Pathophysiology
1) caused by infection with yeast organisms Mucor, Rhizopus, Rhizomucor, Cunninghamella, Absidia 2) can affect the sinuses, lungs, and GI tract
Signs and Symptoms
Sinus – 1) dull sinus pain 2) low-grade fever 3) nasal stuffiness 4) thin bloody nasal discharge 5) progresses over several days to high fever, mental confusion, double vision, ptosis, proptosis, eye pain and decreased eye movement, necrotic nasal turbinates, necrotic hard palate (usually does not cross midline), inflamed skin on cheek on involved side, blindness, coma Pulmonary – 6) progressive, severe pneumonia 7) high fever 8) shock Gastrointestinal – 9) ulcers with perforation common
Characteristic Test Findings
Radiology – 1) carotid and cavernosus sinus thrombosis on MRA 2) opacification of involved sinus on CT 3) cavitation of lung lesions on CT
Histology/Gross Pathology
1) organisms grow as molds with broad, nonseptate hyphae 2) vascular invasion with ischemic and/or hemorrhagic necrosis
Associated Conditions
increased incidence occurs in – 1) poorly controlled diabetics/diabetic ketoacidosis (sinus) 2) transplant patients (sinus and lung) 3) leukemia/lymphoma (sinus and lung) 4) deferoxamine therapy (sinus and lung) 5) chronic steroid use (sinus and lung) 6) uremia (GI tract) 7) diarrheal diseases (GI tract) 8) severe malnutrition (GI tract) 9) burn wounds
Inheritance/Epidemiology
1) organisms are ubiquitous and occur in high-sugar content foods, dung, and decaying vegetation 2) no person-to-person transmission
Treatment
1) control diabetes 2) decrease immunosuppression 3) surgical debridement of craniofacial lesions 4) intravenous amphotericin B
Tips for USMLE
1) it is very difficult to get these organisms to grow from samples of infected tissue 2) if the patient is a 48 year-old man who is admitted for severe diabetic ketoacidosis and on exam has black eschars in his nasal cavity and complains of eye pain, think mucormycosis
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