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Question 1
Incorrect
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Which of the following causes type 1 diabetes mellitus?
Your Answer: Monogenic defects in beta-cell function results in insulin deficiency
Correct Answer: Autoimmune destruction of beta-cells results in insulin deficiency
Explanation:Type 1 diabetes mellitus results from autoimmune destruction of the insulin-producing beta cells in the islets of Langerhans. This process occurs in genetically susceptible subjects, is probably triggered by one or more environmental agents, and usually progresses over many months or years during which the subject is asymptomatic and euglycemic.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 2
Incorrect
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Regarding drug interactions with erythromycin, which of the following statements is INCORRECT:
Your Answer: Erythromycin increases plasma levels of carbamazepine.
Correct Answer: Erythromycin decreases plasma levels of warfarin.
Explanation:Erythromycin and clarithromycin inhibit cytochrome P450-mediated metabolism of warfarin, phenytoin and carbamazepine and may lead to accumulation of these drugs. There is an increased risk of myopathy (due to cytochrome P450 enzyme CYP3A4 inhibition) if erythromycin or clarithromycin is taken with atorvastatin or simvastatin. Erythromycin increases plasma concentrations of theophylline, and theophylline may also reduce absorption of oral erythromycin. All macrolides can prolong the QT-interval and concomitant use of drugs that prolong the QT interval is not recommended.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 3
Incorrect
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You examine a 78-year-old man who has been diagnosed with chronic lymphocytic leukaemia (CLL).
What is the MAIN contributory factor in this condition's immunodeficiency?Your Answer: Thrombocytopenia
Correct Answer: Hypogammaglobulinemia
Explanation:Immunodeficiency is present in all patients with chronic lymphocytic leukaemia (CLL), though it is often mild and not clinically significant. Infections are the leading cause of death in 25-50 percent of CLL patients, with respiratory tract, skin, and urinary tract infections being the most common.
Hypogammaglobulinemia is the most common cause of immunodeficiency in CLL patients, accounting for about 85 percent of all cases.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 4
Incorrect
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Captopril should not be used if you have any of the following conditions:
Your Answer:
Correct Answer: Renal artery stenosis
Explanation:Contraindications indications of Captopril include:
– Bilateral renal artery stenosis
– Hypersensitivity to ACE inhibitors
– Anuria
– History of ACEI-induced angioedema
– Hereditary or idiopathic angioedema
– Co-administration of Neprilysin inhibitors (e.g., sacubitril) with ACE inhibitors may increase angioedema risk; do not administer ACE inhibitors within 36 hours of switching to or from sacubitril/valsartan.
If ACE inhibitors are used, they should be initiated only under specialist supervision and renal function should be monitored regularly. ACE inhibitors should also be used with particular caution in patients who may have undiagnosed and clinically silent renovascular disease. This includes patients with peripheral vascular disease or those with severe generalised atherosclerosis. -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 5
Incorrect
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Atrial natriuretic peptide (ANP) is primarily produced in response to:
Your Answer:
Correct Answer: An increase in intravascular fluid volume
Explanation:Atrial natriuretic peptide (ANP) is released from cardiac atrial muscle cells in response to atrial stretch caused by an increase in intravascular fluid volume and is also produced in collecting duct cells.
Atrial natriuretic peptide acts to inhibit sodium reabsorption in the distal nephron. -
This question is part of the following fields:
- Physiology
- Renal
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Question 6
Incorrect
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Which of the following statements is correct with regards to immunoglobulin?
Your Answer:
Correct Answer: The isotype of immunoglobulin is determined by the heavy chain.
Explanation:The composition of immunoglobulin molecules is two identical heavy and two identical light chains. These chains are linked by disulphide bridges and are each have highly variable regions which give the immunoglobulin its specificity. In addition, they have constant regions and there is virtual complete correspondence in amino acid sequence in all antibodies of a given isotype.
Five isotypes of immunoglobulin exist – these are IgG, IgA, IgM, IgE and IgD. They are determined by the heavy chain (gamma, alpha, mu, epsilon or delta respectively). The light chains are either kappa or lambda. -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 7
Incorrect
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A 49-year-old woman with haemoglobin of 6 g/dL following persistent vaginal bleeding receives blood transfusion. She developed pain and burning at her cannula site and complains of a feeling of “impending doom”, nausea, and severe back pain shortly after transfusion was started. Her temperature is 38.9ºC.
What is the most appropriate treatment?Your Answer:
Correct Answer: Stop the transfusion and administer IV fluids
Explanation:Acute haemolytic transfusion reactions present with: Feeling of ‘impending doom’ as the earliest symptom, fever and chills, pain and warmth at transfusion site, nausea and vomiting, back, joint, and chest pain. Transfusion should be stopped immediately and IV fluid (usually normal saline) administered.
Supportive measures and paracetamol can be given since patient has fever but it is not the immediate first step.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 8
Incorrect
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Regarding the heart sounds in the cardiac cycle, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The third heart sound is caused by filling of an abnormally stiff ventricle in atrial systole.
