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Mucormycosis refers to infection caused by diverse fungal species, including Rhizopus, Rhizomucor, Absidia, and Mucor. Symptoms most frequently result from invasive necrotic lesions in the nose and palate, causing pain, fever, orbital cellulitis, proptosis, and purulent nasal discharge. CNS symptoms may follow. Pulmonary symptoms are severe and include productive cough, high fever, and dyspnea. Diagnosis is primarily clinical, requires a high index of suspicion, and is confirmed by histopathology and culture. Treatment is with IV amphotericin B and surgery to remove necrotic tissue.
Infection is most common among immunocompromised people, in patients with poorly controlled diabetes, and in patients receiving the iron-chelating drug deferoxamine.
The most common form of mucormycosis is
However, primary cutaneous, pulmonary, or GI lesions sometimes develop, and hematogenous dissemination to other sites can occur.
Symptoms and Signs
Rhinocerebral infections are usually severe and frequently fatal unless diagnosed early and treated aggressively. Necrotic lesions appear on the nasal mucosa or sometimes the palate. Vascular invasion by hyphae leads to progressive tissue necrosis that may involve the nasal septum, palate, and bones surrounding the orbit or sinuses. Manifestations may include pain, fever, orbital cellulitis, proptosis, purulent nasal discharge, and mucosal necrosis.
Progressive extension of necrosis to the brain can cause signs of cavernous sinus thrombosis, seizures, aphasia, or hemiplegia. Pulmonary infections resemble invasive aspergillosis. Pulmonary symptoms (eg, productive cough, high fever, dyspnea) are severe. Cutaneous Rhizopus infections have developed under occlusive dressings but more often result from trauma when the injured areas are contaminated with soil.
Diagnosis
Diagnosis requires a high index of suspicion and painstaking examination of tissue samples for large nonseptate hyphae with irregular diameters and right-angle branching patterns; the examination must be thorough because much of the necrotic debris contains no organisms. For unclear reasons, cultures may be negative, even when hyphae are clearly visible in tissues. CT and x-rays often underestimate or miss significant bone destruction.
Treatment
Effective therapy requires that diabetes be controlled or, if at all possible, immunosuppression be reversed or deferoxamine be stopped.
IV amphotericin B must be used because azoles are ineffective, although recent evidence suggests that posaconazole with or without an echinocandin may be effective. Most experts use high doses of lipid formulations of amphotericin B (up to 10 to 20 mg/kg/day).
Complete surgical debridement of necrotic tissue is critical.
Last full review/revision April 2009 by Alan M. Sugar, MD
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