STI: monitoring response to syphilis treatment: practice question

A Dermatology 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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Dermatology · STI: monitoring response to syphilis treatment

Sample item

A patient treated for early syphilis returns at 6 months. Which finding indicates an adequate serological response?

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

The answer and the reasoning

B. A fourfold or greater fall in the RPR or VDRL titre

Non-treponemal titres are used to follow therapy, and a fourfold fall (two dilutions) within 6 to 12 months indicates a good response. Treponemal tests usually remain reactive for life and are not used to monitor treatment. A fourfold rise suggests relapse or reinfection.

Option by option

  • A. Disappearance of the TPHA reactivity

    TPHA stays reactive after treatment, so loss of reactivity is not expected.

  • B. A fourfold or greater fall in the RPR or VDRL titre (correct)

    Correct. A fourfold fall in titre indicates response.

  • C. A rise in the VDRL titre by one dilution

    A one-dilution change is within test variation.

  • D. A persistently reactive treponemal test turning negative

    Treponemal tests remain positive in most patients for life.

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 Dermatology question

What is the answer to this Dermatology question?

The best answer is B, A fourfold or greater fall in the RPR or VDRL titre. Non-treponemal titres are used to follow therapy, and a fourfold fall (two dilutions) within 6 to 12 months indicates a good response.

Why is "Disappearance of the TPHA reactivity" not the answer?

TPHA stays reactive after treatment, so loss of reactivity is not expected.

Why is "A rise in the VDRL titre by one dilution" not the answer?

A one-dilution change is within test variation.

Why is "A persistently reactive treponemal test turning negative" not the answer?

Treponemal tests remain positive in most patients for life.

What concept does this question test?

It tests STI: monitoring response to syphilis treatment in Dermatology. Treponemal tests usually remain reactive for life and are not used to monitor treatment. A fourfold rise suggests relapse or reinfection.

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 STI: monitoring response to syphilis treatment?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.