Mucormycosis

Key Features

Essentials of Diagnosis

• Most common cause of non-Aspergillus invasive mold infection

• Risk factors

  • Uncontrolled diabetes

  • Hematologic malignancy

  • Hematologic stem cell or solid organ transplantation

  • Direct inoculation of wounds (trauma, burns)

  • COVID-19

• Lungs, rhino-orbital-cerebral regions, 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), Saksenaea, Apophysomyces, 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

Clinical Findings

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

  • Diabetes is associated with rhino-orbital-cerebral disease

  • Hematologic malignancy predisposes to pulmonary infection

• 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

Diagnosis

• Biopsy of involved tissue is almost always required; the organisms appear in tissue as broad, branching nonseptate hyphae on histology

• Molecular identification (eg, PCR) from tissue or blood may aid diagnosis

• Cultures are frequently negative

• Chest CT: a reverse "halo sign" (focal area of ground glass diminution surrounded by a ring of consolidation) may be seen

Treatment

• Optimal therapy involves

  • Reversal of predisposing conditions (if possible)

  • Surgical debridement

  • Prompt antifungal therapy

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

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

  • Less severe disease

  • Step-down therapy after disease stabilization

  • Salvage therapy due to poor response to or tolerance of amphotericin

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

Outcome

Prognosis

• Even with prompt treatment, prognosis is guarded

References