Mycophenolate Mofetil-Induced Segmental Colitis Mimicking Ischemic Colitis
A 64-year-old gentleman with a history of autoimmune autonomic dysfunction and gastroparesis on a background of type 2 insulin-dependent diabetes mellitus presented to our hospital with abdominal pain and diarrhea. He did not have any history of coronary artery disease or other cardiovascular comorbidities. The patient was initially started on MMF 1,000 mg twice daily 2 years prior for autoimmune autonomic dysfunction. This was subsequently raised to 1,500 mg twice daily 4 months preceding the patient's presentation. The diarrhea had started 2 months prior to presentation, with up to eight episodes of non-bloody diarrhea per day. Abdominal pain was of recent onset with a 4-day history of lower abdominal stabbing pain most severe in the left lower quadrant and reported as constant and progressive in nature. He also had decreased appetite, weight loss, sensation of bloating and intermittent nausea. He did not have any history of coronary artery disease or other cardiovascular comorbidities. The patient had undergone esophagogastroduodenoscopy within the past year, which had been unremarkable. A colonoscopy 5 years prior had shown diverticulosis, but otherwise been normal.\nOn examination, his vital signs were normal, and he had diffuse abdominal tenderness with increased intensity in the left lower quadrant area. Initial investigations revealed an elevated white blood cell count of 17.9 × 109 cells/l (normal 3.5–10.5 × 109 cells/l) with normal hemoglobin and platelet count. An elevated creatinine of 1.8 mg/dl (normal 0.6–1.2 mg/dl) was also noted. Abdominal X-ray showed no obstruction. Stool examination for microbiology including Clostridium difficile was negative. Initial management included hydration with intravenous fluids, empiric antibiotics and analgesia. Further work-up with CT of the abdomen and pelvis with contrast revealed segmental wall thickening and pericolic inflammation at the splenic flexure and proximal descending colon without evidence of diverticulitis. Flexible sigmoidoscopy revealed a segmental erythematous mucosa and multiple ulcers in the sigmoid colon, descending colon, splenic flexure and proximal transverse colon, suggesting a mucosal injury pattern consistent with ischemic colitis (fig. ). However, biopsies showed dilated damaged crypts, eosinophilic epithelial changes and crypt abscesses with apoptotic bodies, a pattern of injury highly suggestive of MMF-related colitis (fig. ). There was no evidence of cytomegalovirus infection.\nMMF therapy was subsequently discontinued and the patient was discharged following improvement of symptoms with follow-up in an outpatient clinic 5 weeks later. During this visit, his abdominal pain and diarrhea had improved rapidly and significantly. He is scheduled for a repeat colonoscopy in 4 months’ time to assess the extent of mucosa recovery.