📝 Step 6 — KMU Past Papers & Exam Learning

This section contains KMU-style past paper questions designed to strengthen conceptual understanding. Focus on understanding explanations rather than memorizing answers.

🎯 How to Study KMU Past Papers

• Read the question carefully.
• Think about the answer before looking.
• Read the explanation slowly.
• Understand the reasoning behind the correct answer.
• Revise difficult questions again.

MCQ 1

Question:

A child with acute watery diarrhoea develops tachycardia and delayed capillary refill. Which physiological disturbance is primarily responsible for these findings?

Options:

Increased plasma oncotic pressure
Reduced circulating blood volume
Excess intracellular potassium
Increased bicarbonate retention
Reduced sympathetic activity

Correct Answer:
Reduced circulating blood volume

Explanation:
Severe diarrhoea causes extracellular fluid loss leading to hypovolemia, which produces tachycardia and poor peripheral perfusion.

MCQ 2

Question:

Loperamide decreases stool frequency mainly through its action on:

Options:

Gastric parietal cells
Intestinal opioid receptors
Pancreatic acinar cells
Colonic chloride channels
Mesenteric blood vessels

Correct Answer:
Intestinal opioid receptors

Explanation:
Loperamide activates μ-opioid receptors in the intestinal wall, reducing propulsive peristalsis and increasing water absorption time.

MCQ 3

Question:

A patient with severe cholera loses large amounts of bicarbonate-rich fluid in stool. Which acid-base disturbance is most likely to occur?

Options:

Respiratory acidosis
Metabolic alkalosis
Respiratory alkalosis
Metabolic acidosis
Mixed alkalosis

Correct Answer:
Metabolic acidosis

Explanation:
Loss of bicarbonate in diarrhoeal stool leads to metabolic acidosis due to reduced buffering capacity.

MCQ 4

Question:

Which mechanism best explains the effectiveness of oral rehydration solution in acute gastroenteritis?

Options:

Inhibition of intestinal chloride secretion
Activation of sodium-glucose co-transport
Suppression of enteric nervous activity
Neutralization of bacterial toxins
Reduction of mucosal inflammation

Correct Answer:
Activation of sodium-glucose co-transport

Explanation:
Glucose enhances sodium absorption through SGLT transporters, and water follows osmotically.

MCQ 5

Question:

A child presents with profuse watery diarrhoea but no blood or leukocytes in stool. Which pathogenic mechanism is most likely involved?

Options:

Mucosal ulceration
Toxin-mediated hypersecretion
Autoimmune villous destruction
Mechanical intestinal obstruction
Ischemic bowel injury

Correct Answer:
Toxin-mediated hypersecretion

Explanation:
Secretory diarrhoea commonly occurs due to enterotoxins stimulating chloride and water secretion without mucosal invasion.

MCQ 6

Question:

A patient taking stimulant laxatives for several months develops worsening constipation when the medication is stopped. Which mechanism best explains this condition?

Options:

Increased intestinal fibrosis
Loss of enteric nerve responsiveness
Excess bile acid secretion
Reduced gastric emptying
Impaired pancreatic secretion

Correct Answer:
Loss of enteric nerve responsiveness

Explanation:
Chronic stimulant laxative use may lead to dependence due to reduced normal enteric nervous activity.

MCQ 7

Question:

In acute gastroenteritis, reduced skin turgor primarily reflects:

Options:

Loss of intracellular proteins
Reduced interstitial fluid volume
Increased capillary permeability
Elevated plasma sodium concentration
Failure of lymphatic drainage

Correct Answer:
Reduced interstitial fluid volume

Explanation:
Dehydration decreases interstitial fluid, causing poor skin elasticity and reduced skin turgor.

MCQ 8

Question:

Which intervention most effectively interrupts transmission of food-borne infections at community level?

Options:

Mass vitamin supplementation
Routine antimicrobial prophylaxis
Improved sewage disposal
Restriction of dairy products
Increased dietary fiber intake

Correct Answer:
Improved sewage disposal

Explanation:
Safe sanitation reduces fecal contamination of food and water, interrupting fecal-oral spread.

MCQ 9

Question:

A patient with constipation is prescribed psyllium. The therapeutic effect depends mainly on:

Options:

Reduced intestinal secretion
Enhanced stool water retention
Direct smooth muscle relaxation
Inhibition of chloride transport
Suppression of enteric reflexes

Correct Answer:
Enhanced stool water retention

Explanation:
Bulk-forming agents absorb water, increasing stool mass and stimulating bowel movement.

MCQ 10

Question:

Which electrolyte abnormality is most likely in prolonged diarrhoeal illness with excessive stool losses?

