An immunocompromised patient post-bone marrow transplant has fever unresponsive to broad-spectrum antibiotics. Chest CT shows a 2 cm pulmonary nodule with a halo sign. Serum galactomannan ELISA shows an ODI of 1.8 (cut-off > 0.5). The diagnosis and first-line treatment are:
- A Invasive pulmonary aspergillosis; voriconazole IV ✓
- B Cryptococcal pneumonia; liposomal amphotericin B + 5-flucytosine
- C Pneumocystis jirovecii pneumonia; trimethoprim-sulfamethoxazole
- D Mucormycosis; isavuconazole
Explanation
The halo sign (nodule surrounded by ground-glass opacity representing hemorrhagic infarction) on chest CT together with elevated serum galactomannan (a cell wall polysaccharide of Aspergillus spp., ODI ≥ 1.0 in haematological malignancy/HSCT per EORTC/MSG criteria) establishes probable invasive pulmonary aspergillosis. Voriconazole (a triazole) is the first-line treatment per IDSA guidelines. Galactomannan is NOT elevated in mucormycosis or cryptococcosis. PCP presents with bilateral ground-glass opacities, not a nodule with halo sign. Mucormycosis is treated with liposomal amphotericin B or isavuconazole.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.