Fluids and Transfusion — Practice Questions

Pharmacology — Fluids, Electrolytes and Transfusion, NMC MBBS licence examination syllabus (Nepal Medical Council).

Fluids and transfusion — NMC-style practice questions

Practice questions written for this chapter. These are not past NMC papers.

📋 About these questions: These are practice questions written to test the reasoning in this chapter. They are NOT reproduced from any past Nepal Medical Council examination, and no verified past NMC questions were supplied for this chapter. All volumes, rates and thresholds come from local protocol.

Level 1–2 — recall and understanding

Q1. Why is 5% dextrose unsuitable for resuscitating a shocked patient? A. It causes hyperglycaemia B. Once the glucose is metabolised it becomes FREE WATER and distributes through all compartments C. It is too viscous D. It causes haemolysis ANSWER: B. Why: only a small fraction remains in the circulation, so it does not restore circulating volume — and the free water load lowers the serum sodium. LEARNING POINT: use a balanced crystalloid or saline for resuscitation, and match the fluid to the loss.

Q2. The earliest characteristic ECG change in hyperkalaemia is: A. TALL TENTED T WAVES B. ST elevation C. Prolonged QT D. Delta waves ANSWER: A. Why: the progression runs tall tented T waves → flattened P waves → widened QRS → sine wave pattern → arrest. LEARNING POINT: management is protect the myocardium, shift potassium into cells, then remove it from the body.

Level 3–4 — application and clinical reasoning

Q3. A patient's hypokalaemia will not correct despite repeated potassium replacement. The most useful next test is: A. Serum MAGNESIUM B. Serum calcium C. Thyroid function D. Repeat potassium only ANSWER: A — magnesium. Why: magnesium depletion causes renal potassium wasting, so replacement is lost as fast as it is given. The potassium will not stay up until magnesium is corrected. LEARNING POINT: hypokalaemia also potentiates digoxin.

Q4. A woman with chronic hyponatraemia is corrected rapidly overnight, improves, then days later develops weakness, dysarthria and reduced consciousness. The cause is: A. Recurrent hyponatraemia B. OSMOTIC DEMYELINATION from over-rapid correction C. Stroke D. Sedation ANSWER: B. Why: the brain adapts to chronic hyponatraemia. Rapid correction reverses the osmotic gradient faster than the brain can readjust, causing demyelination that appears days later. LEARNING POINT: this is preventable, not treatable — correct slowly within protocol limits.

Q5. Ten minutes into a transfusion a patient develops fever, rigors, back pain, dark urine and hypotension. You should: A. Slow the infusion and give paracetamol B. STOP the transfusion immediately, keep the line, resuscitate and inform the blood bank C. Continue and observe D. Give an antihistamine and continue ANSWER: B. Why: this is an acute haemolytic reaction, most often ABO incompatibility from an identification failure. Every further millilitre worsens it. LEARNING POINT: recheck the identity of patient and unit, and monitor for acute kidney injury and coagulopathy.

Level 5 — exception-based

Q6. The commonest cause of a FATAL ABO-incompatible transfusion is: A. A laboratory cross-matching error B. A CLERICAL error — wrong sample, wrong label or wrong patient at the bedside C. An undetected antibody D. Blood stored too long ANSWER: B. Why: most fatal ABO reactions are identification failures rather than laboratory failures, which is why the bedside identity check is the last line of defence. LEARNING POINT: check identity at the bedside against the unit and compatibility label, never at the desk.

Q7. Why does large-volume normal saline cause a metabolic acidosis? A. It contains lactate B. Its CHLORIDE content is considerably higher than plasma, producing hyperchloraemic acidosis C. It is hypotonic D. It contains potassium ANSWER: B. Why: the chloride load displaces bicarbonate. Balanced solutions are closer to plasma composition and avoid it. LEARNING POINT: the resulting acidosis can be misread as worsening illness — see the acid-base chapter.

Syllabus points

Recall and understanding questions
Application and clinical reasoning questions
Exception-based questions

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