A 38-year-old man with HIV infection (CD4 count 88 cells/µL, viral load 68,000 copies/mL, not yet on ART) presents with progressive dyspnoea, dry cough, low-grade fever, and bilateral perihilar ground-glass infiltrates on HRCT. LDH is 480 U/L. His oxygen saturation drops to 88% on exertion. Which prophylaxis/treatment consideration is the MOST important additional adjunct to first-line TMP-SMX in moderate-to-severe PCP?

• A ART should be initiated within 2 weeks to immediately reduce viral load and allow immune reconstitution during PCP treatment
• B Primaquine-clindamycin should replace TMP-SMX immediately as TMP-SMX has no role in moderate PCP
• C Adjunctive pentamidine infusion prevents TMP-SMX resistance emergence in moderate PCP
• D Corticosteroids (prednisolone 40 mg BD) should be added within 72 hours when PaO2 < 70 mmHg or A-a gradient > 35 mmHg ✓

Explanation

Adjunctive corticosteroids are a Class I recommendation in moderate-to-severe PCP (PaO2 < 70 mmHg on room air or alveolar-arterial O2 gradient > 35 mmHg) — they reduce mortality by attenuating the inflammatory response to dying Pneumocystis jirovecii organisms releasing cell wall components during PCP treatment. The ACTG 080 study established this benefit; prednisolone 40 mg BD × 5 days → 40 mg OD × 5 days → 20 mg OD × 11 days is the standard regimen. ART should be initiated within 2–4 weeks of PCP treatment initiation but not before stabilisation; immediate initiation may cause IRIS (PCP-IRIS). TMP-SMX remains first-line.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.