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Question 1
Incorrect
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A 65-year-old man complains of headaches, weakness, cramps, and confusion; blood tests reveal he has severe hyponatremia. The most likely cause is:
Your Answer: Low haematocrit
Correct Answer: Severe diarrhoea or vomiting
Explanation:Hyponatraemia occurs when the sodium level in the plasma falls below 135 mmol/l. Hyponatraemia is an abnormality that can occur in isolation or, more commonly as a complication of other medical illnesses. Severe hyponatraemia may cause osmotic shift of water from the plasma into the brain cells. Typical symptoms include nausea, vomiting, headache and malaise. As the hyponatraemia worsens, confusion, diminished reflexes, convulsions, stupor or coma may occur. The cause of hyponatremia is typically classified by a person’s fluid status into low volume, normal volume, and high volume. Low volume hyponatremia can occur from diarrhoea, vomiting, diuretics, and sweating.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 2
Incorrect
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A 77-year-old woman's renal function is tested. The following results were obtained during a 24-h period: Urine flow rate: 2. 0 ml/min, Urine inulin: 0.5 mg/ml, Plasma inulin: 0.02 mg/ml, Urine urea: 220 mmol/l, Plasma urea: 5 mmol/l. What is the urea clearance?
Your Answer:
Correct Answer: 88 ml/min
Explanation:Urea is reabsorbed in the inner medullary collecting ducts of the nephrons. The clearance (C) of any substance can be calculated as follows: C = (U × V)/P, where U and P are the urine and plasma concentrations of the substance, respectively and V is the urine flow rate. So, glomerular filtration rate = (0.220 × 2. 0)/0.005 = 88 ml/min.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 3
Incorrect
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A 67 year old man brought to the emergency department with acute pancreatitis is immediately intubated and put on a ventilator. His intra-abdominal pressure is measured using a bladder catheter connected to manometry. Which of the following would most likely represent the pressure effect seen in abdominal compartment syndrome?
Your Answer:
Correct Answer: Bladder pressure of 16–25 mmHg does not require decompression
Explanation:Bladder pressures below 5mm Hg are expected in healthy patients. Pressures between 10 to 15 mmHg can be expected following abdominal surgery and in obese patients. Bladder pressures over 25 mmHg are highly suspicious of abdominal compartment syndrome and should be correlated clinically. It is recommended that pressure measurements be trended to show and recognize the worsening of intra-abdominal hypertension. Recommended management at this stage includes fluid resuscitation and if the pressure rises beyond the critical threshold of 25 mmHg, abdominal decompression is required.
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This question is part of the following fields:
- Emergency Medicine And Management Of Trauma
- Principles Of Surgery-in-General
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Question 4
Incorrect
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A 65 year old man has colorectal cancer Duke C. What is his 5 year prognosis?
Your Answer:
Correct Answer: 50%
Explanation:Dukes staging and 5 year survival:
Dukes A – Tumour confined to the bowel but not extending beyond it, without nodal metastasis (95%)
Dukes B – Tumour invading bowel wall, but without nodal metastasis (75%)
Dukes C – Lymph node metastases (50%)
Dukes D – Distant metastases (6%) -
This question is part of the following fields:
- Oncology
- Principles Of Surgery-in-General
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Question 5
Incorrect
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Which of the following two cerebral veins join up to form the great cerebral vein, otherwise also known as the great vein of Galen?
Your Answer:
Correct Answer: Internal cerebral veins
Explanation:The great vein of Galen or great cerebral vein, is formed by the union of the internal cerebral veins and the basal veins of Rosenthal. This vein curves upwards and backwards along the border of the splenium of the corpus callosum and eventually drains into the inferior sagittal sinus and straight sinus at its anterior extremity.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 6
Incorrect
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A 46 year old politician with chronic hepatitis for several years visits the clinic for a review. Recently, his AFP is noted to be increased and an abdominal ultrasound demonstrates a 2.2cm lesion in segment V of the liver. What is the most appropriate course of action?
Your Answer:
Correct Answer: Liver MRI
Explanation:In patients with liver tumours, it is crucial to detect and stage the tumours at an early stage (to select patients who will benefit from curative liver resection, and avoid unnecessary surgery). Therefore, an optimal preoperative evaluation of the liver is necessary, and a contrast-enhanced MRI is widely considered the state-of-the-art method. Liver MRI without contrast administration is appropriate for cholelithiasis but not sufficient for most liver tumour diagnoses.
