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Question 1
Correct
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A 39-year-old homosexual is admitted with diarrhoea of three-month duration. He is found to be HIV positive with a CD4 cell count <50/μL. Which of the following organisms is most likely to be responsible?
Your Answer: Cryptosporidium
Explanation:Based on the history and findings, the most likely causative organism is cryptosporidium. It can cause severe, chronic, and possibly fatal diarrhoea in immunocompromised patients.
In patients with HIV/AIDS, clinical manifestations of cryptosporidiosis vary with the degree of immune compromise. Those with CD4 cell counts above 180–200/μL may be asymptomatic or develop self-limiting diarrhoeal illness. However, patients with advanced AIDS (CD4 cell counts <50/μL) can have severe diarrhoea that can persist for several months, resulting in severe dehydration, weight loss and malnutrition, extended hospitalizations, and mortality. In addition, patients with advanced AIDS are at greater risk of developing extraintestinal infection, particularly of the biliary, pancreatic, and respiratory tracts.
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This question is part of the following fields:
- Clinical Microbiology
- Principles Of Surgery-in-General
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Question 2
Correct
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Following a bee sting, a women develops a 2cm red, raised, swollen lesion at the site of the sting . Which of the following findings is likely to be seen in this lesion?
Your Answer: Vasodilation
Explanation:Inflammation is the immediate response of the body towards infections or irritations. The cardinal signs of inflammation are 1. redness/rubor, 2. tumour/swelling, 3.dolar/pain, 4.calor/heat and organ dysfunction (function laesa). Inflammation has 2 components; vascular and cellular. Blood vessels dilate upstream of the inflamed area leading to the rubor and calor and constrict downstream, increasing pressure and causing fluid to leak out of the capillary, resulting in swelling. The cellular component includes infiltration by neutrophils. Leukocyte arrival and functions include; 1. margination: cells marginated 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 resulting in adhesion, 4. diapedesis and chemotaxis: diapedesis is the transmigration of the leukocyte across the endothelium of the capillary and towards a chemotactic product and 5. phagocytosis: engulfing the offending substance/cell.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 3
Correct
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A 36 year old opera singer is admitted for a right thyroid lobectomy. Post operatively, he is unable to sing high notes. Which muscle is likely to demonstrate impaired function?
Your Answer: Cricothyroid
Explanation:Thyroidectomy has been reported as the most frequent cause of external branch of superior laryngeal nerve (EBSLN) injury.
Diagnosis of EBSLN injury may be difficult because the symptoms are nonspecific in many cases. However, advanced diagnostic techniques have revealed the incidence to be relatively high, ranging from 5 to 28%. Paralysis of the EBSLN causes difficulty with high pitch phonation and decreased pitch range secondary to failure of cricothyroid muscle stimulation and lack of tension in the vocal cord. This symptom may be extremely serious for professional voice users. EBSLN injury can also cause vocal fatigue, hoarseness, breathy sounding voice, and vocal nodules. -
This question is part of the following fields:
- Generic Surgical Topics
- Head And Neck Surgery
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Question 4
Correct
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A 36-year-old female was advised to undergo genetic testing of BRCA1 and BRCA2. BRCA1 and BRCA2 are tumour markers specifically for which organ?
Your Answer: Breast
Explanation:Women with harmful mutations in either BRCA1 or BRCA2 have a risk of breast cancer that is about five times the normal risk.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 5
Incorrect
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A medical student is told a substance is freely filtered but is not metabolised, secreted, or stored in the kidney. It has a plasma concentration of 1000 mg/l and its urine excretion rate is 25 mg/min, and the inulin clearance is 100 ml/min. What is the rate of tubular reabsorption of the substance?
Your Answer: 25 mg/min
Correct Answer: 75 mg/min
Explanation:Reabsorption or tubular reabsorption is the process by which the nephron removes water and solutes from the tubular fluid (pre-urine) and returns them to the circulating blood. To calculate the reabsorption rate of substance Z we use the following equation: excretion = (filtration + secretion) – reabsorption. As this substance is freely filtered, its filtration rate is equal to that of inulin. So 25 = (100 + 0) – reabsorption. Reabsorption = 100 – 25 therefore reabsorption = 75 mg/min.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 6
Incorrect
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A 40 year old male presents with jaundice and is diagnosed as having a carcinoma of the head of the pancreas. Despite being deeply jaundiced, his staging investigations are negative for metastatic disease. What is the best method of biliary decompression in this case?
