S3389 Segmental Colitis Associated With Diverticulosis Mimicking Inflammatory Bowel Diseases

Abstract

INTRODUCTION: Segmental colitis associated with diverticulosis (SCAD) is defined by active chronic inflammation in colonic segments affected by diverticular disease. It was previously thought to be a complication of inflammatory bowel disease (IBD) and was not considered a distinct entity until 1983. We present two cases of SCAD that were initially diagnosed as IBD. CASE DESCRIPTION/METHODS: Case 1: 59-year-old male with presumed left-sided ulcerative colitis presented to us with intermittent hematochezia for months. Physical exam was unremarkable. Laboratory work-up was significant for elevated fecal calprotectin at 1543μg/mg. Colonoscopy revealed moderate sigmoid diverticulosis with surrounding erythema and erosions, but otherwise normal rectum, colon and terminal ileum. Biopsies from the affected sigmoid colon showed moderate active colitis and crypt abscesses. Small bowel imaging was unremarkable. The prior IBD diagnosis was changed to SCAD and the patient started a Mediterranean diet and has remained asymptomatic on follow-up. Case 2: 39-year-old male with a history of sigmoid diverticulosis with associated wall thickening and recurrent episodes of left lower quadrant abdominal pain with non-bloody diarrhea came to our clinic for suspected Crohn’s disease. Physical exam and laboratory workup were unremarkable. A colonoscopy ten years prior revealed sigmoid diverticulosis with associated erythema and edema. Biopsies showed mild active colitis. We repeated a colonoscopy that revealed mild inflammatory changes in the sigmoid colon surrounding the diverticula, but otherwise normal rectum, colon and terminal ileum. Biopsies from the affected sigmoid colon showed lymphoplasmacytic expansion of the lamina propria but no active colitis. Small bowel imaging was unremarkable. The prior IBD diagnosis was changed to SCAD and the patient started a Mediterranean diet and has remained asymptomatic on follow-up. DISCUSSION: These two cases highlight the importance of accurately diagnosing SCAD as it impacts the disease management and prognosis. SCAD and IBD share many overlapping features; however, SCAD typically spares the rectum and the diverticular orifices, and has a lower rate of relapse.SCAD can be classified into four different types (A, B, C, and D) based on presentation pattern, endoscopic and pathologic features. There is limited data informing management of patients with SCAD; current treatment options include diet, mesalamines, antibiotics, steroids, probiotics and in some cases anti-TNF therapy or surgery.Figure 1.: Patchy erythema and erosions in the sigmoid colon near diverticula.Figure 2.: Mild patchy erythema in the sigmoid colon near diverticula.