Mucormycosis

Mucormycosis is a rare but serious invasive fungal infection caused by fungi in the order Mucorales, most often Rhizopus, Mucor, and Absidia. These environmental molds are usually contracted through inhalation of spores, though infection can also occur via ingestion or cutaneous inoculation. The disease typically affects people with impaired immune defenses or metabolic disorders.

Clinical forms vary by site. Rhino-orbito-cerebral mucormycosis commonly arises in people with poorly controlled diabetes or ketoacidosis and presents with facial swelling, sinus symptoms, and possible ocular involvement. Pulmonary mucormycosis is more frequent in neutropenic or critically ill patients. Cutaneous mucormycosis follows trauma or surgical wounds. Gastrointestinal and disseminated forms are less common but carry high mortality.

Pathophysiology involves rapid angioinvasion by the fungi, leading to thrombosis, tissue ischemia, and necrosis. Histopathology shows broad, nonseptate or sparsely septate hyphae with irregular or right-angle branching, often in tissue around blood vessels.

Diagnosis relies on a high index of suspicion, imaging to assess extent, and tissue biopsy for histology. Microscopy and culture can identify the organism, but cultures may be negative; molecular tests may aid confirmation.

Treatment requires urgent, combined measures. First-line therapy is systemic antifungal treatment with liposomal amphotericin B, alongside prompt surgical debridement or resection of necrotic tissue. After stabilization, step-down therapy with posaconazole or isavuconazole may be used. Management also includes reversal of underlying risk factors, such as glycemic control, reduction of immunosuppression when possible, and correction of iron overload. Outcome depends on the site and timeliness of treatment, with mortality remaining high in many cases.