PJP Diagnosis — RACP Adult Medicine MCQ

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EasyInfectious DiseasesPJP DiagnosisRACP Adult Medicine

A 35-year-old man diagnosed with HIV has a CD4 count of 50 cells/µL and develops progressive dyspnoea with bilateral reticulonodular infiltrates on CXR. His serum LDH is 850 U/L. Induced sputum shows cysts on silver stain. What is the diagnosis?

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Correct answer: B — Cryptococcal pneumonia

Bilateral interstitial infiltrates with markedly elevated LDH in severely immunocompromised HIV (CD4 <200) and cysts on silver stain (Gomori methenamine silver – GMS) of induced sputum is diagnostic of Pneumocystis jirovecii pneumonia (PJP). LDH elevation correlates with disease severity and prognosis. Beta-D-glucan is also elevated. Treatment is high-dose IV TMP-SMX for 21 days. Adjunctive prednisolone is indicated when PaO₂ <70 mmHg or A-a gradient >35 mmHg.

Reference: eTG – 2025 – Antibiotic Guidelines; ASHM – 2024 – HIV/OI Management