Adhesive small bowel obstruction — USMLE Step 3 MCQ

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HardSurgery (post-operative, follow-up)Adhesive small bowel obstructionUSMLE Step 3

A 37-year-old with a persistent cerebrospinal fluid leak has never received a pneumococcal vaccine. Which plan is a complete and correctly timed risk-based schedule?

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Correct answer: E — Give PCV20 now with no additional pneumococcal dose

The best answer is “Give PCV20 now with no additional pneumococcal dose”. PCV20 alone completes risk-based pneumococcal vaccination. The alternative conjugate strategy is PCV15 followed by PPSV23, for which a CSF leak permits an 8-week minimum interval; substituting another conjugate vaccine, reversing the sequence, or adding PPSV23 after PCV20 does not match the schedule. An adult age 19–49 with a cerebrospinal fluid leak and no prior pneumococcal vaccine may receive PCV20 or PCV21 alone, or PCV15 followed by PPSV23; the minimum PCV15-to-PPSV23 interval may be 8 weeks. The alternatives use a different threshold, timing, population, or intervention and therefore do not match the clinical facts presented.

Reference: CDC: Risk-based Pneumococcal Vaccination Recommendations: https://www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/risk-indications.html