Abstract: PUB241
When Timing Misleads: Late-Onset Sirolimus-Induced Colitis in a Kidney Transplant Recipient
Session Information
Category: Transplantation
- 2002 Transplantation: Clinical
Authors
- Mecadon, Krista, Brown University Health, Providence, Rhode Island, United States
- Patel, Pooja V., Brown University Health, Providence, Rhode Island, United States
- Merhi, Basma Omar, Brown University Health, Providence, Rhode Island, United States
Introduction
Sirolimus-associated gastrointestinal toxicity is a well-recognized yet underdiagnosed cause of noninfectious colitis in solid organ transplant recipients. We present a rare case of late onset sirolimus-induced colitis occurring nine years after kidney transplantation.
Case Description
42-year-old male with end stage renal disease secondary to hypertension underwent deceased donor kidney transplant. While maintained on prednisone, tacrolimus, and azathioprine, he developed suboptimal allograft function with serum creatinine of 3.4 mg/dL. A diagnostic allograft biopsy revealed acute tubular necrosis and donor-derived interstitial fibrosis and tubular atrophy, prompting conversion from tacrolimus to sirolimus. Nine years later, he develops severe abdominal pain and diarrhea. CT scan abdomen and pelvis showed proctocolitis without bowel obstruction or perforation. Infectious stool extended PCR, stool ova and parasite, cytomegalovirus (CMV) PCR and tissue transglutaminase IgA were negative. Colonoscopy showed segmental moderate colitis in the descending and sigmoid colon and rectum. Treatment with higher doses of prednisone resulted in no clinical improvement. A repeat colonoscopy showed proctosigmoiditis. Histopathology showed focal active colitis without increased intraepithelial lymphocytes and subepithelial collagen band to indicate microscopic colitis, no chronicity to suggest inflammatory bowel disease (IBD) and no histologic feature of graft-versus-host disease. Stains were negative for infectious causes. Given the negative extensive work-up, sirolimus-induced colitis was suspected. Sirolimus was discontinued, and the patient was transitioned back to tacrolimus. Within a few weeks of sirolimus withdrawal, his symptoms markedly improved with complete resolution of abdominal pain and diarrhea.
Discussion
Sirolimus-induced colitis is mostly reported within the first year of therapy; however, late-onset presentations are rare and may delay diagnosis. Endoscopic findings are nonspecific and may mimic IBD or infectious colitis with symptoms frequently refractory to corticosteroids. Clinical improvement after sirolimus discontinuation is both diagnostic and therapeutic. Awareness of late-onset sirolimus-induced colitis is critical, highlighting the importance of considering medication toxicity in transplant recipients with unexplained abdominal pain and diarrhea.