Immunisation: hypotonic hyporesponsive episode: 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 · Immunisation: hypotonic hyporesponsive episode

Sample item

Eight hours after her first whole-cell pertussis-containing injection, an infant becomes pale, limp and unresponsive but keeps breathing normally with no rash or stridor. She recovers fully within a few hours. How is this event best described?

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

The answer and the reasoning

A. Hypotonic-hyporesponsive episode

A hypotonic-hyporesponsive episode occurs within hours of a pertussis-containing vaccine and resolves spontaneously. Anaphylaxis would show urticaria, stridor, wheeze or hypotension within minutes. Encephalopathy shows seizures or prolonged altered consciousness for more than a day.

Option by option

  • A. Hypotonic-hyporesponsive episode (correct)

    Correct. Sudden pallor and limpness with spontaneous full recovery fits this self-limited reaction.

  • B. Pertussis vaccine encephalopathy

    Encephalopathy causes seizures or altered consciousness lasting a day or more.

  • C. Anaphylaxis

    Anaphylaxis presents early with airway or circulatory compromise and skin signs, which are absent here.

  • D. Breath-holding spell

    Breath-holding spells follow crying in older infants and toddlers and are not triggered by vaccines.

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 A, Hypotonic-hyporesponsive episode. A hypotonic-hyporesponsive episode occurs within hours of a pertussis-containing vaccine and resolves spontaneously.

Why is "Pertussis vaccine encephalopathy" not the answer?

Encephalopathy causes seizures or altered consciousness lasting a day or more.

Why is "Anaphylaxis" not the answer?

Anaphylaxis presents early with airway or circulatory compromise and skin signs, which are absent here.

Why is "Breath-holding spell" not the answer?

Breath-holding spells follow crying in older infants and toddlers and are not triggered by vaccines.

What concept does this question test?

It tests Immunisation: hypotonic hyporesponsive episode in Pediatrics. Anaphylaxis would show urticaria, stridor, wheeze or hypotension within minutes. Encephalopathy shows seizures or prolonged altered consciousness for more than a day.

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 Immunisation: hypotonic hyporesponsive episode?

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.