Your Answer: Choledochoduodenostomy
Correct Answer: ERCP and placement of stent
Explanation:ERCP is a highly sensitive means of detecting pancreatic and/or biliary ductal abnormalities in pancreatic carcinoma. Among patients with pancreatic adenocarcinoma, 90-95% have abnormalities on ERCP findings.
ERCP is more invasive than the other diagnostic imaging modalities available for pancreatic carcinoma. ERCP also carries a 5-10% risk of significant complications. Because of this morbidity, it is usually reserved as a therapeutic procedure for biliary obstruction or for the diagnosis of unusual pancreatic neoplasms, such as intraductal pancreatic mucinous neoplasms (IPMN).
ERCP findings provide only limited staging information, but ERCP does have the advantage of allowing for therapeutic palliation of obstructive jaundice with either a plastic or metal biliary stent. -
This question is part of the following fields:
- Generic Surgical Topics
- Hepatobiliary And Pancreatic Surgery
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Question 7
Correct
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The thyroid gland is a large ductless gland located in which part of the neck?
Your Answer: Visceral space
Explanation:The thyroid gland is an endocrine gland in the neck, consisting of two lobes connected by an isthmus. It is situated at the front and sides of the neck in the visceral space.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 8
Correct
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A 66 year old retired judge has recently undergone a wide local excision and sentinel lymph node biopsy for breast cancer. Which of the factors listed below will provide the most important prognostic information?
Your Answer: Nodal status
Explanation:Even in the era of gene-expression profiling, the nodal status still remains the primary prognostic discriminant in breast cancer patients. The exclusion of node involvement using non-invasive methods could reduce the rate of axillary surgery, thereby preventing from suffering complications.
Lymph node status is highly related to prognosis (chances for survival).
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This question is part of the following fields:
- Breast And Endocrine Surgery
- Generic Surgical Topics
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Question 9
Correct
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A 25-year-old woman is undergoing an appendicectomy for perforated appendicitis. What is the single most important modality for reducing the risks of postoperative wound infection?
Your Answer: Perioperative administration of antibiotics
Explanation:Perioperative administration of antibiotics is very important for reducing the risks of postoperative wound infection. Clips make infections easier to manage but do not reduce the risks. Drains have no effect on the skin wounds in these cases.
Surgical site infections (SSI) comprise up to 20% of all healthcare-associated infections and at least 5% of patients undergoing surgery will develop an SSI as a result. SSIs may occur following a breach in tissue surfaces and allow normal commensals and other pathogens to initiate infection. The organisms are mostly derived from the patient’s own body.
SSIs are a major cause of morbidity and mortality.
Some preoperative measures that may increase the risk of SSI include:
1. Shaving the wound using a razor (disposable clipper preferred)
2. Tissue hypoxia
3. Delayed administration of prophylactic antibiotics in tourniquet surgerySSIs can be prevented by taking certain precautionary steps pre-, intra-, and postoperatively.
1. Preoperatively:
a. Do not remove body hair routinely
b. If hair needs removal, use electrical clippers (razors increase the risk of infection)
c. Antibiotic prophylaxis if:
– placement of prosthesis or valve
– clean-contaminated surgery
– contaminated surgery2. Intraoperatively:
a. Prepare the skin with alcoholic chlorhexidine (Lowest incidence of SSI)
b. Cover surgical site with dressing3. Postoperatively:
a. Prevention of incisional infection by appropriate cleansing, skin care, and moisture management
b.Tissue viability advice for management of surgical wound healing by secondary intention -
This question is part of the following fields:
- Principles Of Surgery-in-General
- Surgical Technique And Technology
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Question 10
Correct
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A 59-year old gentleman admitted for elective cholecystectomy was found to have a haemoglobin 12.5 g/dl, haematocrit 37%, mean corpuscular volume 90 fl, platelet count 185 × 109/l, and white blood cell count 32 × 109/l; along with multiple, small mature lymphocytes on peripheral smear. The likely diagnosis is:
Your Answer: Chronic lymphocytic leukaemia
Explanation:CLL or chronic lymphocytic leukaemia is the most common leukaemia seen in the Western world. Twice more common in men than women, the incidence of CLL increases with age. About 75% cases are seen in patients aged more than 60 years. The blood, marrow, spleen and lymph nodes all undergo infiltration, eventually leading to haematopoiesis (anaemia, neutropenia, thrombocytopenia), hepatomegaly, splenomegaly and decreased production of immunoglobulin. In 98% cases, CD+5 B cells undergo malignant transformation.
