A patient with uncontrolled Type 1 diabetes mellitus presents with severe facial pain, periorbital swelling, black necrotic nasal discharge, and right-sided ptosis. MRI shows infiltration of the right orbit and cavernous sinus. KOH preparation of nasal scraping shows broad (10–20 µm), aseptate (non-septate), ribbon-like hyphae with right-angle branching. What is the diagnosis and empirical antifungal treatment?

• A Invasive aspergillosis — treat with voriconazole 6 mg/kg IV every 12 hours × 2 doses then 4 mg/kg every 12 hours
• B Rhinocerebral candidiasis — treat with fluconazole 400 mg IV daily
• C Rhino-orbito-cerebral mucormycosis (ROCM) — treat with liposomal amphotericin B 5–10 mg/kg/day IV PLUS urgent surgical debridement and diabetic ketoacidosis correction ✓
• D Rhinosporidiosis — treat with dapsone 100 mg daily after surgical polypectomy

Explanation

Broad, non-septate (aseptate), ribbon-like hyphae with irregular branching at 90° angles (right-angle/wide-angle branching) on KOH mount is pathognomonic for Mucorales (Mucor, Rhizopus, Lichtheimia/Absidia). Rhino-orbito-cerebral mucormycosis (ROCM) occurs in diabetic ketoacidosis (iron availability in hyperglycaemic acidosis promotes fungal growth). Treatment: liposomal amphotericin B (drug of choice, less nephrotoxic) 5–10 mg/kg/day, urgent surgical debridement of necrotic tissue, and aggressive control of DKA. Aspergillus shows septate hyphae with 45° acute-angle branching; voriconazole is NOT effective for mucormycosis.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.