Disease name and synonyms Mucormycosis (Zygomycosis) |
Fungi responsible Many fungi under the order Mucorales cause mucormycosis. They include Rhizopus oryzae (the most common), Rhizopus microsporus, Lichtheimia corymbifera, Lichtheimia ramosa, Rhizomucor pusillus, Mucor circinelloides, Apophysomyces elegans, Cunninghamella bertholletiae and Saksenaea vasiformis |
Disease description Mucormycosis is always an invasive infection and life-threatening. Without treatment mortality is nearly 100%. The common patterns of disease are:
The less common manifestations of mucormycosis are:
The clinical presentation is similar to invasive aspergillosis with little fever and few clinical features. Clues to the diagnosis of mucormycosis include progression of the disease on voriconazole or echinocandin therapy, high white blood cell count and elevated inflammatory markers, palatal ulcer with eschar, pulmonary nodules, consolidation or cavitation with negative Aspergillus antigen (galactomannan), Aspergillus PCR and/or beta 1,3B-D glucan. Sometimes haemoptysis is the presenting feature. Isolated renal mucormycosis presents abruptly with fever, loin pain, oliguria/anuria and haematuria, in previously well people. |
Frequency and global burden Up to 11% of filamentous fungal infections in leukaemia are mucormycosis, ~5,000 cases annually. In large series of patients with mucormycosis, about 15% of cases were related to malignancy and bone marrow transplantation, implying around 35,000 cases annually worldwide, probably a significant underestimate because of the difficulties in diagnosis. In 16-23% patients mucormycosis was reported as diabetes-defining illness. |
Underlying problems and at risk patients
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Diagnostic testing For pulmonary mucormycosis, a ‘reverse halo’ sign may an early radiographic feature of pulmonary mucormycosis. Most diagnoses of mucormycosis are made on direct microscopy and histology on a biopsy or sample collected from deep tissue. This is because there are no antigen tests or commercialized PCR and culture is positive in ~10% of cases only. Sometimes microscopy of respiratory fluids or surface swabs will reveal non-septate branching hyaline (not coloured) hyphae that are characteristic. In most cases, there are many fungal hyphae present, but being confident that they are not Aspergillus or another filamentous fungus, requires experience and enough material. The individual fungi responsible can be identified using molecular tools or by conventional microscopic means. Susceptibility testing is difficult and not validated for these fungi. |
Treatments Amphotericin B and posaconazole are the only active antifungal agents. Surgical debridement or resection is critically important in therapy, and antifungal therapy is secondary and moderately effective. Reversal of the underlying disease is also and important step |
Outlook and prognosis Approximately 70% of patients survive mucormycosis in the short term. Disseminated disease, bilateral pulmonary infection, cerebral infection, burn wound, uncontrolled malignancy and severe malnutrition are all poor prognostic features. |
Images
The following three images show a case of cutaneous mucormycosis.




Pulmonary mucormycosis in a patient with acute myeloid leukemia given voriconazole prophylaxis to prevent fungal infection. This was surgically removed and she went to complete her chemotherapy successfully.

Pulmonary mucormycosis in a patient with acute leukaemia.