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HIV preexposure prophylaxis — USMLE Step 2 CK MCQ

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HardPreventive Medicine & BiostatisticsHIV preexposure prophylaxisUSMLE Step 2 CK

A 29-year-old man reports condomless intercourse 6 weeks ago with a partner who has now been diagnosed with secondary syphilis. He has no symptoms or examination findings, and today's treponemal and nontreponemal tests are negative. He has no penicillin allergy. What is the most appropriate management?

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Correct answer: A — Give benzathine penicillin G 2.4 million units intramuscularly now

The best answer is “Give benzathine penicillin G 2.4 million units intramuscularly now”. Exposure to a partner with secondary syphilis occurred within 90 days. CDC guidance calls for presumptive treatment for early syphilis even when the exposed partner is asymptomatic and initial serology is negative, because tests can remain nonreactive during early incubation. A single intramuscular dose of benzathine penicillin G is the appropriate regimen. Observation alone risks missed incubating infection; short doxycycline is not the alternative early-syphilis regimen, and cerebrospinal-fluid evaluation or intravenous penicillin is reserved for neurologic, ocular, or otic disease.

Reference: CDC STI Treatment Guidelines: Syphilis—Management of Sex Partners: https://www.cdc.gov/std/treatment-guidelines/syphilis.htm