Mucormycosis is an invasive, angioinvasive fungal infection caused by ubiquitous environmental molds of the order Mucorales (Rhizopus, Mucor, Lichtheimia, Cunninghamella, Apophysomyces). The rhino-orbital-cerebral form begins with spore inhalation and germination in nasal turbinates and paranasal sinuses, followed by invasion of arterial walls causing thrombosis, tissue infarction, and contiguous spread to orbit and brain through ethmoid plates, cribriform plate, or cavernous sinus. Risk factors include diabetic ketoacidosis (most common globally), hematologic malignancies and stem cell transplant with profound neutropenia, deferoxamine therapy increasing free iron, severe COVID-19 with corticosteroid use, and rarely solid organ transplantation, AIDS, and major trauma.
Initial symptoms include facial pain and swelling, nasal congestion with bloody discharge, periorbital pain, and headache, often progressing within hours to days. Examination may reveal black nasal eschar, palatal necrosis, eyelid swelling, proptosis, ophthalmoplegia, and decreased visual acuity. Cerebral involvement causes altered mental status, seizures, and focal deficits. Imaging with CT and MRI shows pansinusitis with bone erosion, orbital extension with extraocular muscle and optic nerve involvement, cavernous sinus thrombosis, and brain infarcts or abscesses. Diagnosis requires endoscopic biopsy with histopathology demonstrating broad, ribbon-like, non-septate hyphae with right-angle branching invading vessels and tissue, supplemented by fungal culture and PCR.
Mortality without aggressive treatment exceeds 50-80%. Therapy combines emergency reversal of underlying immunosuppression (insulin therapy and ketoacidosis correction in DKA, granulocyte colony stimulating factor for neutropenia, corticosteroid taper), wide surgical debridement of all necrotic tissue including orbital exenteration when needed, and prolonged antifungal therapy with liposomal amphotericin B (5-10 mg/kg/day) for 4-6 weeks followed by oral isavuconazole or posaconazole step-down for 3-6 months. Adjunctive measures include hyperbaric oxygen, iron chelation with deferasirox, and aggressive supportive care. Survivors often have major facial deformities and visual loss requiring complex reconstruction.