Often diagnosed on blood tests while being evaluated for lymphadenopathy, CLL causes symptoms like fatigue, anorexia, weight loss, pallor, dyspnoea on exertion, abdominal fullness or distension. Findings include multiple lymphadenopathy with minimal-to- moderate hepatomegaly and splenomegaly. Increased susceptibility to infections is seen. Herpes Zoster is common. Diffuse or maculopapular skin infiltration can also be seen in T-cell CLL.
Diagnosis is by examination of peripheral blood smear and marrow: hallmark being a sustained, absolute leucocytosis (>5 ×109/l) and increased lymphocytes in the marrow (>30%). Other findings can include hypogammaglobulinemia (<15% of cases) and, rarely, raised lactate dehydrogenase (LDH). Only 10% cases demonstrate moderate anaemia and/or thrombocytopenia. -
This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 11
Correct
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Which of the following will increase blood pressure and cause hypokalaemia?
Your Answer: Angiotensin II
Explanation:Angiotensin is a peptide that is released in response to a decrease in blood volume and blood pressure. It has multiple functions but mainly acts to cause vasoconstriction, increase BP and release aldosterone from the adrenal cortex. It is a powerful vasoconstrictor and release of aldosterone causes increased retention of sodium and excretion of potassium.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 12
Correct
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A 55-year-old woman died 3 years after a cardiac transplant due to worsening congestive heart failure. Autopsy revealed diffuse hyperplasia of the vascular intima involving the entire length of the coronary arteries. The most probable cause of deterioration of the cardiac function is:
Your Answer: Coronary atherosclerosis
Explanation:Allograft coronary artery disease (CAD) can begin right after the transplant and is the major cause of later death in cardiac transplant recipients. This form of atherosclerosis progresses quickly resulting in allograft failure. Due to lack of premonitory symptoms CAD may lead to sudden death.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 13
Correct
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A 45-year old farmer was referred to the surgical clinic with complaints of pain in his right hypochondrium. Investigations confirmed the diagnosis of hepatocellular carcinoma with malignant ascites. According to you, what is the most likely cause of HCC in this patient?
Your Answer: Aflatoxin
Explanation:Aflatoxins are naturally occurring toxins produced by the Aspergillus fungus (most often, A. flavus and A. parasiticus). These organisms are common and their native habitat is soil, decaying vegetation and grains. They can contaminate the grain before harvest or after storage, more likely in high-humidity (at least 7%) or high temperature environment of after stressful conditions like drought. Aflatoxins are mycotoxins and also carcinogenic. They get metabolized in the liver to an epoxide, aflatoxin M1. High exposure can lead to acute necrosis, cirrhosis or liver carcinoma. These substances can cause haemorrhage, acute liver damage, oedema, and alteration in digestion, absorption and/or metabolism of nutrients. Although humans are susceptible to these toxins like all other animals, they have a high tolerance level and hence, rarely develop acute aflatoxicosis. However, children are particularly susceptible to exposure leading to growth impairment and delayed development. Chronic exposure carries a high risk of hepatic cancer, due to intercalation of its metabolite aflatoxin M1 into the DNA and alkylation of the bases because of its epoxide moiety.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 14
Incorrect
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A 39 year old woman returns from a holiday trip in Nepal and presents to her doctor with painless jaundice. On examination there is no organomegaly and she is not deeply jaundiced. What is most likely cause of her illness?
Your Answer: Malaria
Correct Answer: Hepatitis A infection
Explanation:Hepatitis A is a viral liver disease that can cause mild to severe illness. The hepatitis A virus (HAV) is transmitted through ingestion of contaminated food and water or through direct contact with an infectious person.
The risk of hepatitis A infection is associated with a lack of safe water, and poor sanitation and hygiene (such as dirty hands). Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease and is rarely fatal, but it can cause debilitating symptoms and fulminant hepatitis (acute liver failure), which is often fatal.