Explanation:Heart Sound – Phase of Cardiac Cycle – Mechanical Event:
First heart sound – Start of systole – Caused by closure of the atrioventricular (mitral & tricuspid) valves
Second heart sound – End of systole – Caused by closure of the semilunar (aortic and pulmonary) valves
Third heart sound – Early diastole – Caused by rapid flow of blood from the atria into the ventricles during the ventricular filling phase
Fourth heart sound – Late diastole – Caused by filling of an abnormally stiff ventricle in atrial systole -
This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Incorrect
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You are about to perform an emergency pericardiocentesis on a 26-year-old male who was involved in a car accident and is suspected of having cardiac tamponade due to signs of hypotension, muffled heart sounds, and distended neck veins. Where should you insert the needle to relieve tamponade?
Your Answer:
Correct Answer: Inferior and to the left of the xiphochondral junction
Explanation:Pericardiocentesis is a procedure that removes excess fluid from the pericardium. As a result, it’s used in cases of cardiac tamponade, which occurs when there’s too much fluid in the space around the heart.
During the procedure, a needle and a small catheter are inserted 1 to 2 cm inferior and to the left of the xiphochondral junction into the pericardial cavity.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 10
Incorrect
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A 18 year old university student develops facial swelling and dark frothy urine. Urine dipstick demonstrates haematuria and proteinuria. Approximately 3 weeks ago, he was treated with oral antibiotics for a sore throat. His condition is most likely to be secondary to infection with:
Your Answer:
Correct Answer: Streptococcus pyogenes
Explanation:Post-streptococcal glomerulonephritis is a postinfectious immune-mediated reaction secondary to infection with Streptococcus pyogenes. It typically occurs 2 weeks or more after acute/initial infection, and presents with haematuria, reduced urine output, peripheral oedema, proteinuria, and hypertension. Permanent kidney damage is rare.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 11
Incorrect
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Which of the following muscles is NOT involved in depression of the mandible:
Your Answer:
Correct Answer: Masseter
Explanation:Depression of the mandible is generated by the digastric, geniohyoid, mylohyoid and lateral pterygoid muscles on both side, assisted by gravity. The lateral pterygoid muscles are also involved as this movement also involves protraction of the mandible. The masseter muscle is a powerful elevator of the mandible.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 12
Incorrect
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A patient has suffered a nerve injury that has caused weakness of the pectoralis minor muscle.
Pectoralis minor receives its innervation from which of the following nerves? Select ONE answer only.Your Answer:
Correct Answer: Medial pectoral nerve
Explanation:Pectoralis minor is a thin, triangular muscle that is situated in the upper chest. It is thinner and smaller than pectoralis major. It is innervated by the medial pectoral nerve.
The origin of pectoralis minor is the 3rdto the 5thribs, near the costal cartilages. It inserts into the medial border and superior surface of the coracoid process of the scapula.
The main action of pectoralis minor is to draw the scapula inferiorly and anteriorly against the thoracic wall. This serves to stabilise the scapula. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 13
Incorrect
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A 78-year-old man develops renal impairment and hearing loss after inpatient management for sepsis.
Which of these antibiotics is most likely to have been used?Your Answer:
Correct Answer: Gentamicin
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA, and thus prevents initiation of protein synthesis.
Two of its most notable side effects are reversible nephrotoxicity(caused by the inhibition of protein synthesis in renal cells, which causes acute tubular necrosis) and hearing loss (caused by damage to the vestibular apparatus of the inner ear).
Both side effects are dose-related and occur commonly in the elderly.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 14
Incorrect
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Digoxin is contraindicated in all of the following EXCEPT for:
Your Answer:
Correct Answer: Asthma
Explanation:Digoxin is contraindicated in:Supraventricular arrhythmias associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndromeVentricular tachycardia or fibrillationHeart conduction problems e.g. second degree or intermittent complete heart blockHypertrophic cardiomyopathy (unless concomitant atrial fibrillation and heart failure but should be used with caution)
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 15
Incorrect
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Which of the following statements concerning hepatitis D is TRUE:
Your Answer:
Correct Answer: It can only be transmitted with, or to somebody who is infected with, Hepatitis B.
Explanation:Hepatitis D virus (HDV) is an RNA virus that was discovered in 1977 and is structurally unrelated to the hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV) viruses. HDV causes a unique infection that requires the assistance of HBV viral particles to replicate and infect hepatocytes. Its clinical course is varied and ranges from acute, self-limited infection to acute, fulminant liver failure. Chronic liver infection can lead to end-stage liver disease and associated complications (including accelerated fibrosis, liver decompensation, and hepatocellular carcinoma).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 16
Incorrect
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A patient with rash is examined. He has some redness of the skin that blanches when finger pressure is applied.
What is the best description of this rash that you have found on examination?Your Answer:
Correct Answer: Erythema
Explanation:Erythema is redness of the skin or mucous membranes caused by hyperaemia of superficial capillaries caused by skin injury, infection or inflammation. Erythema blanches when pressure is applied whereas ecchymosis, purpura and petechiae do not.
Ecchymosis are discolouration of the skin or mucous membranes caused by extravasation of blood. They are usually red or purple in colour and measure greater than 1 cm in diameter and do not blanch on applying pressure.
A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
Petechiae are discolouration of the skin measuring less than 3 mm in diameter
Purpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 17
Incorrect
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Regarding basophils, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: They are the second most common type of granulocyte.