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This question is part of the following fields:
- Generic Surgical Topics
- Hepatobiliary And Pancreatic Surgery
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Question 7
Incorrect
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Elevated mean corpuscular volume with hypersegmented neutrophils and low reticulocyte index is seen in on the blood count of a middle-aged lady about to undergo elective surgery. On enquiry, she mentions feeling tired for a few months. Which of the following investigations should be carried out in her to reach a diagnosis?
Your Answer:
Correct Answer: Serum vitamin B12 and folate
Explanation:Elevated levels of MCV indicates megaloblastic anaemia, which are associated with hypersegmented neutrophils. Likely causes include vitamin B12 or folate deficiency. Megaloblastic anaemia results from defective synthesis of DNA. As RNA production continues, the cells enlarge with a large nucleus. The cytoplasmic maturity becomes greater than nuclear maturity. Megaloblasts are produced initially in the marrow, before blood. Dyspoiesis makes erythropoiesis ineffective, causing direct hyperbilirubinemia and hyperuricemia. As all cell lines are affected, reticulocytopenia, thrombocytopenia and leukopenia develop. Large, oval blood cells (macro-ovalocytes) are released in the circulation, along with presence of hypersegmented neutrophils.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 8
Incorrect
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A patient in the recovery ward after cardiac surgery is noticed to have a small effusion in the lowest extent of the pleural cavity, into which no lung tissue extends. What is the name of this part of the pleural cavity?
Your Answer:
Correct Answer: Costodiaphragmatic recess
Explanation:The costodiaphragmatic recess is the part of the pleural cavity where the costal pleura is in continuity with the diaphragmatic pleura. It forms the lowest extent of the pleural cavity.
Costomediastinal recess: a tiny recess that is anteriorly located, where the costal pleura becomes continuous with the mediastinal pleura.
The cupola is the pleural cavity that extends above the first rib.
The inferior mediastinum refers to the posterior, middle and anterior mediastinal divisions together.
The pulmonary ligament on the other hand, is a pleural fold that is situated beneath the root of the lung on the medial aspect of the lung.
Oblique pericardial sinus is not part of the pleural cavity. -
This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 9
Incorrect
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A 34-year-old woman with severe burns, presented to casualty with a blood pressure of 75/40 mmHg and pulse of 172/minute. Obviously the patient is in shock. Which type of shock is it more likely to be?
Your Answer:
Correct Answer: Hypovolaemic shock
Explanation:Shock is a life-threatening condition that occurs when the organs and tissues of the body are not receiving a sufficient flow of blood. Lack of blood flow, oxygen and nutrients results in the inability to function properly and damage to many organs. Shock requires immediate treatment because, if left untreated the impaired tissue perfusion and cellular hypoxia can cause irreversible tissue injury, collapse, coma or even death. There are various types of physiological shock, including: cardiogenic (due to heart damage), hypovolaemic (due to low total volume of blood or plasma), neurogenic (due to nervous system damage), septic (due to infections) and anaphylactic shock (due to allergic reactions). Hypovolaemic shock can be caused by blood loss due to trauma, internal bleeding or other fluid loss due to severe burns, prolonged diarrhoea, vomiting and sweating.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 10
Incorrect
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A 4 week old baby is taken to the clinic with bile stained vomiting. He had a congenital diaphragmatic hernia and an exomphalos. What is the most likely underlying condition?
Your Answer:
Correct Answer: Intestinal malrotation
Explanation:Answer: Intestinal malrotation
During normal abdominal development, the 3 divisions of the GI tract (i.e., foregut, midgut, hindgut) herniate out from the abdominal cavity, where they then undergo a 270º counter clockwise rotation around the superior mesenteric vessels. Following this rotation, the bowels return to the abdominal cavity, with fixation of the duodenojejunal loop to the left of the midline and the cecum in the right lower quadrant.
Intestinal malrotation refers to any variation in this rotation and fixation of the GI tract during development. Interruption of typical intestinal rotation and fixation during foetal development can occur at a wide range of locations; this leads to various acute and chronic presentations of disease. The most common type found in paediatric patients is incomplete rotation predisposing to midgut volvulus, requiring emergent operative intervention.
Acute midgut volvulus
Usually occurs during the first year of life
Sudden onset of bilious emesis
Diffuse abdominal pain out of proportion to physical examination
Acute duodenal obstruction
This anomaly is usually recognized in infants and is due to compression or kinking of the duodenum by peritoneal bands (Ladd bands).
Patients present with forceful vomiting, which may or may not be bile-stained, depending on the location of the obstruction with respect to the entrance of the common bile duct (ampulla of Vater).