Prodrome
In the prodrome, patients may have mild flulike symptoms of anorexia, nausea and vomiting, fatigue, malaise, low-grade fever (usually < 39.5°C), myalgia, and mild headache. Smokers often lose their taste for tobacco, like persons presenting with appendicitis. Icteric phase
In the icteric phase, dark urine appears first (bilirubinuria). Pale stool soon follows, although this is not universal. Jaundice occurs in most (70%-85%) adults with acute HAV infection; it is less likely in children and is uncommon in infants. The degree of icterus also increases with age. Abdominal pain occurs in approximately 40% of patients. Itching (pruritus), although less common than jaundice, is generally accompanied by jaundice.Arthralgias and skin rash, although also associated with acute HAV infection, are less frequent than the above symptoms. Rash more often occurs on the lower limbs and may have a vasculitic appearance.
Relapsing hepatitis A
Relapsing hepatitis A is an uncommon sequela of acute infection, is more common in elderly persons, and is characterized by a protracted course of symptoms of the disease and a relapse of symptoms and signs following apparent resolution. -
This question is part of the following fields:
- Clinical Microbiology
- Principles Of Surgery-in-General
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Question 15
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:
- Basic Sciences
- Physiology
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Question 16
Correct
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A 38 year-old man falls on an outstretched hand. X-rays indicate an anterior dislocation of one of the carpal bones. Which carpal bone is most commonly dislocated?
Your Answer: Lunate
Explanation:The scaphoid bone is the most commonly fractured carpal bone and has an increased risk of avascular necrosis.
The lunate is the most commonly dislocated carpal bone. The displaced bone may compress the median nerve in the carpal tunnel. -
This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 17
Correct
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A 48-year-old male is admitted after his clothing caught fire. He suffers a full-thickness circumferential burn to his lower thigh. He complains of increasing pain in the lower leg and on examination, there is paraesthesia and severe pain in the lower leg. Foot pulses are normal. What is the most likely explanation?
Your Answer: Compartment syndrome
Explanation:Full-thickness circumferential and near-circumferential skin burns result in the formation of a tough, inelastic mass of burnt tissue (eschar). The eschar, by virtue of this inelasticity, results in the burn-induced compartment syndrome. This is caused by the accumulation of extracellular and extravascular fluid within confined anatomic spaces of the extremities or digits. The excessive fluid causes the intracompartmental pressures to increase, resulting in the collapse of the contained vascular and lymphatic structures and, hence, loss of tissue viability.
Most compartment syndromes associated with a burn injury do not present in the immediate postburn period unless there is associated with traumatic injury or the patient presents in a delayed fashion. As such, compartment syndromes after burns are not commonly observed in the emergency department. Instead, they develop during the first 6–12 h of the initial volume resuscitation period as the administered intravascular volume goes into the interstitial and intracellular spaces resulting in tissue oedema in or under the burned tissue.Patients with compartment syndrome typically present with pain whose severity appears out of proportion to the injury. The pain is often described as burning. The pain is also deep and aching in nature and is worsened by passive stretching of the involved muscles. The patient may describe a tense feeling in the extremity. Pain, however, should not be a sine qua non of the diagnosis. In severe trauma, such as an open fracture, it is difficult to differentiate between pain from the fracture and pain resulting from increased compartment pressure.
Paraesthesia or numbness is an unreliable early complaint; however, decreased 2-point discrimination is a more reliable early test and can be helpful to make the diagnosis.
The traditional 5 P’s of acute ischemia in a limb (i.e., pain, paraesthesia, pallor, pulselessness, poikilothermia) are not clinically reliable; they may manifest only in the late stages of compartment syndrome, by which time extensive and irreversible soft tissue damage may have taken place.Escharotomy is the surgical division of the nonviable eschar, which allows the cutaneous envelope to become more compliant. Hence, the underlying tissues have an increased available volume to expand into, preventing further tissue injury or functional compromise
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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 18
Correct
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Which of the following coagulation factors is responsible for the formation of a complex with tissue factor to activate factors IX and X?
Your Answer: Factor VII
Explanation:Factor VII, also known as proconvertin or stable factor, is a vitamin K–dependent protein that plays a central role in haemostasis and coagulation. Tissue factor is a protein that is normally not exposed on the surface of intact blood vessels. Damage to the vascular lumen leads to tissue factor exposure. The exposed tissue factor binds to factor VII. This facilitates the activation of factor VII to factor VIIa.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 19
Correct
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The primary area involved in the pathology of Parkinson's disease is:
Your Answer: Substantia nigra
Explanation:Parkinson’s disease is a degenerative, movement disorder of the central nervous system, and is typically characterized by muscle rigidity, tremor and bradykinesia (in extreme cases, akinesia). Secondary symptoms include high-level cognitive dysfunction and subtle language problems.
