Perioperative care: prolonged apnoea after suxamethonium: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Perioperative care: prolonged apnoea after suxamethonium

Sample item

A patient remains paralysed and apnoeic for three hours after a single dose of suxamethonium at induction. There is no history of muscle disease. What is the likely cause and management?

APlasma cholinesterase deficiency, with sedation and ventilation until recoveryBMalignant hyperthermia, treated with dantroleneCMyasthenia gravis, treated with neostigmineDResidual volatile agent, treated by flumazenil

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Plasma cholinesterase deficiency, with sedation and ventilation until recovery

Suxamethonium is broken down by plasma cholinesterase, and in the atypical enzyme or low levels, paralysis lasts for hours. The patient is kept sedated and ventilated until the block wears off. Reversal agents are not effective, since the block is a depolarising one.

Option by option

A. Plasma cholinesterase deficiency, with sedation and ventilation until recovery (correct)
Correct. Deficiency or abnormality of plasma cholinesterase prolongs suxamethonium paralysis, and care is supportive until recovery.
B. Malignant hyperthermia, treated with dantrolene
Malignant hyperthermia produces rigidity, hypercarbia and fever rather than flaccid prolonged paralysis.
C. Myasthenia gravis, treated with neostigmine
Myasthenia gravis makes patients resistant to suxamethonium and is not treated with neostigmine in this setting.
D. Residual volatile agent, treated by flumazenil
Flumazenil reverses benzodiazepines and volatile agents do not cause prolonged complete paralysis.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is A, Plasma cholinesterase deficiency, with sedation and ventilation until recovery. Suxamethonium is broken down by plasma cholinesterase, and in the atypical enzyme or low levels, paralysis lasts for hours.

Why is "Malignant hyperthermia, treated with dantrolene" not the answer?

Malignant hyperthermia produces rigidity, hypercarbia and fever rather than flaccid prolonged paralysis.

Why is "Myasthenia gravis, treated with neostigmine" not the answer?

Myasthenia gravis makes patients resistant to suxamethonium and is not treated with neostigmine in this setting.

Why is "Residual volatile agent, treated by flumazenil" not the answer?

Flumazenil reverses benzodiazepines and volatile agents do not cause prolonged complete paralysis.

What concept does this question test?

It tests Perioperative care: prolonged apnoea after suxamethonium in General Surgery. The patient is kept sedated and ventilated until the block wears off. Reversal agents are not effective, since the block is a depolarising one.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Perioperative care: prolonged apnoea after suxamethonium?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.