Date Published: August 20, 2020
Publisher: Wolters Kluwer
Author(s): Pankaj Aggarwal, Harsh Patel, Lisandro Gonzalez, Landon Brown, Apeksha Agarwal, Kermit Speeg.
Mucormycosis (zygomycosis) is an invasive fungal disease caused by Rhizopus species, most commonly implicated in diabetic ketoacidosis and other immunocompromised states. This report presents a unique case of colonic mucormycosis in a patient several weeks after liver transplant. The patient’s course was complicated by polymicrobial infection and intra-abdominal abscesses, ultimately leading to septic shock and death. This case is the first of its kind to describe such malignant abdominal mucormycosis in a solid organ transplant recipient.
Mucormycosis is an invasive fungal infection caused by Rhizopus species, most classically seen in diabetic ketoacidosis, which typically causes rhino-orbital disease but can also cause significant pulmonary disease.1Rhizopus spores are inhaled, transported to the pharynx, and eventually cleared by the gastrointestinal tract.2 However, intravenous catheters, burn wounds, pressure dressings, and even minor breaks in the skin have been implicated as potential sources of entry for this pathogen.1 In addition to patients with diabetes mellitus, hematopoietic and solid organ transplant recipients are at a significant risk of infection with Rhizopus. Although the exact figures are unknown, incidence of invasive mucormycosis is estimated to be less than 5% in solid organ transplant recipients.3 This case describes a unique case of invasive gastrointestinal mucormycosis causing septic shock after liver transplant.
A 70-year-old-man with cirrhosis secondary to nonalcoholic steatohepatitis complicated by hepatocellular carcinoma presented for an orthotopic liver transplant with a model for end-stage liver disease score of 12. After transplant, the patient was started on tacrolimus, mycophenolate mofetil, and methylprednisolone for immunosuppression. No T-cell depleting agents nor interleukin receptor antagonists were administered in the induction of his immunosuppression. In addition, the patient was started on piperacillin-tazobactam, valacyclovir, and fluconazole empirically for bacterial, viral, and fungal prophylaxis, respectively. Three weeks postoperatively, gastroenterology was consulted for multiple episodes of melena and hematochezia causing acute blood loss anemia, requiring several transfusions of packed red blood cells. The patient’s upper endoscopy was unrevealing for a source of bleeding. Colonoscopy showed a large, inflammatory mass with cratering ulceration approximately 25 cm from the anal verge (Figure 1). Although no active bleeding was identified, nor any intervention performed, the mucosa was extremely friable and undoubtedly the source of the patient’s hematochezia. Biopsy of the mass showed necrotic, inflammatory debris with hyphal fungal elements consistent with mucormycosis (Figure 2). There was no evidence of rhino-orbital disease nor diabetic ketoacidosis. On thoracic computed tomography, the patient was found to have bilateral airspace opacities consistent with aspiration pneumonia and a small right-sided pleural effusion. Pleural fluid studies and respiratory cultures were unremarkable for fungi and only grew Klebsiella pneumoniae. Bacterial and fungal blood cultures were unremarkable. The patient was subsequently started on acyclovir and amphotericin after an infectious disease consultation.
This case uniquely describes the potential morbidity and mortality of an unlikely pathogen manifesting in an extremely rare manner. Because solid organ transplant has become increasingly common over the past several decades, the incidence of systemic mycoses has risen as well. Although the exact figure is difficult to measure and likely under-represented because of the lack of formal reporting systems, the incidence of fungal infections in critically ill patients has been estimated at up to 10%.4 Of the invasive fungal infections, Candida and Aspergillus species are most commonly implicated. Gastrointestinal zygomycosis is exceedingly rare and is estimated to have a mortality of up to 50% of cases.5 This case adds to a growing body of literature that highlights the morbidity and mortality of mucormycosis infection of the gastrointestinal tract.
Author contributions: P. Aggarwal and H. Patel wrote the manuscript and reviewed the literature. L. Gonzalez, L. Brown, and K. Speeg revised the manuscript for intellectual content. A. Agarwal provided histopathology images. K. is the manuscript guarantor.