Infectious Disease Compendium

Mucormycosis

Microbiology

Molds. Includes, but limited to, Absidia, Cunninghamella, Mortierellaceae, Mucor, Rhizomucor, Rhizopus, Saksenaea, Apophysomyces trapeziformis. Aka zygomycosis. Broad non septate hyphae.

Epidemiologic Risks

Environmental, it lives in decaying vegetable matter and soon to be decaying matter. Deferoxamine is a risk factor in dialysis patients.

Necrotizing soft-tissue infections due to Apophysomyces trapeziformisa and other agents of mucor were reported after a US tornado injuries. In France post -traumic mucor was often due to Apophysomyces elegans complex and Saksenaea vasiformis (PubMed).  Other environmental injuries (volcanos and tsunamis) have lead to outbreaks.

And Scorpion stings. Really (PubMed).

Syndromes

- Invasive disease: both local (esp lung) and disseminated in the profoundly immunoincompetent. Serial (1-3)-Beta-D-glucan has good diagnostic parameters in cancer patients (PubMed).

- Skin disease, especially in burn patients.

- Invasive pneumonia: especially in patients with hematologic malignancies and on steroids. Pulmonary moulds may best be found early with a chest CT (PubMed) that demonstrates a halo (Aspergillus) or reverse halo sign (Mucormycosis) (PubMed).

Pulmonary mucor may be masked by bacterial infection: "...3 cases that highlight a misleading presentation of mucormycosis in which bacteria were identified as the causal etiology of necrotizing cavitary lung disease on initial diagnostic evaluation, but subsequent evolution and reassessment of the same cavitary disease demonstrated underlying mucormycosis. This bacterial and apparently parsimonious presentation, which we have termed the green herring syndrome (PubMed)." Green herring, huh? I suppose that if you describe the syndrome you get to name it and it goes along with the meaning of red herring but it rings wrong to my ear.

- Rhinocerebral: in diabetic ketoacidosis and patients with hematologic malignancies and on steroids. Also been found in dialysis patients on chelators. It invades along the muscle of the eyes into the brain. Look for a fixed eye and/or unilateral proptosis. A real emergency if found.

In transplant patients it tends to occur late, > three months after transplant (Review).

Treatment

Debride if at all possible. Lipid Amphotericin B has been the treatment of choice but it often doesn't do squat, although the 10 mg/kg of lipid amphotericin B may be the best bet (Review).

Depending on the species, posaconazole 800 mg/day look promising in vitro and is maybe the treatment of choice (PubMed), although there are no head to head trials. Resistant to voriconazole. Despite resistance to caspofungin, when combined with lipid amphotericin B, may have increased survival (PubMed). Isavuconazole as well.

Should combination therapy be used? No trials but there is some suggestion it is more effective maybe perhaps (PubMed). Others have shown no benefit from combinations (amphotericin-echinocandin) (PubMed).

Notes

Deferoxamine used for chelation is also a risk factor.