Communicable diseases: diphtheria management: practice question

A PSM 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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PSM · Communicable diseases: diphtheria management

Sample item

A 6-year-old unimmunised boy has fever, a sore throat, a grey adherent membrane over the tonsils and a swollen neck. A throat swab has been sent. What is the most appropriate next step?

AGive corticosteroids alone to reduce the membraneBGive diphtheria antitoxin after a test dose, with an antibiotic, without waiting for cultureCGive penicillin alone and review in 48 hoursDWait for the culture result before giving any treatment

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

The answer and the reasoning

B. Give diphtheria antitoxin after a test dose, with an antibiotic, without waiting for culture

Diphtheria is diagnosed clinically and antitoxin must be given early, as it neutralises only circulating toxin and not toxin already bound to tissues. Sensitivity testing for horse serum is done first, and penicillin or erythromycin is added to eradicate the organism and reduce spread. Contacts are examined and given prophylaxis and booster vaccination.

Option by option

A. Give corticosteroids alone to reduce the membrane
Steroids do not remove the membrane or neutralise the toxin and are not the treatment.
B. Give diphtheria antitoxin after a test dose, with an antibiotic, without waiting for culture (correct)
Correct. Early antitoxin plus an antibiotic is the standard emergency treatment.
C. Give penicillin alone and review in 48 hours
An antibiotic alone does not neutralise the toxin that causes the complications.
D. Wait for the culture result before giving any treatment
Delay until culture allows toxin to bind and raises the risk of myocarditis and death.

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 PSM question

What is the answer to this PSM question?

The best answer is B, Give diphtheria antitoxin after a test dose, with an antibiotic, without waiting for culture. Diphtheria is diagnosed clinically and antitoxin must be given early, as it neutralises only circulating toxin and not toxin already bound to tissues.

Why is "Give corticosteroids alone to reduce the membrane" not the answer?

Steroids do not remove the membrane or neutralise the toxin and are not the treatment.

Why is "Give penicillin alone and review in 48 hours" not the answer?

An antibiotic alone does not neutralise the toxin that causes the complications.

Why is "Wait for the culture result before giving any treatment" not the answer?

Delay until culture allows toxin to bind and raises the risk of myocarditis and death.

What concept does this question test?

It tests Communicable diseases: diphtheria management in PSM. Sensitivity testing for horse serum is done first, and penicillin or erythromycin is added to eradicate the organism and reduce spread. Contacts are examined and given prophylaxis and booster vaccination.

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 Communicable diseases: diphtheria management?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.