Paediatric infections: infantile botulism: practice question

A Pediatrics 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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Pediatrics · Paediatric infections: infantile botulism

Sample item

A 5-month-old has constipation, a weak cry, poor sucking, ptosis, dilated sluggish pupils and descending symmetric weakness over several days. What is the mechanism of the toxin responsible?

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

The answer and the reasoning

B. Cleaves SNARE proteins and blocks acetylcholine release at the nerve terminal

Infantile botulism results from ingestion of Clostridium botulinum spores, which germinate in the infant gut and release toxin. The toxin cleaves SNARE proteins and prevents presynaptic acetylcholine release, giving a descending flaccid paralysis with constipation. Honey is a recognised source, and human botulism immune globulin is used for treatment.

Option by option

  • A. Blocks postsynaptic nicotinic receptors

    Postsynaptic receptor blockade describes curare and similar agents.

  • B. Cleaves SNARE proteins and blocks acetylcholine release at the nerve terminal (correct)

    Correct. Botulinum toxin blocks acetylcholine release presynaptically.

  • C. Inhibits acetylcholinesterase in the synapse

    Cholinesterase inhibition would produce excess cholinergic stimulation, not paralysis.

  • D. Blocks glycine and GABA release in the spinal cord

    Blocking inhibitory neurotransmitter release is the action of tetanus toxin, which causes spastic rigidity.

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.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is B, Cleaves SNARE proteins and blocks acetylcholine release at the nerve terminal. Infantile botulism results from ingestion of Clostridium botulinum spores, which germinate in the infant gut and release toxin.

Why is "Blocks postsynaptic nicotinic receptors" not the answer?

Postsynaptic receptor blockade describes curare and similar agents.

Why is "Inhibits acetylcholinesterase in the synapse" not the answer?

Cholinesterase inhibition would produce excess cholinergic stimulation, not paralysis.

Why is "Blocks glycine and GABA release in the spinal cord" not the answer?

Blocking inhibitory neurotransmitter release is the action of tetanus toxin, which causes spastic rigidity.

What concept does this question test?

It tests Paediatric infections: infantile botulism in Pediatrics. The toxin cleaves SNARE proteins and prevents presynaptic acetylcholine release, giving a descending flaccid paralysis with constipation. Honey is a recognised source, and human botulism immune globulin is used for treatment.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Paediatric infections: infantile botulism?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.