Aspergillus Halo Sign CGD — SCE Infectious Diseases MCQ

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ModerateImmunocompromised HostAspergillus Halo Sign CGDSCE Infectious Diseases

A 40-year-old man with chronic granulomatous disease (CGD) develops pneumonia with CT showing consolidation and the 'halo sign' (ground-glass opacity surrounding a nodule). What is the most likely pathogen?

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Correct answer: E — Aspergillus fumigatus — the halo sign represents haemorrhagic infarction around an angioinvasive Aspergillus nodule; Aspergillus is the leading cause of mortality in CGD

Aspergillus fumigatus is the most important life-threatening pathogen in CGD and the leading cause of death. The halo sign on CT (ground-glass attenuation surrounding a pulmonary nodule, representing haemorrhagic infarction from angioinvasive aspergillosis) is a classic early radiological finding. CGD patients are predisposed to Aspergillus because the defective NADPH oxidase cannot generate the reactive oxygen species needed for fungal killing. Lifelong Itraconazole prophylaxis reduces (but does not eliminate) Aspergillus risk. Treatment: Voriconazole (or Liposomal Amphotericin B) plus surgical debridement if localised.

Reference: UK PID guidelines 2023 – CGD; NICE 2024; IDSA 2016 – Aspergillosis