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Chronic Granulomatous Disease — RACP Adult Medicine MCQ

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HardInfectious DiseasesChronic Granulomatous DiseaseRACP Adult Medicine

A 3-year-old boy has recurrent staphylococcal skin abscesses, lymphadenitis, and a liver abscess. Catalase-positive organisms predominate (S. aureus, Aspergillus). Nitroblue tetrazolium (NBT) test is abnormal (no colour change). Dihydrorhodamine (DHR) flow cytometry shows absent oxidative burst. What is the most likely diagnosis?

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Correct answer: E — Chronic granulomatous disease

Recurrent infections with catalase-positive organisms (S. aureus, Aspergillus, Serratia, Nocardia), granuloma formation, and absent oxidative burst (abnormal NBT/DHR) is chronic granulomatous disease. CGD results from NADPH oxidase deficiency — phagocytes cannot generate reactive oxygen species to kill catalase-positive organisms. X-linked (gp91phox mutation) is most common. Treatment: prophylactic TMP-SMX + itraconazole, interferon-gamma. Curative: allogeneic SCT or gene therapy.

Reference: ASCIA – 2024 – PID; ESID 2024