Neurology: neuroleptic malignant syndrome versus serotonin syndrome: practice question

A General Medicine 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 Medicine · Neurology: neuroleptic malignant syndrome versus serotonin syndrome

Sample item

Two patients have fever, rigidity and altered sensorium: one after starting haloperidol, the other after adding tramadol to sertraline. Which feature best identifies the haloperidol patient's syndrome?

AProfuse diarrhoea with agitation and tremorBMarked hyperreflexia with dilated pupils and flushingCOnset within hours with inducible ocular or ankle clonusDGradual onset with lead-pipe rigidity and slow reflexes

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

The answer and the reasoning

D. Gradual onset with lead-pipe rigidity and slow reflexes

Neuroleptic malignant syndrome evolves over days after dopamine blockade, with severe lead-pipe rigidity, bradyreflexia and a high creatine kinase. Serotonin syndrome comes on within hours with clonus, hyperreflexia, mydriasis, diarrhoea and tremor.

Option by option

A. Profuse diarrhoea with agitation and tremor
Diarrhoea and tremor are features of serotonin toxicity.
B. Marked hyperreflexia with dilated pupils and flushing
Hyperreflexia with dilated pupils is typical of serotonin toxicity.
C. Onset within hours with inducible ocular or ankle clonus
Rapid onset with clonus is typical of serotonin toxicity.
D. Gradual onset with lead-pipe rigidity and slow reflexes (correct)
Correct. A days-long course with lead-pipe rigidity and slow reflexes is typical of NMS.

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 Medicine question

What is the answer to this General Medicine question?

The best answer is D, Gradual onset with lead-pipe rigidity and slow reflexes. Neuroleptic malignant syndrome evolves over days after dopamine blockade, with severe lead-pipe rigidity, bradyreflexia and a high creatine kinase.

Why is "Profuse diarrhoea with agitation and tremor" not the answer?

Diarrhoea and tremor are features of serotonin toxicity.

Why is "Marked hyperreflexia with dilated pupils and flushing" not the answer?

Hyperreflexia with dilated pupils is typical of serotonin toxicity.

Why is "Onset within hours with inducible ocular or ankle clonus" not the answer?

Rapid onset with clonus is typical of serotonin toxicity.

What concept does this question test?

It tests Neurology: neuroleptic malignant syndrome versus serotonin syndrome in General Medicine. Serotonin syndrome comes on within hours with clonus, hyperreflexia, mydriasis, diarrhoea and tremor.

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 Neurology: neuroleptic malignant syndrome versus serotonin syndrome?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.