A 30-year-old HIV-positive man (CD4 count 40 cells/µL, viral load detectable) presents with fever, dry cough, and progressive dyspnoea. CXR shows bilateral perihilar interstitial infiltrates. LDH is 520 IU/L. SpO2 is 82% on room air. The most appropriate treatment and its adjunctive therapy are:

• A Azithromycin monotherapy for atypical pneumonia
• B IV amphotericin B for Cryptococcus
• C Start antiretroviral therapy immediately without specific antipneumocystis treatment
• D Trimethoprim-sulfamethoxazole + adjunctive corticosteroids (for PaO2 < 70 mmHg or A-a gradient > 35) ✓

Explanation

The clinical picture — severe AIDS (CD4 <200), bilateral perihilar interstitial infiltrates, elevated LDH, and hypoxia in a young patient — is classic for Pneumocystis jirovecii pneumonia (PCP). First-line treatment is high-dose TMP-SMX (15–20 mg/kg/day of TMP component). Adjunctive corticosteroids are indicated when PaO2 < 70 mmHg or A-a gradient > 35 mmHg, as shown in landmark trials, reducing mortality by ~50%. The SpO2 of 82% confirms severe hypoxia.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.