Diffusely Invasive Mucormycosis of the Small Bowel in a Patient with Microbiologic Cultures and Tissue Biopsies Negative for Fungal Organisms

Abstract

Abstract Introduction/Objective Invasive mucormycosis can be a swiftly fatal medical emergency occurring in patients with uncontrolled diabetes. This angioinvasive fungus causes tissue necrosis, hemorrhage, and thrombosis and often develops in the sinonasal cavities where it can extend directly to the CNS or spread systemically to visceral sites like the GI tract. Here, we describe a patient whose small bowel resection shortly before death, revealed diffusely invasive mucormycosis despite that blood and body fluid cultures and tissue biopsies were negative for fungal organisms. Methods/Case Report Our patient is a 39 year old male with a history of uncontrolled diabetes, brought to our hospital in cardiac arrest and found to have fentanyl in his system. His labs showed severe metabolic and electrolyte derangements including diabetic ketoacidosis. His blood cultures revealed bacteremia but no fungal growth, and he was placed on antibiotics for sepsis. The patient developed compartment syndrome of his bilateral forearms, which were amputated and showed necrotic skeletal muscle but no fungal infection. The patient also developed facial necrosis concerning for mucormycosis, but nasal endoscopic and facial skin biopsies were negative for mucor. However, his abdominal CT showed diffuse mural thickening of his small bowel concerning for bowel ischemia, which prompted an exploratory laparotomy that revealed large segments of necrotic jejunum and ileum. While peritoneal fluids collected during the surgery yielded no fungal growth on culture, resected segments of necrotic small bowel showed massive presence of mucor with broad, pauci-septate, ribbon-like hyphae branching at right angles. Small bowel and mesenteric vessels showed angioinvasion by mucor with vasculitis and fibrin thrombi causing ischemic enteritis. Mucor was also noted diffusely invading small bowel muscularis propria, adventitia, and mesenteric fat, and small bowel also showed ulceration, hemorrhage, and transmural and mesenteric fat necrosis. Unfortunately, a few days after his surgery, the patient expired from multi-organ failure and septic shock before he could receive anti-fungal therapy for mucormycosis. Results (if a Case Study enter NA) NA Conclusion Mucormycosis is a rapidly growing, angioinvasive, and potentially lethal fungal infection that must be promptly recognized. This report documents an unusual case of invasive mucormycosis of the small bowel that went undetected in a severely ill patient whose blood and peritoneal cultures and tissue biopsies were all negative for fungal organisms.