Explanation:Basophils are only occasionally seen in normal peripheral blood comprising < 1% of circulating white cells. However, they are the largest type of granulocyte. They have many dark cytoplasmic granules which overlie the nucleus and contain heparin and histamine. They have immunoglobulin E (IgE) attachment sites and their degranulation is associated with histamine release. Basophils are very similar in both appearance and function to mast cells.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 18
Incorrect
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A 18 year old male presents to the GP with painless asymmetrical cervical lymphadenopathy. Histological examination of a biopsied lymph node demonstrates Reed-Sternberg cells. What is the most likely diagnosis:
Your Answer:
Correct Answer: Hodgkin lymphoma
Explanation:Hodgkin’s lymphoma is a malignant tumour of the lymphatic system that is characterised histologically by the presence of Reed-Sternberg cells (multinucleated giant cells). The peak incidence is in young adults aged 20-35, and there is a slight male predominance.
The following are recognised risk factors for Hodgkin’s lymphoma:
Male gender
Age 20-35
Positive family history
Epstein-Barr virus infection
Immunosuppression including HIV infection
Prolonged use of human growth hormone
Most patients present with an enlarged, but otherwise asymptomatic lymph node. The most commonly affected lymph nodes are in the supraclavicular and lower cervical areas. Other common clinical features include shortness of breath and chest discomfort secondary to mediastinal mass. Mediastinal masses are sometimes discovered as incidental findings on routine chest X-rays. Approximately 30% of patients with Hodgkin’s lymphoma develop splenomegaly.
‘B’ symptoms occur in approximately 25% of patients. The ‘B’ symptoms of Hodgkin’s lymphoma are:
Fever (>38ºC)
Night sweats
Weight loss (>10% over 6 months)
Pain after alcohol consumption is a pathognomonic sign of Hodgkin’s lymphoma, it is, however, not a ‘B’ symptom. It is rare though, only occurring in 2-3% of patients with Hodgkin’s lymphoma.The Ann Arbour clinical staging is as follows:
Stage I: one involved lymph node group
Stage II two involved lymph node groups on one side of the diaphragm
Stage III: lymph node groups involved on both sides of the diaphragm
Stage IV: Involvement of extra-nodal tissues, such as the liver or bone marrow
Diagnosis is made by lymph node biopsy, which should be taken from a sufficiently large specimen or excisional biopsy, as opposed to a fine needle biopsy. The Reed-Sternberg cell is the most useful diagnostic feature. This is a giant cell with twin mirror-image nuclei and prominent ‘owl’s eye’ nucleoli.
The Reed-Sternberg cell of Hodgkin’s Lymphoma
Histological typing depends upon the other cells within the diseased tissue. Nodular sclerosing is the most common type of Hodgkin’s lymphoma. Lymphocyte-depleted and lymphocyte-predominant are rare subtypes.
The majority of cases can be successfully treated, and unlike many other malignancies even if the first-line treatment fails, a cure can often be achieved with second-line therapies. Stage 1 Hodgkin’s lymphoma is usually treated with radiotherapy alone, but more advanced stages require combination chemotherapy. In localised disease treated with irradiation, there is a 5-year survival rate of greater than 80%. In disseminated disease treated with chemotherapy, the 5-year survival falls to around 50%. Overall, a 5-year survival of >70% should be achieved. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 19
Incorrect
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Osteoclasts are a type of bone cell that are critical in the maintenance, repair and remodelling of bones.
Which of the following inhibits osteoclast activity? Select ONE answer only.Your Answer:
Correct Answer: Calcitonin
Explanation:Osteoclasts are a type of bone cell that breaks down bone tissue. This is a critical function in the maintenance, repair and remodelling of bones. The osteoclast disassembles and digests the composite of hydrated protein and minerals at a molecular level by secreting acid and collagenase. This process is known as bone resorption and also helps to regulate the plasma calcium concentration.
Osteoclastic activity is controlled by a number of hormones:
1,25-dihydroxycholecalciferol increases osteoclastic activity
Parathyroid hormone increases osteoclastic activity
Calcitonin inhibits osteoclastic activity
Bisphosphonates are a class of drug that slow down and prevent bone damage. They are osteoclast inhibitors. -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 20
Incorrect
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A 66-year-old female presents to the Emergency Department with a nose bleed. She says that she has been having frequent episodes of nose bleeds over the past four months, along with increasing fatigue and some weight loss. On examination, she has a diffuse petechial rash and hypertrophy of the gingiva.
Which one of the following conditions is this patient most likely to have?Your Answer:
Correct Answer: Acute myeloid leukaemia (AML)
Explanation:The history of nosebleeds and fatigue, and gingival hyperplasia presents a typical picture of acute myeloid leukaemia. Leukemic infiltrates within the gingiva cause hypertrophy and distinguish this condition from other types of leukaemia. The fatigue is secondary to anaemia, while the nosebleeds are caused by thrombocytopenia secondary to leukemic infiltration of bone marrow. Patients may also report frequent infections secondary to neutropenia and hepatosplenomegaly.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 21
Incorrect
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You are going to prescribe a NSAID to a 50-year-old male patient for his back pain. Which of the following NSAIDs is least likely to cause gastrointestinal side effects:
Your Answer:
Correct Answer: Ibuprofen
Explanation:NSAIDs are associated with serious gastrointestinal irritation and drug-induced ulcers.
