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Preeclampsia prevention — USMLE Step 3 MCQ

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HardOB/GYN (Prenatal / Contraception / Screening)Preeclampsia preventionUSMLE Step 3

A 39-year-old with newly diagnosed HIV (CD4 count 34/mm³) has diffuse bilateral ground-glass opacities and induced-sputum PCR positive for Pneumocystis jirovecii. Room-air PaO2 is 68 mm Hg and the alveolar-arterial oxygen gradient is 39 mm Hg. Trimethoprim-sulfamethoxazole is started. Which additional treatment is most appropriate?

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Correct answer: B — Add systemic corticosteroids within 72 hours of antimicrobial initiation

The best answer is “Add systemic corticosteroids within 72 hours of antimicrobial initiation”. This is moderate-to-severe Pneumocystis pneumonia because PaO2 is below 70 mm Hg and the A-a gradient is at least 35 mm Hg. Adjunctive corticosteroids should begin promptly, ideally with antimicrobial therapy and within 72 hours. The threshold is physiologic, not radiographic, and inhaled pentamidine is not adequate treatment for severe disease. The alternatives are less suitable because they mistime the intervention, omit a necessary component, or apply treatment for a different physiologic problem; the stem's decisive findings determine the sequence.

Reference: NIH, Adult and Adolescent Opportunistic Infection Guidelines: Pneumocystis Pneumonia: https://clinicalinfo.hiv.gov/en/guidelines/hiv-clinical-guidelines-adult-and-adolescent-opportunistic-infections/pneumocystis