Parkinson’s disease is also called ‘primary Parkinsonism’ or ‘idiopathic Parkinson’s disease and is the most common cause of Parkinsonism, a group of similar symptoms. The disorder is caused due to loss of pigmented dopaminergic cells in the pars compacta region of the substantia nigra. -
This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 20
Correct
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Which of the following conditions is characterized by generalised oedema due to effusion of fluid into the extracellular space?
Your Answer: Anasarca
Explanation:Anasarca (or ‘generalised oedema’) is a condition characterised by widespread swelling of the skin due to effusion of fluid into the extracellular space. It is usually caused by liver failure (cirrhosis of the liver), renal failure/disease, right-sided heart failure, as well as severe malnutrition/protein deficiency.
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 21
Incorrect
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A patient with this type of tumour is advised to follow up regularly for monitoring of tumour size as there is a strong correlation with malignant potential and tumour size. Which of the following is the most likely tumour in this patient?
Your Answer: Prostate adenocarcinoma
Correct Answer: Renal adenocarcinoma
Explanation:The distinction between a benign renal adenoma and renal adenocarcinoma is commonly made on the basis of size. Tumours less than 2 cm in size rarely become malignant as opposed to those greater than 3 cm.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 22
Correct
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A urologist makes a transverse suprapubic incision to retrieve a stone from the urinary bladder. Which of the following abdominal wall layers will the surgeon NOT traverse?
Your Answer: Posterior rectus sheath
Explanation:Pfannenstiel incision (a transverse suprapubic incision) is made below the arcuate line. Thus, there is no posterior layer of the rectus sheath here, only the transversalis fascia lines the inner layer of the rectus abdominis. The layers traversed include: skin, superficial fascia (fatty and membranous), deep fascia, anterior rectus sheath, rectus abdominis muscle, transversalis fascia, extraperitoneal connective tissue and peritoneum.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 23
Correct
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In the adult heart, the sinus venosus gives rise to the:
Your Answer: Coronary sinus
Explanation:The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. It exists distinctly only in the embryonic heart (where it is found between the two venae cavae); however, the sinus venosus persists in the adult. In the adult, it is incorporated into the wall of the right atrium to form a smooth part called the sinus venarum, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis. The sinus venosus also forms the SA node and the coronary sinus.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 24
Correct
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What is formed when the ductus deferens unites with the duct of the seminal vesicle?
Your Answer: Ejaculatory duct
Explanation:The deferens is a cylindrical structure with dense walls and an extremely small lumen It is joined at an acute angle by the duct of the seminal vesicles to form the ejaculatory duct, which traverses the prostate behind it’s middle lobe and opens into the prostatic portion of the urethra, close to the orifice of the prostatic utricle.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 25
Correct
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A 64 year old woman with metastatic breast cancer presents with bone pain. Radiological reports show a metastatic lytic lesion in her femoral shaft. The lesion occupies 75 percent of the bone diameter. Which of the following would be the most appropriate step in the management of this patient?
Your Answer: Fixation with intramedullary nail
Explanation:The role of surgery for bone metastasis can be divided into (i) prophylactic fixation to prevent impending pathological fractures, (ii) stabilization of a pathological fractures, (iii) segmental resection of tumours, and (iv) arthroplasty for replacing joints that have been destroyed by a tumour. To this end, orthopaedic surgeons have a vast array of surgical devices and implants in their surgical armamentarium at their disposal. These include plates and screws, intramedullary fixation devices, and tumour endoprostheses.
Even with surgical fixation only 30% of pathological fractures unite. -
This question is part of the following fields:
- Oncology
- Principles Of Surgery-in-General
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Question 26
Correct
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A 57-year-old male smoker noted a lump on his inner lip. Upon physical examination the lump measured more than 2 cm but less than 4 cm in its greatest dimension. He is diagnosed with squamous cell carcinoma of the lip. What is the stage of the patient's cancer according to the TNM staging for head and neck cancers?