Among the NSAIDs included in the choices, ibuprofen has the lowest risk.
Piroxicam, ketoprofen, and ketorolac trometamol are associated with the highest risk of serious upper gastrointestinal side effects.
Indomethacin, diclofenac, and naproxen are associated with an intermediate risk of serious upper gastrointestinal side effects.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 22
Incorrect
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A thyroid function test is done for a 55-year-old woman with non-specific symptoms, the results are shown below:
TSH = 5.2
Free T4 is normal
Free T3 is normal
The most likely diagnosis in this patient is?
Your Answer:
Correct Answer: Subclinical hypothyroidism
Explanation:Hypothyroidism is diagnosed using the results of thyroid function tests (TFTs).
In the early stages of the disease, the earliest biochemical change noticed is a rise in thyroid-stimulating hormone (TSH) levels. Free triiodothyronine (T3) and thyroxine (T4) levels are usually normal.
In primary hypothyroidism, the serum TSH level is usually greater than 10 mU/L, and free T4 levels are below the reference range.
Subclinical hypothyroidism is diagnosed when the serum TSH level is above the reference range, and the free T4 levels are within the reference range. The test should, however, be repeated after 3-6 months to exclude transient causes of raised TSH.
In summary, how to interpret TFTs in cases of suspected hypothyroidism is shown below:
Subclinical hypothyroidism
TSH is raised
Free T4 is normal
Free T3 is normalPrimary hypothyroidism
TSH is raised
Free T4 is lowered
Free T3 is lowered or normalSecondary hypothyroidism
TSH is lowered or normal
Free T4 is lowered
Free T3 is lowered or normal -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 23
Incorrect
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Regarding the abductor pollicis longus, which of the following statements is true?
Your Answer:
Correct Answer: It extends the thumb at the carpometacarpal joint
Explanation:Abductor pollicis longus is a muscle found in the posterior compartment of the forearm. It is one of the five deep extensors in the forearm, along with the supinator, extensor pollicis brevis, extensor pollicis longus and extensor indicis.
Abductor pollicis longus is innervated by the posterior interosseous nerve (C7, C8), which is a continuation of the deep branch of the radial nerve. The radial nerve is a branch of the posterior cord of the brachial plexus.
Blood supply to the abductor pollicis longus muscle comes from the interosseous branches of the ulnar artery.
Acting alone or with abductor pollicis brevis, abductor pollicis longus pulls the thumb away from the palm. More specifically, it produces (mid-) extension and abduction of the thumb at the first metacarpophalangeal joint. This action is seen in activities such as bowling and shovelling.
Working together with the long and short extensors of the thumb, the muscle also helps to fully extend the thumb at the metacarpophalangeal joint. This action is important for loosening the hand grip, for example, when letting go of objects previously being held. Abductor pollicis longus also helps to abduct the hand (radial deviation) at the radiocarpal joint.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 24
Incorrect
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Which coronary artery is mostly likely affected if an ECG shows a tombstone pattern in leads V2, V3 and V4?
Your Answer:
Correct Answer: Left anterior descending artery
Explanation:Tombstoning ST elevation myocardial infarction can be described as a STEMI characterized by tombstoning ST-segment elevation. This myocardial infarction is associated with extensive myocardial damage, reduced left ventricle function, serious hospital complications and poor prognosis. Tombstoning ECG pattern is a notion beyond morphological difference and is associated with more serious clinical results.
Studies have shown that tombstoning is more commonly found in anterior than non-anterior STEMI, thus, higher rates of left anterior descending artery disease are observed in patients with tombstoning pattern.
The following ECG leads determine the location and vessels involved in myocardial infarction:
ECG Leads Location Vessel involved
V1-V2 Septal wall Left anterior descending
V3-V4 Anterior wall Left anterior descending
V5-V6 Lateral wall Left circumflex artery
II, III, aVF Inferior wall Right coronary artery (80%) or Left circumflex artery (20%)
I, aVL High lateral wall Left circumflex artery
V1, V4R Right ventricle Right coronary artery
V7-V9 Posterior wall Right coronary artery -
This question is part of the following fields:
- Anatomy
- Thorax
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Question 25
Incorrect
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A patient presents with a cough, productive of green sputum and fever. He was commenced on antibiotics 4 days earlier, but his condition has worsened. There is a documented history of penicillin allergy, and the GP prescribed erythromycin.
Erythromycin exert its pharmacological effect by binding to?
Your Answer:
Correct Answer: The 50S subunit of the bacterial ribosome
Explanation:Macrolides are bacteriostatic antibiotics. They act by binding to the 50S subunit of the bacterial ribosome and inhibit translocation, therefore, inhibiting protein synthesis.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 26
Incorrect
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A blood transfusion is given to a 52-year-old woman. She develops chills and rigours shortly after the transfusion begins.
The following are her observations: Temperature 40°C, HR 116 bpm, BP 80/48, SaO 2 97 percent on air.
Which of the following treatments is the most appropriate?Your Answer:
Correct Answer: Stop the transfusion and administer antibiotics
Explanation:Bacterial infections are common in the following situations:
Platelet transfusions are associated with a higher risk of bacterial infection (as platelets are stored at room temperature)
Immersion in a water bath thawed previously frozen components.
