Mucorycoses B46.5

Paltauf, 1885

Opportunistic systemic mycosis (see mycosis below) caused by pathogens of the fungal genus Mucor (Mucorales). Mucormycetes (Mucorales) are ubiquitously distributed, rather primitive filamentous fungi which are only weakly pathogenic.

As typical opportunistic pathogens, they can only cause an infection if the host organism is appropriately dispositioned. In patients with immunosuppression or metabolic diseases (e.g. diabetes mellitus with ketoacidosis) and iron overload, the fungi can penetrate via the mucous membranes and multiply in the tissue.

If they invade the vascular system, these fungi continue to grow intravascularly and develop "pseudothrombi" there. Occasionally, individual hyphae differentiate sexually and the "male" or female cells fuse into a zygospore.

Molds; for (immunodeficient) people pathogenic are mainly:

• absidia corymbifera
• ramosa absidia
• Mucor hiemalis
• mucor pusillus
• Mucor plumbeus
• mucor racemosus
• Rhizopus stolonifer (Rhizopus nigricans)
• Rhizopus oryzea (Rhizopus arrhizus)
• Rhizopus microsporus (Rhizopus cohnii).

Manifestations:

• Rhino-orbito-cerebral: most common form in predisposed patients, especially in patients with diabetes mellitus. Possible symptoms: sinusitis with bloody nasal secretions, periorbital swelling, fever, redness, facial pain, headache, endopthalmitis; in case of cranial nerve deficits: possibly ptosis, mydriasis, loss of visual acuity.
• Lung: rapidly progressive, refractory pneumonia, fever, dyspnoea, cough, haemoptysis.
• Skin: Traumatic transfer of mould spores to the skin.
• Gastrointestinal: Infection by ingestion. Onset of symptoms with abdominal pain symptoms, nausea, vomiting, fever, risk of intestinal perforation and consecutive peritonitis.
• CNS (disseminated form): CNS involvement usually in the context of hemotogenic generalization of mucormycosis. Less common is spread per continuitatem (starting from rhino-orbital infestation), seizures, neurological deficits, loss of consciousness. The lethality rate in CNS infestation is high.

Incidence: 1-10/100,000 inhabitants/year; patients with risk factors must be expected to have an increasing incidence.

Inhalation of the fungi with the breath, via the intestinal tract, less frequently via traumatic inoculation into the skin or via wound contamination.

Generally occurs only in predisposed patients. E.g. patients with diabetes mellitus, burns, immunosuppression (see also organ transplants, skin changes; chemotherapy for leukemia patients), malignancies, uremia, candidiasis and aspergillosis, HIV infection.

Mainly craniofacial, brain, lungs, abdominal and pelvic area, skin.

Imaging diagnostics (lung infestation, rhino-orbital infestation)

CT-guided percutaneous lung biopsy. Skin: Direct biopsy of a lesion.

Histological evidence: PAS or Grocott stain.

PCR diagnostics from biopsy material

Culture (Sabourand glucose agar) from biopsy material

differentiation of isolates using MALDI-TOF can be attempted.

Aspergillosis; nocardiosis; anthrax of the skin; actinomycosis of the skin; coccidioidomycosis (see also mycoses of the skin), infections through entomophthorales

Skin: Surgical treatment if necessary, local imidazole derivatives such as bifonazole (e.g. Mycospor cream) or ketoconazole (e.g. Nizoral cream).

• Early use of Amphotericin B (e.g. Amphotericin B dry substance) slowly over 8-10 hours i.v. Initial: 0,1 mg/kg bw/day, increasing to 0,8-1 mg/kg bw/day. Therapy until healing and 2-3 weeks beyond disease activity.
• Alternatively: Liposomal amphotericin B (e.g. AmBisome) initial: 1 mg/kg bw i.v.; if required, increase stepwise to 3 mg/kg bw. Possibly combination with Flucytosin i.v. (e.g. Ancotil) 150-200 mg/kg bw/day. Therapy successes with Fluconazole (400 mg/day i.v.) are described.
• Alternative: Posaconazol: 2 times/day 400 mg p.o. (daily dose 800 mg) or 4 times/day 200 mg p.o.

Unfavourable, especially in rhinocerebral and pulmonary form high and rapid lethality (> 50%). In cerebral and disseminated form, lethality > 90%.

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