ESSENTIALS OF DIAGNOSIS
The most common cause of non-Aspergillus invasive mold infection.
Predisposing factors: poorly controlled diabetes, leukemia, bone marrow or organ transplant, trauma with wound contamination by soil.
Pulmonary, rhinocerebral, and skin are the most common disease sites.
Rapidly fatal without multidisciplinary interventions.
The term “mucormycosis” is applied 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, deferoxamine therapy, and treatment with corticosteroids or cytotoxic drugs.
The invasive disease of the sinuses, orbits, and 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 is seen in patients who have received cytotoxic chemotherapy.
No serologic or laboratory findings assist with diagnosis and blood cultures are unhelpful. A reverse halo sign may be seen on chest CT. Biopsy of involved tissue remains the cornerstone of diagnosis, although cultures are frequently negative. The organisms appear in tissues as broad, branchoing nonseptate hyphae.
Optimal therapy of mucormycosis involves a reversal of predisposing conditions (if possible), surgical debridement, and prompt antifungal therapy. A prolonged course of a lipid preparation of intravenous amphotericin B (5 mg/kg) should be started early. Based on in vitro susceptibility, posaconazole tablets 300 mg/d orally is generally used after the disease has been stabilized. 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. Limited data are suggesting beneficial synergistic activity when amphotericin and caspofungin are used in combination for mucormycosis. Despite favorable animal studies, a pilot study in humans incorporating adjunctive iron chelation therapy with deferasirox demonstrated a higher mortality rate than antifungal therapy alone. Control of diabetes and other underlying conditions, along with extensive repeated surgical removal of necrotic, nonperfused tissue, is essential. Even when these measures are introduced in a timely fashion, the prognosis remains guarded. The historical 4-week mortality rate is 40%, although better response rates have been noted since 2000
Katragkou A et al. Why is mucormycosis more difficult to cure than more common mycoses? Clin Microbiol Infect. 2013 Nov 27. [Epubaheadof print][PMID:24279587] Neblett Fanfair R et al. Necrotizing cutaneous mucormycosis after a tornado in Joplin, Missouri, in 2011.N Engl J Med. 2012 Dec 6;367(23):2214-25. [PMID:23215557 Pagano L et al. Combined antifungal approach for the treatment of invasive mucormycosis in patients with hematologic diseases: a report from the SEIFEMand FUNGISCOPE registries.Haematologica.2013 Oct:98(10):el27-30. [PMID:23716556]