Infectious diseases: diphtheria: 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 · Infectious diseases: diphtheria

Sample item

A 6-year-old unimmunised child has fever, sore throat and a swollen neck. The tonsils are covered by a grey, adherent membrane that bleeds on scraping and extends to the uvula. What is the most important immediate management?

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

The answer and the reasoning

A. Equine diphtheria antitoxin after a sensitivity test, with penicillin or erythromycin

The adherent grey pseudomembrane with bull neck suggests diphtheria, in which exotoxin causes myocarditis and neuropathy. Antitoxin neutralises only circulating toxin, so it is given early on clinical suspicion with antibiotics to eradicate the organism, and isolation and airway monitoring are needed. Contacts receive prophylaxis and immunisation.

Option by option

  • A. Equine diphtheria antitoxin after a sensitivity test, with penicillin or erythromycin (correct)

    Early antitoxin limits toxin-mediated damage and antibiotics clear the bacillus.

  • B. Oral amoxicillin and review in 48 hours

    Amoxicillin alone without antitoxin does not neutralise the toxin.

  • C. Intravenous dexamethasone alone

    Corticosteroids do not neutralise toxin and are not definitive therapy.

  • D. Wait for the throat swab culture before treatment

    Delay for culture allows toxin to bind tissue, and treatment depends on clinical suspicion.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is A, Equine diphtheria antitoxin after a sensitivity test, with penicillin or erythromycin. The adherent grey pseudomembrane with bull neck suggests diphtheria, in which exotoxin causes myocarditis and neuropathy.

Why is "Oral amoxicillin and review in 48 hours" not the answer?

Amoxicillin alone without antitoxin does not neutralise the toxin.

Why is "Intravenous dexamethasone alone" not the answer?

Corticosteroids do not neutralise toxin and are not definitive therapy.

Why is "Wait for the throat swab culture before treatment" not the answer?

Delay for culture allows toxin to bind tissue, and treatment depends on clinical suspicion.

What concept does this question test?

It tests Infectious diseases: diphtheria in General Medicine. Antitoxin neutralises only circulating toxin, so it is given early on clinical suspicion with antibiotics to eradicate the organism, and isolation and airway monitoring are needed. Contacts receive prophylaxis and immunisation.

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 Infectious diseases: diphtheria?

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.