Your Answer: T2
Explanation:Head and neck cancer is a group of cancers that starts within the mouth, nose, throat, larynx, sinuses, or salivary glands. The TNM staging system used for head and neck cancers is a clinical staging system that allows physicians to compare results across patients, assess prognosis, and design appropriate treatment regimens. The staging is as follows; Primary tumour (T): Tis: pre-invasive cancer (carcinoma in situ), T0: no evidence of primary tumour, T1: tumour 2 cm or less in its greatest dimension, T2: tumour more than 2 cm but not more than 4 cm, T3: tumour larger than 4 cm, T4: tumour with extension to bone, muscle, skin, antrum, neck, etc and TX: minimum requirements to assess primary tumour cannot be met. Regional lymph node involvement (N): N0: no evidence of regional lymph node involvement, N1: evidence of involvement of movable homolateral regional lymph nodes, N2: evidence of involvement of movable contralateral or bilateral regional lymph nodes, N3: evidence of involvement of fixed regional lymph nodes and NX: Minimum requirements to assess the regional nodes cannot be met. Distant metastases (M): M0: no evidence of distant metastases, M1: evidence of distant metastases and MX: minimum requirements to assess the presence of distant metastases cannot be met. Staging: Stage I: T1 N0 M0, Stage II: T2 N0 M0, Stage III: T2NOMO and T3N1MO, Stage IV: T4N1M0, any TN2M0, any TN3M0, any T and any NM1. The depth of infiltration is predictive of the prognosis. With increasing depth of invasion of the primary tumour, the risk of nodal metastasis increases and survival decreases. The patient in this scenario therefore has a T2 tumour.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 27
Correct
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A terrorist running away from the police was shot in the back. The bullet hit his left lung halfway between its apex and the diaphragmatic surface. Which part of the lung was most likely to be injured?
Your Answer: Inferior lobe
Explanation:The oblique fissure of the left lung is so sharp that the posterior surface of the left lung is mostly composed of the inferior lobe so that the point halfway between the apex and the diaphragmatic surface of the lung would result in injury to the inferior lobe.
The hilum is the point on the medial surface of the lung where the structures that form the root of the lung enter and leave the lung.
The lingual on the other hand is part of the superior lobe of the left lung and it is part of the anterior and superior sides of the lung.
The middle lobe is only found on the right lung. -
This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 28
Incorrect
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Etoposide is a chemotherapeutic agent used in the treatment of different types of cancer. Which of the following is the correct indication for this drug?
Your Answer: Hairy cell leukaemia
Correct Answer: Lung cancer
Explanation:Etoposide phosphate is an inhibitor of the enzyme topoisomerase II. It is used as a form of chemotherapy for malignancies such as lung cancer, testicular cancer, lymphoma, non-lymphocytic leukaemia and glioblastoma multiforme. Side effects are very common and can include low blood cell counts, vomiting, loss of appetite, diarrhoea, hair loss, and fever.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 29
Incorrect
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Below which level of the spinal cord will the inferior gluteal nerve be unaffected?
Your Answer: S1
Correct Answer: S3
Explanation:The inferior gluteal nerve arises from the dorsal divisions of the fifth lumbar and first and second sacral nerves. According to this fact any lesion at or below the S3 will not affect the inferior gluteal nerve.
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This question is part of the following fields:
- Anatomy
- Basic Sciences
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Question 30
Correct
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A 34-year-old Asian male presents with cervical lymphadenopathy. The patient is suspected to have tuberculous lymphadenopathy. Excision biopsy of one of the nodes showed granulomatous inflammation. Which histopathologic feature is most likely consistent with the diagnosis of tuberculosis?
Your Answer: Caseation necrosis
Explanation:The granulomas of tuberculosis tend to contain necrosis (caseating tubercles), but non-necrotizing granulomas may also be present. Multinucleated giant cells with nuclei arranged like a horseshoe (Langhans giant cells) and foreign body giant cells are often present, but are not specific for tuberculosis. A definitive diagnosis of tuberculosis requires identification of the causative organism by microbiological cultures.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 31
Correct
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A chloride sweat test was performed on a 13-year-old boy. Results indicated a high likelihood of cystic fibrosis. This diagnosis is associated with a higher risk of developing which of the following?
Your Answer: Bronchiectasis
Explanation:Cystic fibrosis is a life-threatening disorder that causes the build up of thick mucus in the lungs, digestive tract, and other areas of the body. It is a hereditary autosomal-recessive disease caused by mutations of the CFTR gene. Cystic fibrosis eventually results in bronchiectasis which is defined as a permanent dilatation and obstruction of bronchi or bronchioles.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 32
Correct
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A 27-yeaar-old woman is diagnosed with candidiasis and prescribed fluconazole. What is the mechanism of action of fluconazole?
