Zygomycosis
Zygomycosis is not a very common disease compared to other opportunistic mycoses, such as candidiasis and aspergillosis. The first case was described in 1885, and its description was complete enough to suggest that Absidia corymbifera was the causative agent of the disease.
Initially, most of the causative agents of the infection were attributed to fungi of the genus Mucor, however, they were later reclassified to different genera and families within the order Mucorales.
Soon after, however, it became clear that Rhizopus spp. and not Mucor spp. predominate among the causative agents of zygomycosis.
With the accumulation of data on this pathology, the obvious connection of zygomycosis with oncological diseases, diabetes mellitus, long-term use of antibiotics, corticosteroids, deferoxamines, immunosuppressants became known.
With the improvement of diagnostic methods, the spectrum of causative agents has expanded. Along with representatives of the genera Rhizopus, Mucor, and Absidia, species of the genera Rhizomucor, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. began to be identified.
What are the risk factors?
Zygomycosis, like many other invasive mycoses, develops preferentially in immunocompromised patients.
The main risk factors in this category of patients are – decompensated diabetes mellitus, oncological and hematological pathologies, neutropenia / the absolute number of neutrophils is less than 0.5 *109 for a week or more /, AIDS, condition after transplantation of organs.
Long-term immunosuppressive and cytostatic therapy is also essential, that is, chemotherapy in a slightly more limited sense, long-term glucocorticoids and deferoxamine.
Recently, a number of cases of this type of fungal infection have been described in allogeneic organ transplant recipients on voriconazole prophylaxis.
All of these cases show an increased incidence among patients receiving pre- and post-operative preparation from this antifungal preparation, but whether this medication actually increases the risk of developing zygomycosis is currently not known. known.
Most of the described cases of the disease were on the background of voriconazole therapy, developed in patients who received high doses of corticosteroids due to the presence of another underlying pathology.
However, the uniformity of occurrence of zygomycosis in patients taking this antifungal is noteworthy. Voriconazole has a broad spectrum of activity against Aspergillus spp., Candida spp., Scedosporium spp., but is not active against zygomycetes.
Therefore, it can be assumed that voriconazole, preventing the development of other invasive invasive mycoses, thereby increasing the life expectancy of people with a compromised immune system, but at the same time increasing the probability of their infection with zygomycetes.
Clinical picture
There are 5 main clinical variants of the disease. Usually they are associated with the localization of the primary focus of infection and the entrance door of infection.
Zygomycosis is subdivided into rhinocerebral (approximately 50% of cases), pulmonary – 20%, skin – 10%, gastrointestinal – 10%, and also other rarer forms of the disease.
Usually, the different variants develop in relation to certain risk factors.
For example, in patients with diabetic ketoacidosis, the occurrence of the rhinocerebral variant of the disease and less often the pulmonary or generalized form is typical. Why precisely the rhinocerebral form develops in ketoacidosis remains unclear.
Treatment of zygomycosis
When applying the therapeutic approach, it is necessary to take into account 4 factors – the speed of diagnosis, treatment of the main disease – if it is possible to completely exclude it as a risk factor, surgical removal of the affected tissues and appropriate antifungal therapy.
