A 35-year-old HIV-positive man (CD4 count 45 cells/μL) presents with bilateral interstitial infiltrates, dry cough, and oxygen saturation of 86% on room air. LDH is markedly elevated. BAL reveals cysts staining with Grocott methenamine silver. The CORRECT management with adjunctive therapy is:
- A IV pentamidine isethionate; no adjunctive corticosteroids needed
- B Aerosolised pentamidine; add fluconazole for concurrent candida prophylaxis
- C Oral trimethoprim-sulfamethoxazole (TMP-SMX) high dose + prednisolone 40 mg twice daily if PaO₂ < 70 mmHg ✓
- D Liposomal amphotericin B because TMP-SMX has no activity against Pneumocystis
Correct answer: C. Oral trimethoprim-sulfamethoxazole (TMP-SMX) high dose + prednisolone 40 mg twice daily if PaO₂ < 70 mmHg
Explanation
Pneumocystis jirovecii pneumonia (PCP) in HIV is confirmed by Grocott/GMS staining of BAL. First-line treatment is high-dose oral TMP-SMX (15–20 mg/kg/day TMP component) for 21 days. Adjunctive corticosteroids (prednisolone 40 mg BD for 5 days then taper) are recommended when PaO₂ < 70 mmHg or A-a gradient > 35 mmHg, as they reduce the inflammatory cytokine surge and mortality by 50%. IV pentamidine is reserved for TMP-SMX intolerance. Amphotericin B is for fungal infections; PCP is not a true fungus in terms of antifungal susceptibility.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.