Your Answer: Inhibits cytochrome P450
Explanation:Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. Like other imidazole- and triazole-class antifungals, fluconazole inhibits the fungal cytochrome P450 enzyme, 14-demethylase. It is used to treat candidiasis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, dermatophytosis, and pityriasis versicolor.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 33
Incorrect
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Chest X-ray of a 45-year old gentleman with a week history of pleurisy showed a small pneumothorax with moderate-sized pleural effusion. Arterial blood gas analysis showed p(CO2) = 23 mmHg, p(O2) = 234.5 mmHg, standard bicarbonate = 16 mmol/l. What are we most likely dealing with?
Your Answer: Compensated metabolic acidosis
Correct Answer: Compensated respiratory alkalosis
Explanation:Normal pH with low p(CO2) and low standard bicarbonate could indicate either compensated respiratory alkalosis or a compensated metabolic acidosis. However, the history of hyperventilation for 5 days (pleurisy) favours compensated respiratory alkalosis. Compensated metabolic acidosis would have been likely in a diabetic patient with fever, vomiting and high glucose (diabetic ketoacidosis).
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This question is part of the following fields:
- Basic Sciences
- Physiology
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Question 34
Correct
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A teenager is taken to his doctor because his mother noticed a patch of hair overlying his lower lumbar spine and a birth mark at the same location. Neurological examination of the lower limbs is normal. What is the likely diagnosis?
Your Answer: Spina bifida occulta
Explanation:Answer: Spina bifida occulta
Spina Bifida Occulta is the mildest type of spina bifida. It is sometimes called “hidden” spina bifida. With it, there is a small gap in the spine, but no opening or sac on the back. The spinal cord and the nerves usually are normal. Many times, Spina Bifida Occulta is not discovered until late childhood or adulthood. This type of spina bifida usually does not cause any disabilities.
Eighty percent of those with a spinal cord problem will have skin over the defect with:
a hairy patch
a fatty lump
a haemangioma—a red or purple spot made up of blood vessels
a dark spot or a birthmark—these are red and don’t include blue-black marks, called “Mongolian spots”
a skin tract (tunnel) or sinus—this can look like a deep dimple, especially if it’s too high (higher than the top of the buttocks crease), or if its bottom can’t be seen
a hypopigmented spot—an area with less skin colour.Myelocele is herniation of spinal cord tissue through a defect in a region of the vertebral column. The protrusion of the tissue is flush with the level of the skin surface. In myelocele, the spinal cord is exposed so that nerve tissue lies exposed on the surface of the back without even a covering of skin or of the meninges, the membranous tissue surrounding the brain and spinal cord.
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This question is part of the following fields:
- Generic Surgical Topics
- Orthopaedics
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Question 35
Correct
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A patient with testicular seminoma has the following tumour markers: LDH 1.3 times the reference levels, β-hCG 4500 mIU/ml and AFP 875 ng/ml. What's the serum tumour marker stage in this case?
Your Answer: S1
Explanation:According to AJCC guidelines, the serum tumour marker staging is the following:
S0: marker studies within normal limits
S1: lactate dehydrogenase (LDH) less than 1.5 times the reference range, beta-human chorionic gonadotrophin (β-hCG) <5000 mIU/ml, and alpha-fetoprotein (AFP) <1000 ng/ml
S2: LDH 1.5–10 times the reference range, β-hCG 5000–50,000 mIU/ml or AFP 1000–10,000 ng/ml
S3: LDH greater than 10 times the reference range, β-hCG >50,000 mIU/ml or AFP >10,000 ng/ml.
According to this, the patient’s tumour belongs to the S1 stage. -
This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 36
Correct
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Which tumour marker is associated with medullary carcinoma of thyroid?
Your Answer: Calcitonin
Explanation:Medullary carcinoma of thyroid accounts for 3% of thyroid cancers. It arises from the parafollicular cells (C cells) of the thyroid gland that produce calcitonin. It is often familial and caused by mutation of ret proto-oncogene, but can occasionally be sporadic. The familial cases can also occur as part of MEN syndromes IIA and IIB. The high calcitonin leads to down-regulation of the receptors, which does not affect the calcium levels significantly. Medullary carcinoma of thyroid shows characteristic amyloid deposits that stain positively with Congo red. The initial presentation consists of an asymptomatic thyroid nodule. Many cases are diagnosed due to routine screening of relatives of patients with MEN IIA and IIB. Medullary carcinoma can also cause ectopic production of other hormones/peptides such as adrenocorticotrophic hormone, vasoactive intestinal polypeptide, kallikreins and serotonin.
