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PROGRESSION OF DIVERTICULAR COLITIS TO CLASSICAL ULCERATIVE COLITIS
S Missiha, G Gardiner, C Ottaway
Diverticular colitis refers to the presence of chronic mucosal inflammation of sigmoid colon affected by diverticular disease. While the disease shares many similarities with inflammatory bowel disease (IBD), it has distinguishing features both clinically and pathologically. The natural history of diverticular colitis is poorly understood and reported cases of subsequent development of ulcerative colitis after an initial diagnosis of diverticular colitis are rare – only nine cases have been reported. We report two additional cases and briefly review the relevant literature.
Case 1: A 79 year-old woman with a history of osteoarthritis and osteoporosis was initially referred for hematochezia. Subsequent endoscopy confirmed a segmental colitis confined to a region of dense sigmoid diverticulosis. Biopsies from the area showed acute and chronic inflammation, while biopsies from elsewhere in her colon and terminal ileum were unremarkable. She was diagnosed with diverticular colitis and treated with oral mesalamine 2 grams daily. Her symptoms resolved and she remained well for several years until she presented with bloody diarrhea and abdominal discomfort. She had elevated inflammatory markers and stool pathogens were negative. A sigmoidoscopy showed continuous proctosigmoiditis beyond the region of diverticulosis. Biopsies were consistent with ulcerative colitis.
Case 2: A previously well 56 year-old man presenting with intermittent hematochezia had a colonoscopy which revealed a 20 cm area of segmental inflammation and ulceration in a region of extensive diverticuli with rectal sparing. The remainder of the colon was endoscopically and histologically normal. He responded partially to oral mesalamine 4 grams daily and daily budesonide enemas. 2 years later, after tapering off of mesalamine, he experience an exacerbation characterized by bloody diarrhea 3 times daily. No pathogens were identified from stool. A colonoscopy revealed continuous active inflammation of the rectum and sigmoid colon to 35 cm with typical endoscopic appearances of ulcerative colitis. Biopsies were consistent with this diagnosis. He responded well to reinstitution of mesalamine enemas 4 grams daily.
CONCLUSIONS: The progression from diverticular colitis to frank ulcerative colitis suggests either a common pathogenesis or that the former predisposes to the later. Further investigation of this under-reported clinical entity and it’s relationship to ulcerative colitis is warranted.