Final MB MCQ / EMQ Course in Medicine

All candidates will receive extensive written answers and notes covering both the pre-course material and the further paper covered on the day. Below is a sample of a typical MCQ question and answer. An EMQ question and the answer can be found here.

MCQ Sample Questions

Question

Concerning heart failure:

  1. primary valvular disease is the most common cause.
  2. raised levels of atrial natriuretic peptide are thought to be beneficial in heart failure.
  3. a 3rd heart sound is a common finding on examination.
  4. the heart looks small on plain antero-posterior chest radiograph.
  5. all diuretics cause hypokalaemia.

The causes of heart disease are generally thought to be divided as follows, with valvular disease only causing 7% of cases of heart failure:

Included in the 'other' category are cardiomyopathy, alcohol-induced heart failure, previously unrecognised hypertension and silent ischaemia.

Cells of the atria of the heart store and release the 28-amino-acid atrial natriuretic peptide (ANP) in response to stretch of the right atrium by increased central venous pressure. The relative volume overload of the atria that occurs in heart failure causes levels of ANP to be high, leading to a variety of beneficial effects in heart failure, including:

When it was first discovered, ANP was cast as the cardiovascular hero in heart failure, standing opposed to the villainous intents of vasoconstrictors like angiotensin, ADH and endothelin in heart failure. Unfortunately, its potential therapeutic use foundered with the discovery of its short plasma half-life. Subsequent attempts to devise ANP-agonists or agents to block clearance of the endogenous peptide have been unsuccessful.

The third heart sound (S3) occurs in early diastole due to rapid ventricular filling as soon as the mitral and tricuspid valves open. It can be normal in children and young adults, but is abnormal in others and represents heart failure or volume overload of the heart (e.g. mitral or aortic regurgitation). It is commonly referred to as a 'distressed' sound.

The fourth heart sound (S4) occurs in late diastole in association with ventricular filling due to atrial systole, and is related to reduced ventricular compliance. It is a low frequency oscillation that can be normal at older ages owing to a physiological decline in ventricular compliance, but is nearly always abnormal at younger ages especially if it is of high intensity or is palpable. It is common in ventricular hypertrophy, particularly with hypertension and aortic stenosis, and is almost invariable in acute myocardial infarction. S4 may arise from the right ventricle, the left ventricle or both. It is commonly referred to as a 'stressed' sound.

The chest X-ray in a patient with heart failure has a classical pattern (see diagram below), comprising:

  1. Cardiomegaly (greater than the width of one hemithorax)
  2. Upper lobe venous diversion
  3. Kerley-B lines (fine peripheral septal lines; named after Peter J Kerley, an English radiologist who also described Kerley-A and Kerley-C lines on chest radiographs)
  4. Bat's wing hilar oedema
  5. Bilateral effusions

Diuretics commonly used in the treatment of heart failure include:

  1. Thiazide diuretics (e.g. bendrofluazide, metolazone): decrease active reabsorption of Na+ and Cl- in the distal convoluted tubule by binding to the chloride site of the electroneutral Na+/Cl- co-transport system and inhibiting its action. Potassium loss with these drugs is significant and can be serious. Excretion of uric acid (gout) and calcium is decreased, whereas that of magnesium is increased.
  2. Loop diuretics (e.g. furosemide/frusemide, bumetanide): inhibit transport of NaCl out of the lumen of the thick segment of the ascending limb of the loop of Henle. These are the most powerful of all diuretics, potentially causing loss of up to 25% of the Na+ in the filtrate by direct inhibition of the Na+/K+/2Cl- carrier in the luminal membrane. Again, these drugs cause significant K+ loss. There is an increase in the excretion of calcium and magnesium, and a decrease in the excretion of uric acid (gout).
  3. Potassium-sparing diuretics (e.g. spironolactone, amiloride): Spironolactone has a limited diuretic action. By acting as an aldosterone antagonist it inhibits Na+ retention and decreases K+ excretion. Similarly, amiloride has limited diuretic efficacy. By blocking Na+ reabsorption in the collecting tubules and ducts, it concomitantly decreases K+ excretion. Importantly, drugs in this class are the only diuretics that DO NOT CAUSE HYPERKALAEMIA.