Metastasis from medullary carcinoma spread via the lymphatics to cervical and mediastinal nodes, and can also affect the liver, lungs and bone. Diagnosis is by raised serum calcitonin levels. A provocative test with calcium (15 mg/kg intravenously over 4 hours) also aids in diagnosis by leading to excessive secretion of calcitonin. X-ray might also show dense, conglomerate calcification.
CA-125 is frequently elevated in ovarian carcinomas. CA 15-3 is often associated with breast carcinomas. Alpha-fetoprotein is seen raised in hepatomas and gonadal tumours. Elevated HCG is associated with normal pregnancies, gonadal tumours, and choriocarcinomas. Thyroglobulin is used for surveillance in papillary carcinoma of thyroid. CA 19-9 is used in the management of pancreatic cancer. -
This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 37
Correct
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A 70-year-old man suffers an ischaemic stroke and develops a left homonymous hemianopia. Where is the likely infarct?
Your Answer: Right occipital lobe
Explanation:The man has a left homonymous hemianopia which means he is unable to view objects in the left visual field. This information is processed by the right primary visual cortex which lies in the right occipital lobe.
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This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 38
Incorrect
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A 28 years old women presents with a history of chronic cough with fever for the past 2 months. A chest x ray revealed a diffuse bilateral reticulonodular pattern. A transbronchial biopsy was performed and histological examination showed focal areas of inflammation with epithelioid macrophages, Langhans cells and lymphocytes. Which of the immune reaction is responsible for this?
Your Answer: Type II hypersensitivity
Correct Answer: Type IV hypersensitivity
Explanation:A reactivated tuberculosis with granuloma formation is characteristic of type IV reaction. It is also called a delayed type of hypersensitivity reaction and takes around 2-8 days to deliver. It is a cell mediated response with the involvement of CD8 and CD4 cells and the release of IL-1 from macrophages that further activate these CD cells.
Granulomatous reactions are mostly cell-mediated.
Type I reactions are allergic and anaphylactic reactions and type II are complement-mediated immune reactions. -
This question is part of the following fields:
- Basic Sciences
- Pathology
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Question 39
Correct
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A 33 year old man is diagnosed with CA caecum. Thorough history taking reveals that his mother developed uterine cancer at 39 years of age and his maternal uncle died at 38 due to colonic cancer. Which of the following operative options would be the most suitable for this patient?
Your Answer: Panproctocolectomy
Explanation:Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is a type of inherited cancer syndrome associated with a genetic predisposition to different cancer types. People who have Lynch syndrome have a significantly increased risk of developing colorectal cancer. There is also an increased risk of developing other types of cancers, such as endometrial (uterine), stomach, breast, ovarian, small bowel (intestinal), pancreatic, prostate, urinary tract, liver, kidney, and bile duct cancers. Alterations in several genes involved in DNA mismatch repair that have been linked to Lynch syndrome. They include the genes of MLH1, MSH2, MSH6, PMS2, and EPCAM. A mutation (alteration) in any of these genes gives a person an increased lifetime risk of developing colorectal cancer and other related cancers.
Women also have an increased risk of developing endometrial and ovarian cancers. The safest operative strategy is a pancolectomy and end ileostomy.
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This question is part of the following fields:
- Colorectal Surgery
- Generic Surgical Topics
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Question 40
Correct
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A 25-year-old intravenous drug user is found to have a femoral abscess. He is also febrile with a temperature of 39°C and has a pansystolic murmur loudest at the left sternal edge in the 4th intercostal space. Which of the following is the most likely underlying lesion?
Your Answer: Tricuspid regurgitation
Explanation:Intravenous drug users are at a high risk of right-sided cardiac valvular endocarditis. The character of the murmur described in the scenario fits with the diagnosis of tricuspid valve endocarditis.
Other listed options are ruled out because:
1. Aortic regurgitation—Early diastolic murmur
2. Mitral regurgitation—Pansystolic murmur
3. Aortic valve stenosis—Ejection systolic murmur
4. Tricuspid valve stenosis—Mid-diastolic murmur -
This question is part of the following fields:
- Generic Surgical Topics
- Vascular
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SESSION STATS - PERFORMANCE PER SPECIALTY
