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Pneumocystis jirovecii pneumonia — SCE Respiratory MCQ

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HardRespiratory InfectionsPneumocystis jirovecii pneumoniaSCE Respiratory

A 39-year-old man with advanced HIV presents with dry cough, fever and exertional desaturation. CD4 count is 48 cells/mm3, CXR shows bilateral perihilar interstitial shadowing and LDH is elevated. ABG on air shows PaO2 8.2 kPa. What is the most likely diagnosis?

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Correct answer: E — Pneumocystis jirovecii pneumonia

Subacute dry cough, perihilar interstitial infiltrates, exertional desaturation and low CD4 count strongly suggest Pneumocystis jirovecii pneumonia. TB remains a differential in HIV, but this radiological and physiological pattern is more typical of PJP. Hypoxaemia also affects treatment because adjunctive corticosteroids may be indicated in moderate to severe disease.

Reference: BHIVA Opportunistic Infection Guideline; BNF Co-trimoxazole