Components of red blood cells that have been stored for several weeks
Gram-positive and Gram-negative bacteria have both been linked to transfusion-transmitted bacterial infection, but Gram-negative bacteria are linked to a higher rate of morbidity and mortality.
Yersinia enterocolitica is the most common bacterial organism linked to transfusion-transmitted bacterial infection. This organism can multiply at low temperatures while also utilising iron as a nutrient. As a result, it’s well-suited to proliferating in blood banks.The following are some of the most common clinical signs and symptoms of a bacterial infection transmitted through a blood transfusion. These symptoms usually appear shortly after the transfusion begins:
Fever is very high.
Rigours and chills
Vomiting and nausea
Tachycardia
Hypotension
Collapse of the circulatory systemIf a bacterial infection from a transfusion is suspected, the transfusion should be stopped right away. Blood cultures and a Gram stain should be requested, as well as broad-spectrum antibiotics. In addition, the blood pack should be returned to the blood bank for an urgent culture and Gram-stain.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 27
Incorrect
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All of the following typically occurs as part of normal passive expiration except:
Your Answer:
Correct Answer: Contraction of the internal intercostal muscles
Explanation:Passive expiration is produced primarily by relaxation of the inspiratory muscles (diaphragm and external intercostal muscles) in addition to the elastic recoil of the lungs.
In expiration, several movements occur. There are:
1. depression of the sternal ends of the ribs (‘pump handle’ movement),
2. depression of the lateral shafts of the ribs (‘bucket handle’ movement) and
3. elevation of the diaphragm.
These result in a reduction of the thorax in an anteroposterior, transverse and vertical direction respectively. There is then a decreased intrathoracic volume and increased intrathoracic pressure and air is forced out of the lungs. -
This question is part of the following fields:
- Anatomy
- Thorax
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Question 28
Incorrect
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Regarding Gaussian sample distribution, which of the following statements is false?
Your Answer:
Correct Answer: It can be skewed left or right
Explanation:Gaussian distribution, also known as normal distribution, is the most important probability distribution in statistics because it fits many natural phenomena. The normal distribution is a probability function that describes how the values of a variable are distributed. Below are its characteristics:
(1) Bell-shaped and symmetrical about the mean
(2) The mean, median, mode are all equal
(3) The total area under the curve and above the x-axis is equal to 1
(4) It has long tapering tails extending infinitely but never touching the x-axis
(5) It is determined by its parameters: its mean and standard deviation
(6) The standard deviation becomes a more meaningful quality than merely being a measure of dispersionThe mean is the most common measure of central tendency. It is the sum of all observed values divided by the number of observation, and is also known as the ‘average’.
The median is the value that falls in the middle position when the observations are ranked in order from the smallest to the largest. If the number of observations is odd, the median is the middle number. If it is even, the median is the average of the two middle numbers.
The mode is the value that occurs with the greatest frequency in a set of observations, and is commonly used in public health statistics, such as the top 10 causes of mortality.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 29
Incorrect
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Question 30
Incorrect
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A possible diagnosis of Cushing's illness is being investigated in an overweight patient with resistant hypertension. A CRH (corticotropin-releasing hormone) test is scheduled.
Which of the following statements about corticotropin-releasing hormone is correct?Your Answer:
Correct Answer: It is produced by cells within the paraventricular nucleus of the hypothalamus
Explanation:Corticotropin-releasing hormone (CRH) is a neurotransmitter and peptide hormone. It is generated by cells in the hypothalamic paraventricular nucleus (PVN) and released into the hypothalamo-hypophyseal portal system at the median eminence through neurosecretory terminals of these neurons. Stress causes the release of CRH.
The CRH is carried to the anterior pituitary through the hypothalamo-hypophyseal portal system, where it activates corticotrophs to release adrenocorticotropic hormone (ACTH). Cortisol, glucocorticoids, mineralocorticoids, and DHEA are all produced in response to ACTH.
Excessive CRH production causes the size and quantity of corticotrophs in the anterior pituitary to expand, which can lead to the creation of a corticotrope tumour that generates too much ACTH.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 31
Incorrect
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You see a 30-year-old man who has come to the department with a very tender right elbow. On examination, the elbow is very hot and red, and appears to be acutely inflamed.
Which SINGLE statement regarding acute inflammation is FALSE?Your Answer:
Correct Answer: Reduced extravascular osmotic pressure leads to oedema
Explanation:Inflammation can be divided intoacute inflammation, which occurs over seconds, minutes, hours, and days, andchronic inflammation, which occurs over longer periods.
Acute inflammationcommences within seconds or minutes following the injury of tissues. There are numerous potential stimuli for an acute inflammatory response including infections (bacterial, viral, fungal, parasitic), tissue necrosis, foreign bodies, and Immune reactions (hypersensitivity reactions). The chief cell type of acute inflammation is the neutrophil.
There are three main processesthat occur in the acute inflammatory response:
Increased blood flow
Increased capillary permeability
Neutrophil migration
1. Increased blood flow:
Vasoactive mediators are released, such as nitric oxide, histamine, bradykinins, and prostaglandin E2. These mediators cause vasodilatation and increased blood flow to the area (causing redness and heat).
