Mucormycosis (zygomycosis) is a rapidly progressive, often fatal invasive fungal infection caused by fungi of the order Mucorales (Rhizopus, Mucor, Rhizomucor), which are ubiquitous environmental molds. The organisms have a predilection for patients with diabetic ketoacidosis (DKA), neutropenia, organ transplant immunosuppression, iron overload, and deferoxamine therapy. In DKA, the combination of acidosis (which impairs neutrophil phagocytosis and increases free serum iron by displacing iron from transferrin) and hyperglycemia (which provides a growth substrate) creates an ideal environment for fungal proliferation. The fungal hyphae are characteristically wide, pauciseptate, and branch at right angles, and have a strong tropism for blood vessel invasion (angioinvasion), causing thrombosis, tissue infarction, and rapid tissue destruction. Rhinocerebral mucormycosis is the most common form, beginning in the sinuses and extending through the orbit into the brain. The nurse monitors for facial pain, nasal congestion with black necrotic eschar on the palate or nasal mucosa, proptosis, cranial nerve palsies, and mental status changes, administers IV amphotericin B as prescribed, coordinates urgent surgical debridement, corrects DKA aggressively, monitors renal function during antifungal therapy, and recognizes the extremely high mortality...