Mucormycosis

Essentials of Diagnosis

• Most common cause of non-Aspergillus invasive mold infection

• Risk factors

  • Uncontrolled diabetes

  • Leukemia

  • Transplant recipient

  • Wound contamination by soil

• Pulmonary, rhinocerebral, and skin are most common disease sites

• Rapidly fatal without multidisciplinary interventions

General Considerations

• The term "mucormycosis" applies to opportunistic infections caused by members of the genera Rhizopus, Mucor, Lichtheimia (formerly Absidia), and Cunninghamella

• Predisposing conditions include

  • Hematologic malignancy

  • Stem cell transplantation

  • Solid organ transplantation

  • Diabetic ketoacidosis

  • Chronic kidney disease

  • Desferoxamine therapy

  • Use of corticosteroids or cytotoxic drugs

• Invasive disease of the sinuses, orbits, and the lungs may occur

• Necrosis is common due to hyphal tissue invasion that may manifest as ulceration of the hard palate or nasal palate or hemoptysis

• Widely disseminated disease can occur

• No biochemical assays aid in diagnosis

• Blood cultures are unhelpful

• Molecular identification (eg, PCR) from tissue and/or mass spectrometry-base detection of a panfungal serum disaccharide may be helpful in specialized centers

• A reverse halo sign may be seen on chest CT

• Cultures frequently negative

• Biopsy almost always required for diagnosis; the organisms appear in tissues as broad, branching nonseptate hyphae

• Optimal therapy involves

  • Reversal of predisposing conditions (if possible)

  • Surgical debridement

  • Prompt antifungal therapy

• A prolonged course of a lipid preparation of intravenous liposomal amphotericin B (5–10 mg/kg with higher doses possibly given for CNS disease) should be started early

• Oral posaconazole (300 mg/day) or isavuconazole (200 mg every 8 hours for 1–2 days, then 200 mg daily thereafter) can be used

  • For less severe disease

  • As step-down therapy after disease stabilization

  • As salvage therapy due to poor response to or tolerance of amphotericin

• In patients with breakthrough invasive mold infections despite mold-active antifungal prophylaxis, clinicians should initiate treatment with a different class of antifungal agents than was used for prophylaxis

• Combination therapy with amphotericin and posaconazole is not proven but is commonly used because of the poor response to monotherapy

• Other azoles are not effective

Prognosis

• Even with prompt treatment, prognosis is guarded