Virology: herpesviruses: practice question

A Microbiology 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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Microbiology · Virology: herpesviruses

Sample item

A 35-year-old man has fever, headache, altered behaviour and a focal seizure. MRI shows hyperintensity in the left temporal lobe. CSF shows lymphocytes and red cells. What is the best diagnostic test and immediate treatment?

ACSF India ink, with amphotericin BBCSF culture for HSV, with oral valacyclovir after the resultCCSF polymerase chain reaction for HSV, with intravenous acyclovir started immediatelyDBrain biopsy only, with steroids

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

The answer and the reasoning

C. CSF polymerase chain reaction for HSV, with intravenous acyclovir started immediately

Herpes simplex encephalitis classically involves the temporal lobes and causes haemorrhagic necrosis. CSF HSV PCR is highly sensitive and specific and should not delay treatment; intravenous acyclovir should be started empirically as soon as the diagnosis is suspected, since delay worsens outcome.

Option by option

A. CSF India ink, with amphotericin B
India ink detects Cryptococcus, which does not produce this temporal lobe pattern.
B. CSF culture for HSV, with oral valacyclovir after the result
Culture is insensitive and oral therapy is inadequate for encephalitis.
C. CSF polymerase chain reaction for HSV, with intravenous acyclovir started immediately (correct)
Correct. PCR confirms the diagnosis and acyclovir must be started at once.
D. Brain biopsy only, with steroids
Biopsy is rarely needed now that PCR is available, and steroids alone do not treat the virus.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is C, CSF polymerase chain reaction for HSV, with intravenous acyclovir started immediately. Herpes simplex encephalitis classically involves the temporal lobes and causes haemorrhagic necrosis.

Why is "CSF India ink, with amphotericin B" not the answer?

India ink detects Cryptococcus, which does not produce this temporal lobe pattern.

Why is "CSF culture for HSV, with oral valacyclovir after the result" not the answer?

Culture is insensitive and oral therapy is inadequate for encephalitis.

Why is "Brain biopsy only, with steroids" not the answer?

Biopsy is rarely needed now that PCR is available, and steroids alone do not treat the virus.

What concept does this question test?

It tests Virology: herpesviruses in Microbiology. CSF HSV PCR is highly sensitive and specific and should not delay treatment; intravenous acyclovir should be started empirically as soon as the diagnosis is suspected, since delay worsens outcome.

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 Virology: herpesviruses?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.