2. Increased capillary permeability:
The vasoactive mediators also cause increased capillary permeability by causing endothelial cell contraction that widens the intercellular gaps of venules. This allows an outpouring of protein-rich fluid (exudate) into the extracellular tissues that results in a reduction of intravascular osmotic pressure and an increase in extravascular/interstitial pressure. The increased interstitial osmotic pressure leads to oedema.
3. Neutrophil migration:
Neutrophils leave the vasculature through the following sequence of events:
Margination and rolling: neutrophils flow nearer the vessel wall, rather than in the axial stream, which is referred to as margination. Following margination the neutrophils begin rolling along the surface of the vascular endothelium.
Activation and adhesion: then as a result of interaction with endothelial cell adhesion molecules (CAMs) that is mediated by selectins, the neutrophils are activated and adhere to the endothelium.
Transmigration: once bound to the endothelium, neutrophils squeeze through gaps between adjacent endothelial cells into the interstitial fluid, in a process calleddiapedesis. -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 32
Incorrect
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A 60-year-old man presents with marked breathlessness. He has with a history of ischaemic heart disease. On examination, there is coarse bibasal crackles, marked peripheral oedema and chest X-ray taken is consistent with severe pulmonary oedema. RR is 28 per minute.
Which receptor is responsible for detecting pulmonary oedema and the subsequent increase in respiratory rate?Your Answer:
Correct Answer: Juxtacapillary receptors
Explanation:Pulmonary oedema causes stimulation of the Juxtacapillary receptors (J receptors) leading to a reflex increase in breathing rate. These receptors are also thought to be involved in the sensation of dyspnoea. The J receptors are sensory cells and are located within the alveolar walls in juxtaposition to the pulmonary capillaries.
Aortic baroreceptor are involved in detecting blood pressure
Central chemoreceptors detect changes in CO2 and hydrogen ion within the brain
Atrial volume receptors regulate plasma volume
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 33
Incorrect
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A 19-year-old woman presents with dysuria and vaginal discharge. A swab was taken for culture. Culture results showed the presence of Neisseria gonorrhoeae infection. Treatment of azithromycin and doxycycline was started.
Which of the following statements is considered correct regarding Neisseria gonorrhoeae?Your Answer:
Correct Answer: Throat swabs can be used for diagnosis
Explanation:Neisseria gonorrhoeae is a Gram-negative diplococcus that causes gonorrhoea. Gonorrhoea is an acute pyogenic infection of nonciliated columnar and transitional epithelium; infection can be established at any site where these cells are found. Gonococcal infections are primarily acquired by sexual contact and occur primarily in the urethra, endocervix, anal canal, pharynx, and conjunctiva.
In men, acute urethritis, usually resulting in purulent discharge and dysuria (painful urination), is the most common manifestation. The endocervix is the most common site of infection in women. Symptoms of infection, when present, include dysuria, cervical discharge, and lower abdominal pain. Some cases in women may be asymptomatic leading to complications such as pelvic inflammatory disease. Blood-borne dissemination occurs in less than 1% of all infections, resulting in purulent arthritis and rarely septicaemia. Fever and a rash on the extremities can also be present. Other conditions associated with N. gonorrhoeae include anorectal and oropharyngeal infections. Infections in these sites are more common in men who have sex with men but can also occur in women.
Pharyngitis is the chief complaint in symptomatic oropharyngeal infections, whereas discharge, rectal pain, or bloody stools may be seen in rectal gonorrhoea. Approximately 30% to 60% of women with genital gonorrhoea have concurrent rectal infection. Newborns can acquire ophthalmia neonatorum, a gonococcal eye infection, during vaginal delivery through an infected birth canal.
Specimens collected for the recovery of N. gonorrhoeae may come from genital sources or from other sites, such as the rectum, pharynx, and joint
fluid. According to the 2010 STD Treatment guidelines, cephalosporins (e.g., ceftriaxone, cefixime) are currently recommended treatments. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 34
Incorrect
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The parasympathetic supply to the rectum is from which of the following:
Your Answer:
Correct Answer: Pelvic splanchnic nerves
Explanation:Parasympathetic supply is from the pelvic splanchnic nerves (S2 – S4) and inferior hypogastric plexus.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 35
Incorrect
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Which of the following statements is false regarding the biceps brachii muscle?
Your Answer:
Correct Answer: It pronates the radioulnar joint in the forearm
Explanation:The biceps brachii muscle is one of the chief muscles of the arm. The origin at the scapula and the insertion into the radius of the biceps brachii means it can act on both the shoulder joint and the elbow joint, which is why this muscle participates in a few movements of the arm. It derives its name from its two heads which merge in one unique distal body, defining the unusual structure of the muscle.
The biceps brachii muscle is supplied by the musculocutaneous nerve (C5-C6), a branch of the brachial plexus.
Arterial supply to the biceps brachii muscle varies considerably, coming from up to eight vessels originating from the brachial artery in the middle third of the arm.
In the shoulder joint both muscle heads partially enforce opposite movements. The long head pulls the arm away from the trunk (abduction) and turns it inwards (inward rotation) whereas the short head pulls the arm back towards the trunk (adduction). When both heads contract simultaneously it leads to an arm bend (flexion). In the elbow joint the muscle bends the forearm (flexion) and rotates it outwards (supination). The supination is most powerful in a flexed elbow. In addition to the movement functions, the biceps has the important task to support the humeral head within the shoulder joint. Its antagonist is the triceps brachii in the posterior compartment of the arm.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 36
Incorrect
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A 71-year-old woman presents with complaints of fatigue and worsening muscle weakness, and blood tests done shows a potassium level of 2.4 mmol/L.