Malrotation may occur as an isolated anomaly or in association with other congenital anomalies; 30-62% of children with malrotation have an associated congenital anomaly. All children with diaphragmatic hernia, gastroschisis, and omphalocele have intestinal malrotation by definition. Additionally, malrotation is seen in approximately 17% of patients with duodenal atresia and 33% of patients with jejunoileal atresia.
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This question is part of the following fields:
- Generic Surgical Topics
- Paediatric Surgery
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Question 11
Incorrect
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Injury to which of the following arteries is likely to affect the blood supply to the seminal vesicles?
Your Answer:
Correct Answer: Middle rectal
Explanation:Ligation of middle rectal artery is most likely to affect the blood supply of seminal vesicles since arteries supplying the seminal vesicles are derived from the middle and inferior vesical and middle rectal arteries.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 12
Incorrect
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A 41 year old woman presents with discomfort in her left breast. On examination, she has a discrete, soft, fluctuant area in the upper outer quadrant of her left breast. A halo sign is observed on the mammogram. What is the most likely explanation for this process?
Your Answer:
Correct Answer: Breast cyst
Explanation:A breast cyst is a fluid-filled sac within the breast. They are often described as round or oval lumps with distinct edges. In texture, a breast cyst usually feels like a soft grape or a water-filled balloon, but can also feel firm.
Breast cysts can be painful and may be worrisome but are generally benign. They are most common in pre-menopausal women in their 30s or 40s. They usually disappear after menopause, but may persist or reappear when using hormone therapy. They are also common in adolescents. Breast cysts can be part of fibrocystic disease. The pain and swelling is usually worse in the second half of the menstrual cycle or during pregnancy.
The halo sign, described as a complete or partial radiolucent ring surrounding the periphery of a breast mass, has long been considered a mammographic sign indicating a benign process. The phenomenon is most frequently seen with cysts and fibroadenomas.
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This question is part of the following fields:
- Breast And Endocrine Surgery
- Generic Surgical Topics
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Question 13
Incorrect
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An X ray of a 60 year old male brought to the accident and emergency following a fall down stairs shows a fractured olecranon process of the right ulna with the line of fracture passing through the superior surface, disrupting a muscle. Which among the following muscles was most likely injured?
Your Answer:
Correct Answer: Triceps brachii
Explanation:The superior surface of the olecranon process forms an attachment for the insertion of the triceps brachii on the posterior aspect. It also has a minor transverse groove for the attachment of part of the posterior ligament of the elbow on the anterior aspect.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 14
Incorrect
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Some substances, such as Chromium-51 and Technetium-99, are freely filtered but not secreted or absorbed by the kidney. In these cases, their clearance rate is equal to:
Your Answer:
Correct Answer: Glomerular filtration rate
Explanation:If a substance passes through the glomerular membrane with perfect ease, the glomerular filtrate contains virtually the same concentration of the substance as does the plasma and if the substance is neither secreted nor reabsorbed by the tubules, all of the filtered substance continues on into the urine. Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 15
Incorrect
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An old woman complains of a lack of sensation halfway down the anterior surface of the thigh. The cause of this:
Your Answer:
Correct Answer: Would result from damage to the nerve that innervates the pectineus muscle
Explanation:The pectineus is supplied by the second, third and fourth lumbar nerves through the femoral nerve and by the third lumbar through the accessory obturator when it exists. The anterior surface of the thigh receives its innervation from the femoral nerve as well, thus this is the nerve most likely to be injured
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 16
Incorrect
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A 30-year-old male presents with a lump in his scalp. It is located approximately 4cm superior to the external occipital protuberance. It feels smooth and slightly fluctuant and has a centrally located small epithelial defect. What is the most likely underlying diagnosis?
Your Answer:
Correct Answer: Sebaceous cyst
Explanation:Epidermoid cysts represent the most common cutaneous cysts. While they may occur anywhere on the body, they occur most frequently on the face, scalp, neck, and trunk.
Because most lesions originate from the follicular infundibulum, the more general term epidermoid cyst is favoured. The term sebaceous cyst should be avoided because it implies that the cyst is of sebaceous origin.
Epidermoid cysts are usually asymptomatic. Discharge of a foul-smelling “cheese like” material may be described. Less frequently, the cysts can become inflamed or infected, resulting in pain and tenderness. In the uncommon event of malignancy, rapid growth, friability, and bleeding may be reported.
Epidermoid cysts appear as flesh–coloured-to-yellowish, firm, round nodules of variable size. A central pore or punctum may be present.