Options:

Hypercalcemia
Hypermagnesemia
Hypokalemia
Hyperphosphatemia
Hypouricemia

Correct Answer:
Hypokalemia

Explanation:
Potassium is lost in stool during prolonged diarrhoea, predisposing to muscle weakness and arrhythmias.

MCQ 11

Question:

A child with acute gastroenteritis becomes lethargic and develops sunken eyes. These findings are primarily due to:

Options:

Reduced cerebrospinal fluid production
Intravascular fluid depletion
Increased intracranial pressure
Excess extracellular calcium
Impaired hepatic metabolism

Correct Answer:
Intravascular fluid depletion

Explanation:
Severe dehydration decreases plasma volume, leading to reduced tissue perfusion and lethargy.

MCQ 12

Question:

Which feature best distinguishes osmotic diarrhoea from secretory diarrhoea?

Options:

Persistence despite fasting
Association with enterotoxins
Reduction after fasting
Marked inflammatory infiltrate
Presence of visible blood

Correct Answer:
Reduction after fasting

Explanation:
Osmotic diarrhoea improves during fasting because unabsorbed osmotic substances are removed.

MCQ 13

Question:

A patient develops constipation after prolonged dehydration. Which physiological process contributes most directly to stool hardening?

Options:

Reduced bile salt production
Excess colonic water absorption
Enhanced gastric acid secretion
Increased intestinal mucus loss
Accelerated small bowel transit

Correct Answer:
Excess colonic water absorption

Explanation:
Slow transit allows greater water absorption from stool, producing hard feces.

MCQ 14

Question:

Which complication is most likely if anti-motility drugs are used in invasive bacterial diarrhoea?

Options:

Enhanced nutrient absorption
Delayed toxin clearance
Accelerated mucosal repair
Reduced bacterial adhesion
Improved electrolyte retention

Correct Answer:
Delayed toxin clearance

Explanation:
Reduced bowel motility may retain invasive organisms and toxins within the intestine.

MCQ 15

Question:

Rotavirus commonly causes diarrhoea in children by damaging:

Options:

Enterocytes of intestinal villi
Submucosal arterial supply
Gastric smooth muscle
Pancreatic endocrine cells
Mesenteric lymphatics

Correct Answer:
Enterocytes of intestinal villi

Explanation:
Rotavirus injures absorptive villous cells, causing malabsorption and watery diarrhoea.

MCQ 16

Question:

Which physiological response helps maintain blood pressure during moderate dehydration?

Options:

Reduced sympathetic discharge
Peripheral vasoconstriction
Decreased heart rate
Enhanced sodium excretion
Reduced renin release

Correct Answer:
Peripheral vasoconstriction

Explanation:
Hypovolemia activates sympathetic pathways causing vasoconstriction to preserve perfusion.

MCQ 17

Question:

A patient receiving lactulose for constipation experiences softer stools mainly because the drug:

Options:

Stimulates opioid receptors
Increases luminal osmotic pressure
Suppresses intestinal secretion
Enhances gastric motility
Blocks sodium absorption

Correct Answer:
Increases luminal osmotic pressure

Explanation:
Lactulose retains water within the bowel lumen through osmotic action.

MCQ 18

Question:

Which factor most strongly contributes to the high incidence of gastroenteritis in children?

Options:

Reduced bile formation
Immature immune defenses
Increased gastric acidity
Enhanced mucosal thickness
Reduced intestinal transit

Correct Answer:
Immature immune defenses

Explanation:
Children have less developed immunity and smaller fluid reserves, increasing susceptibility.

MCQ 19

Question:

A patient with severe diarrhoea develops muscle weakness and cardiac irritability. Which mechanism best explains these findings?

Options:

Excess plasma chloride
Reduced serum potassium
Increased serum bicarbonate
Excess intracellular sodium
Reduced calcium excretion

Correct Answer:
Reduced serum potassium

Explanation:
Potassium depletion from gastrointestinal losses affects neuromuscular and cardiac function.

MCQ 20

Question:

The most important immediate objective in management of acute gastroenteritis is to:

Options:

Suppress intestinal flora
Reduce stool frequency
Correct fluid deficit
Stop intestinal motility
Prevent gastric secretion

Correct Answer:
Correct fluid deficit

Explanation:
The major life-threatening complication is dehydration, making fluid replacement the first priorit

📌 Important Exam Strategy

KMU examinations often test integrated understanding rather than isolated facts. Focus on linking anatomy, embryology, histology, and clinical concepts when reviewing questions.

✅ Revision Tip

If you can explain the reason behind the correct answer without looking at notes, your concept is strong.