous nerve.
The medial cord continues as the ulnar nerve.
The posterior cord continues as the radial nerve and the axillary nerve.
The nerve to subclavius muscle is a branch of the C6 root.
The suprascapular nerve is a branch from the upper trunk.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 27
Correct
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The vascular structure found on the right side of the fifth lumbar vertebra is?
Your Answer: Inferior vena cava
Explanation:The most likely vascular structure is the inferior vena cava. The inferior vena cava is formed by the joining of the two common iliac arteries, the right and the left iliac artery, at the level of the fifth lumbar vertebra( L5). The inferior vena cava passes along the right side of the vertebral column. It enters the thoracic cavity into the underside of the heart through the caval opening of the diaphragm at the level of the eight thoracic vertebra (T8).
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 28
Correct
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A space defined by the teres major muscle, the teres minor muscle, long head of the triceps brachii muscle and surgical neck of the humerus contains the axillary nerve and the?
Your Answer: Posterior circumflex humeral artery
Explanation:This quadrangular space transmits the posterior circumflex humeral vessels and the axillary nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 29
Correct
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The vagus nerve passes through which of the following foramen?
Your Answer: Jugular foramen
Explanation:The jugular foramen is a large foramen in the base of the skull. It is located behind the carotid canal and is formed in front by the petrous portion of the temporal bone, and behind by the occipital bone. Cranial nerves IX, X, and XI and the internal jugular vein pass through the jugular foramen.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 30
Correct
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A 7-month-old abandoned baby with congenital non-communicating hydrocephalus is hosted by a clinic at its new-born hostel. A CT scan of the baby's brain reveals what might be a blockage of the ventricular system between the third and the fourth ventricles. Which of the following is the most likely blocked structure?
Your Answer: Cerebral aqueduct
Explanation:The drainage of cerebral spinal fluid from the third ventricle to the fourth ventricle is carried out by the cerebral aqueduct. The cerebral aqueduct is the narrowest passageway in the entire ventricular system and thus forms the most common site of blockage of flow of cerebrospinal fluid. The interventricular foramen allows passage of CSF to the third ventricle. The foramen of Luschka and Magendie are located on the fourth ventricle and allow passage of CSF to the subarachnoid space from the ventricular system. The pontine cistern is a space located on the ventral aspect of the pons. The cisterna magna is an opening on the subarachnoid space between the pia matter and the arachnoid.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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SESSION STATS - PERFORMANCE PER SPECIALTY