Which is NOT a recognised cause of hypokalaemia?
Your Answer:
Correct Answer: Type 4 renal tubular acidosis
Explanation:A plasma potassium less than 3.5 mmol/L defines hypokalaemia.
Excessive liquorice ingestion causes hypermineralocorticoidism and leads to hypokalaemia.
Gitelman’s syndrome causes metabolic alkalosis with hypokalaemia and hypomagnesaemia. It is an inherited defect of the distal convoluted tubules.
Bartter’s syndrome causes hypokalaemic alkalosis. It is a rare inherited defect in the ascending limb of the loop of Henle.
Type 1 and 2 renal tubular acidosis both cause hypokalaemia
Type 4 renal tubular acidosis causes hyperkalaemia.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 37
Incorrect
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Which of the following is NOT typically associated with eosinophilia:
Your Answer:
Correct Answer: Whooping cough
Explanation:An eosinophil leucocytosis is defined as an increase in blood eosinophils above 0.4 x 109/L.It is most frequently due to:
Allergic diseases (e.g. bronchial asthma, hay fever, atopic dermatitis, urticaria)
Parasites (e.g. hookworm, ascariasis, tapeworm, schistosomiasis)
Skin diseases (e.g. psoriasis, pemphigus, urticaria, angioedema)
Drug sensitivity -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 38
Incorrect
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From which of the following cell types are platelets derived?
Your Answer:
Correct Answer: Megakaryocytes
Explanation:Synthesis of platelets occurs in the bone marrow by fragmentation of megakaryocytes cytoplasm, derived from the common myeloid progenitor cell. The average time for differentiation of the human stem cell to the production of platelets is about 10 days. The major regulator of platelet formation is thrombopoietin and 95% of this is produced by the liver. Normal platelet count is 150 – 450 x 109/L and the normal lifespan of a platelet is about 10 days. Usually about one-third of the marrow output of platelets may be trapped at any one time in the normal spleen.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 39
Incorrect
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A newborn baby is born by vaginal delivery to a mother who has a Chlamydia infection and who is started on treatment after the delivery. The neonate subsequently develops an infection also.
Which one of these is the most common neonatal manifestation of Chlamydia trachomatis infection?Your Answer:
Correct Answer: Conjunctivitis
Explanation:Conjunctivitis is the most common neonatal manifestation of Chlamydia trachomatis infection. The second commonest neonatal manifestation is pneumonia
Ophthalmia neonatorum refers to any conjunctivitis in the newborn period, irrespective of causative organism. Presently, chlamydia is the single most common cause, accounting for up to 40% of cases. Ophthalmia neonatorum caused by chlamydia typically presents 5 to 14 days after birth with unilateral or bilateral watery discharge that progressively becomes more copious and purulent. There is no associated risk of ulceration and perforation, and the eyes are less inflamed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 40
Incorrect
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How does abciximab mediate its antiplatelet effect:
Your Answer:
Correct Answer: It is a GPIIb/IIIa inhibitor.
Explanation:Abciximab, eptifibatide and tirofiban are GPIIb/IIIa inhibitors, inhibiting platelet aggregation by preventing the binding of fibrinogen, von Willebrand factor and other adhesive molecules.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 41
Incorrect
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Which statement concerning aerosol transmission is true?
Your Answer:
Correct Answer: They can be spread via ventilation systems in hospitals
Explanation:Aerosols are airborne particles less than 5 µm in size containing infective organisms.
They usually cause infection of both the upper and/or lower respiratory tract.
The organisms can remain suspended in the air for long periods and also survive outside the body.
They can be transmitted through the ventilation systems and can spread over great distances.
Some examples of organisms transmitted by the aerosol route include: Varicella zoster virus, Mycobacterium tuberculosis and measles virus
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 42
Incorrect
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Which of the following study designs is considered the most appropriate to safely determine whether an association exists between a well-established, commonly used, anti-hypertensive medication and causing type II diabetes mellitus?
Your Answer:
Correct Answer: A meta-analysis
Explanation:Evidence-based medicine may be defined as the systematic, quantitative, preferentially experimental approach to obtaining and using medical information. Therefore, meta-analysis, a statistical procedure that integrates the results of several independent studies, plays a central role in evidence-based medicine.
Meta-analysis is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 43
Incorrect
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Polyuria and polydipsia develop in a patient with a history of affective disorder, who has been on long-term lithium treatment. She has a fluid deprivation test done because she is suspected of having nephrogenic diabetic insipidus. Which of the following urine osmolality findings would be the most reliable in confirming the diagnosis?
Your Answer:
Correct Answer: After fluid deprivation <300 mosmol/kg, after IM desmopressin >800 mosmol/kg
Explanation:The inability to produce concentrated urine is a symptom of diabetes insipidus. Excessive thirst, polyuria, and polydipsia are all symptoms of this condition. There are two forms of diabetes insipidus: Nephrogenic diabetes insipidus and cranial (central) diabetes insipidus.