Certain hereditary syndromes are associated with epidermoid cysts. Such syndromes include Gardner syndrome, basal cell nevus syndrome, and pachyonychia congenita. In addition, idiopathic scrotal calcinosis may actually represent an end-stage of dystrophic calcification of epidermoid cysts.
Epidermoid cysts may be removed via simple excision or incision with removal of the cyst and cyst wall through the surgical defect. If the entire cyst wall is not removed, the lesion may recur. Excision with punch biopsy technique may be used if the size of the lesion permits. Minimal-incision surgery, with reduced scarring, has been reported. An intraoral approach has been used to minimize facial scarring.
Incision and drainage may be performed if a cyst is inflamed. Injection of triamcinolone into the tissue surrounding the inflamed cyst results in a faster improvement in symptoms. This may facilitate the clearing of infection; however, it does not eradicate the cyst. -
This question is part of the following fields:
- Generic Surgical Topics
- Skin Lesions
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Question 17
Incorrect
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Which of the following clinical signs will be demonstrated in a case of Brown-Séquard syndrome due to hemisection of the spinal cord at mid-thoracic level?
Your Answer:
Correct Answer: Ipsilateral spastic paralysis, ipsilateral loss of vibration and proprioception (position sense) and contralateral loss of pain and temperature sensation beginning one or two segments below the lesion
Explanation:Brown–Séquard syndrome results due to lateral hemisection of the spinal cord and results in a loss of motricity (paralysis and ataxia) and sensation. The hemisection of the cord results in a lesion of each of the three main neural systems: the principal upper motor neurone pathway of the corticospinal tract, one or both dorsal columns and the spinothalamic tract. As a result of the injury to these three main brain pathways the patient will present with three lesions. The corticospinal lesion produces spastic paralysis on the same side of the body (the loss of moderation by the upper motor neurons). The lesion to fasciculus gracilis or fasciculus cuneatus results in ipsilateral loss of vibration and proprioception (position sense). The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion. At the lesion site, all sensory modalities are lost on the same side, and an ipsilateral flaccid paralysis.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 18
Incorrect
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Regarding the extensor retinaculum of the wrist, which of these is CORRECT?
Your Answer:
Correct Answer: It prevents the tendons of the posterior compartment of the forearm from ‘bowstringing’ when the hand is extended at the wrist
Explanation:This extensor retinaculum, as the name indicates, holds the tendons of the extensors against the dorsal surface of the distal radius and ulna. Therefore, the correct answer is that it prevents bowstringing of the extensor tendons with wrist extension. It forms compartments between it and its bony attachment, and these compartments guide and hold the tendons.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 19
Incorrect
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A 41-year-old man presents with a severe left-sided loin pain radiating to the groin. Imaging demonstrates a 2 mm left-sided calculus in the distal ureter. Renal function is normal. What should be the most appropriate course of action?
Your Answer:
Correct Answer: Arrange to review the patient in two weeks with a KUB X-ray
Explanation:As the stone is smaller in size, there is a strong likelihood (75%) of it to be passed spontaneously. Furthermore, distally sited stones are more likely to pass spontaneously than proximally sited ones. Hence, it should be arranged to review the patient in two weeks with a KUB X-ray.
Urolithiasis affects up to 15% of the population worldwide. The development of sudden-onset, colicky loin to groin pain is a classical feature in the history. It is nearly always associated with haematuria that is either micro- or macroscopic. The most sensitive and specific diagnostic test is helical, non-contrast CT scanning.
Management options for urolithiasis are:
1. Most renal stones measuring <5mm in maximum diameter typically pass within four weeks of onset of symptoms. More intensive and urgent treatment is indicated in the presence of ureteric obstruction, renal developmental abnormality such as horseshoe kidney, and previous renal transplant.
2. Ureteric obstruction due to stones together with infection is a surgical emergency and the system must be decompressed. Options include nephrostomy tube placement, insertion of ureteric catheters, and ureteric stent placement.
3. In the non-emergency setting, the preferred options for treatment include extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, ureteroscopy, and open surgery (selected cases). Minimally invasive options are the most popular first-line treatment. -
This question is part of the following fields:
- Generic Surgical Topics
- Urology
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Question 20
Incorrect
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Signals pass through neuromuscular junctions via the neurotransmitter acetylcholine. After release from the skeletal neuromuscular junction, acetylcholine:
Your Answer:
Correct Answer: Causes postsynaptic depolarisation
Explanation:Acetylcholine is released from the presynaptic membrane into the cleft where it binds to the ion gated channels on the post synaptic membrane, causing them to open. This results in sodium entering into the fibre and further depolarizing it, creating an action potential.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