A lack of ADH causes cranial diabetic insipidus. Patients with cranial diabetes insipidus can have a urine output of up to 10-15 litres per 24 hours, however most patients can maintain normonatraemia with proper fluid consumption. Thirty percent of cases are idiopathic, while another thirty percent are caused by head injuries. Neurosurgery, brain tumours, meningitis, granulomatous disease (e.g. sarcoidosis), and medicines like naloxone and phenytoin are among the other reasons. There is also a very rare hereditary type that is linked to diabetes, optic atrophy, nerve deafness, and bladder atonia.
Renal resistance to the action of ADH causes nephrogenic diabetes insipidus. Urine output is significantly increased, as it is in cranial diabetes insipidus. Secondary polydipsia can keep serum sodium levels stable or raise them. Chronic renal dysfunction, metabolic diseases (e.g., hypercalcaemia and hypokalaemia), and medications, such as long-term lithium use and demeclocycline, are all causes of nephrogenic diabetes insipidus.
The best test to establish if a patient has diabetes insipidus vs another cause of polydipsia is the water deprivation test, commonly known as the fluid deprivation test. It also aids in the distinction between cranial and nephrogenic diabetes insipidus. Weight, urine volume, urine osmolality, and serum osmolality are all measured after patients are denied water for up to 8 hours. At the end of the 8-hour period, 2 micrograms of IM desmopressin is given, and measures are taken again at 16 hours.
The following are the way results are interpreted:
Urine osmolality after fluid deprivation : Urine osmolality after IM desmopressin
Cranial diabetes insipidus: <300 mosmol/kg : >800 mosmol/kg
Nephrogenic diabetes insipidus: <300 mosmol/kg : <300 mosmol/kg
Primary polydipsia: >800 mosmol/kg : >800 mosmol/kg -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 44
Incorrect
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Regarding relationships between two variables, what does a negative correlation coefficient indicate:
Your Answer:
Correct Answer: The two variables are inversely related
Explanation:A negative correlation coefficient means that the two variables are inversely related e.g. socio-economic class and mortality.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 45
Incorrect
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What is the pathophysiology of Cushing's syndrome:
Your Answer:
Correct Answer: Glucocorticoid excess
Explanation:Cushing’s syndrome is the name given to the clinical symptoms and signs induced by chronic glucocorticoid excess.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 46
Incorrect
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You review a 37-year-old man with a history of intravenous drug abuse who admits to sharing needles in the past. He has a flu-like illness and a rash. Concerned he may be experiencing an HIV seroconversion illness, you order a test.
Which of these tests is most reliably used to diagnose HIV at this stage?
Your Answer:
Correct Answer: p24 antigen test
Explanation:Serum concentrations of the p24 antigen are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection. P24 is the viral protein that makes up most of the core of the HIV.
ELISA and other antibody tests, though a very sensitive way of detecting the presence of HIV, cannot be used in the early stages of the disease. This is because of the window period of 6-12 weeks before antibodies are produced. These tests will be negative during a seroconversion illness.
The ‘rapid HIV test’ is an HIV antibody test. It will also be negative during the ‘window period’ since it takes time for antibodies to be produced. It is called the ‘rapid test’ as it can detect antibodies in blood or saliva much quicker than the other antibody tests and results are often back within 20 minutes.
CD4 and CD8 counts are usually normal in the early stages of the HIV infection and cannot be used in this case.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 47
Incorrect
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Regarding bile acids, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The main primary bile acids are deoxycholic acid and lithocholic acid.
Explanation:Bile acids have a hydrophobic and a hydrophilic end and in aqueous solution, bile salts orient themselves around droplets of lipid forming micelles to keep the lipid droplets dispersed. The principal primary bile acids are cholic acid and chenodeoxycholic acid. They are made more soluble by conjugation with taurine or glycine in the liver. Of the bile acids excreted into the intestine, about 95% are reabsorbed into the portal circulation by active transport mechanisms in the distal ileum and recycled by the liver.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 48
Incorrect
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You are taking care of a 55-year-old male patient who is a weightlifter. He is suspected of having a direct inguinal hernia. Where would this hernia appear?
Your Answer:
Correct Answer: Medial to the inferior epigastric artery
Explanation:A direct inguinal hernia is a form of groin hernia that occurs when abdominal viscera protrude through a weakness in the posterior wall of the inguinal canal, notably through Hesselbach’s triangle, medial to the inferior epigastric veins.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 49
Incorrect
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Regarding NSAIDs, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Diclofenac is contraindicated in people with ischaemic heart disease.
Explanation:Due to their increased risk of cardiovascular adverse events, coxibs and diclofenac are contraindicated in people with ischaemic heart disease, cerebrovascular disease, peripheral arterial disease and mild, moderate, or severe heart failure. Other NSAIDs are only contraindicated in people with severe heart failure. Selective inhibition of COX-2 is associated with less gastrointestinal intolerance. In single doses NSAIDs have analgesic activity comparable to that of paracetamol, therefore given their side effect profile, paracetamol is preferred, particularly in the elderly. Pain relief starts soon after taking the first dose and a full analgesic effect should normally be obtained within a week, whereas an anti-inflammatory effect may not be achieved (or may not be clinically assessable) for up to 3 weeks. Mefenamic acid has only very mild anti-inflammatory properties.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 50
Incorrect
SESSION STATS - PERFORMANCE PER SPECIALTY
