Diverticular Disease-Related Colitis
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Diverticular Disease-Related Colitis KEY FACTS Colon TERMINOLOGY ○ Abscess, fistula, perforation • Segmental colitis-associated diverticulosis (SCAD) ○ Exception is Crohn disease-like variant of SCAD that may show mural lymphoid aggregates ETIOLOGY/PATHOGENESIS MICROSCOPIC • Unknown, TNF-α may play role • Chronic colitis-like changes mimicking inflammatory bowel CLINICAL ISSUES disease • Presents with hematochezia, abdominal pain, diarrhea • Ulcerative colitis-like variant shows changes confined to • Median age: 64 years mucosa ○ Range: 40-86 years ○ Diverticulitis may or may not be present in these cases • Predominately involves descending and sigmoid colon (with • Crohn disease-like variant shows mural lymphoid rectal sparing) aggregates • Treatment directed toward diverticular disease suppresses • Changes in both variants confined to segment involved symptoms with diverticulosis coli MACROSCOPIC TOP DIFFERENTIAL DIAGNOSES • Mucosal changes are mild and nonspecific • Ulcerative colitis, Crohn disease, infectious colitis, diversion • Mural changes are related more to underlying diverticulosis colitis, NSAID-associated colitis coli rather than SCAD Diverticular Disease-Associated Colitis Diverticular Disease-Associated Colitis (Left) The mucosa surrounding the openings of diverticula ſt into the colonic lumen is erythematous and granular, consistent with diverticular disease-associated colitis (DDAC) . (Right) It is not uncommon to find some inflammation or erosions around the luminal opening of a colonic diverticulum ſt. To be diagnostic of DDAC, inflammation must involve the mucosa in the interdiverticular region . Chronic Active Colitis Basal Lymphoplasmacytosis (Left) A chronic colitis pattern of inflammatory infiltrate is seen in both the ulcerative colitis-like and Crohn disease- like variant of DDAC. The mucosal changes are indistinguishable from true inflammatory bowel disease (IBD). (Right) A band of lymphoplasmacytic infiltrate is present beneath the base of the crypts in the mucosa. The distinction between DDAC and true IBD can only be made by knowing the distribution of disease involvement. 426 Diverticular Disease-Related Colitis Colon TERMINOLOGY Natural History • Clinical course is related to severity of disease Abbreviations • Endoscopic disease severity scoring system has been • Diverticular disease-associated colitis (DDAC) proposed Synonyms • Mild cases may not need any intervention, other than follow-up colonoscopy • Segmental colitis associated with diverticulosis (SCAD) • Severe cases or patients with continued symptoms treated Definitions with antiinflammatory medications or steroids • Chronic colitis involving interdiverticular mucosa in colonic • Resection restricted to patients with severe symptoms segment with diverticulosis unresponsive to medical therapy ○ Histologic findings may mimic ulcerative colitis or Crohn Treatment disease • Options, risks, complications ETIOLOGY/PATHOGENESIS ○ Treatment directed toward diverticular disease may suppress symptoms Exact Pathogenetic Mechanism Unknown – Decrease intraluminal pressure by increasing stool • Immune-mediated injury may play role bulk (high-fiber diet) – Surgical intervention usually dictated by severity of Immunologically Mediated diverticulosis rather than SCAD • Stasis of colonic contents may promote bacterial • Drugs proliferation that acts as trigger for mucosal inflammation ○ Antibiotics for treatment of active diverticulitis • Disproportionate immune response in genetically ○ Oral aminosalicylates and probiotics for mild SCAD susceptible host ○ Immunosuppressives for severe SCAD • Similar to inflammatory bowel disease (IBD), TNF-α has – Sulfasalazine been postulated to play role in pathogenesis of SCAD – 5-aminosalicylic acid May Be Related to Severity of Diverticulitis – Topical steroids • Early mucosal inflammation around opening of diverticula Prognosis into lumen, which then spreads to interdiverticular mucosa • Depends on patient symptoms, severity of disease, and CLINICAL ISSUES response to medical intervention Epidemiology IMAGING • Incidence CT Findings ○ Estimated: ~ 0.36% • Colonic wall thickening in segment involved with • Age diverticulosis and associated luminal narrowing ○ Median: 64 years (range: 40-86 years) • Diverticular abscess, fistula, or perforation may be seen ○ Later age of onset compared to patients with IBD • Sex MACROSCOPIC ○ Equal incidence in both sexes • Ethnicity General Features ○ Geographical differences are related to differences in • Findings related to diverticulosis coli prevalence of diverticulosis coli, which is higher in West ○ Ostia or openings of diverticula on mucosal surface ○ Sac-like outpouchings ± fecaliths Site ○ Peridiverticular abscesses may be present • Most common in sigmoid colon; rare in other segments ○ Bowel wall thickening or perforation depending on • Rectum is typically spared severity of disease Presentation • Findings related to SCAD • Hematochezia ○ Mucosal erythema or granularity involving interdiverticular segments of colonic mucosal surface • Crampy, abdominal pain ○ Erosions or ulcers in severe cases • Diarrhea • Fistula tract formation and intestinal obstruction may be MICROSCOPIC present in cases associated with severe diverticulitis Histologic Features Endoscopic Findings • Chronic colitis-like mucosal changes mimicking IBD • Changes confined to segment involved with diverticulosis ○ Basal lymphoplasmacytosis coli ○ Crypt architectural disarray ○ Colonic mucosa proximal and distal to diverticular segment is normal ○ Paneth cell metaplasia • Patchy areas of erythema or exudate or diffuse mucosal ○ Variable active inflammation with erosion or ulcer granularity • Mucosal and mural changes confined to segment involved with diverticulosis coli; other parts of colon are normal 427 Diverticular Disease-Related Colitis • 2 variants described DIAGNOSTIC CHECKLIST Colon ○ Ulcerative colitis-like variant – Changes confined to mucosa similar to what is seen in Clinically Relevant Pathologic Features ulcerative colitis • Endoscopic and pathologic findings limited to segment – Prominent basal lymphoid aggregates may be seen involved with diverticulosis coli similar to diversion colitis Pathologic Interpretation Pearls – Crypt rupture reaction may be seen ○ Crohn disease-like variant • Inflammation within diverticulum ("diverticulitis") is not – Best thought of as Crohn-like diverticulitis than form considered SCAD of IBD • SCAD is defined by inflammation of flat mucosa between – Seen in resection specimens openings of diverticula (interdiverticular region) into colonic lumen – Mural lymphoid aggregates mimicking Crohn disease present in segment involved with diverticulitis • Inflammation in SCAD shows chronic colitis pattern similar to IBD – Noncaseating granulomas may be present, ± foreign body giant cell reaction SELECTED REFERENCES – Important not to diagnose this as Crohn disease in older patient with no previous history of IBD 1. Kucejko RJ et al: Considerations and changes in the evaluation, management, and outcomes in the management of diverticular disease: the Predominant Pattern/Injury Type diagnosis, pathology, and treatment of diverticular colitis. Clin Colon Rectal Surg. 31(4):221-5, 2018 • Inflammatory, chronic 2. Mann NS et al: Segmental colitis associated with diverticulosis: systematic evaluation of 486 cases with meta-analysis. Hepatogastroenterology. DIFFERENTIAL DIAGNOSIS 59(119):2119-21, 2012 3. Tursi A et al: Segmental colitis associated with diverticulosis: a 5-year follow- Ulcerative Colitis up. Int J Colorectal Dis. 27(2):179-85, 2012 4. Tursi A: Segmental colitis associated with diverticulosis: complication of • Key to diagnosis is recognizing that colitis in SCAD involves diverticular disease or autonomous entity? Dig Dis Sci. 56(1):27-34, 2011 only segment with diverticulosis 5. Tursi A et al: The endoscopic spectrum of segmental colitis associated with • Inflammation above or below segment involved with diverticulosis. Colorectal Dis. 12(5):464-70, 2010 6. Mulhall AM et al: Diverticular disease associated with inflammatory bowel diverticulosis coli suggests infection or IBD as underlying disease-like colitis: a systematic review. Dis Colon Rectum. 52(6):1072-9, etiology 2009 • Rectum is almost always spared in SCAD but involved in 7. Freeman HJ: Natural history and long-term clinical behavior of segmental ulcerative colitis colitis associated with diverticulosis (SCAD syndrome). Dig Dis Sci. 53(9):2452-7, 2008 Crohn Disease 8. Ierardi E et al: Tumour necrosis factor alpha in segmental colitis associated with diverticula. Dig Dis Sci. 53(7):1865-8, 2008 • Also patchy segmental colitis like SCAD 9. Lamps LW et al: Diverticular disease-associated segmental colitis. Clin • Diagnosis of Crohn disease in segment involved with Gastroenterol Hepatol. 5(1):27-31, 2007 diverticulosis coli should be made with great caution 10. Imperiali G et al: Segmental colitis associated with diverticula: a 7-year follow- up study. Endoscopy. 38(6):610-2, 2006 ○ Clinical or radiographic evidence of disease involvement 11. Sultan K et al: The nature of inflammatory bowel disease in patients with beyond diverticular segment favors Crohn disease coexistent colonic diverticulosis. J Clin Gastroenterol. 40(4):317-21, 2006 ○ Terminal ileal or upper GI involvement favors Crohn 12. Koutroubakis IE et al: The spectrum of segmental colitis associated with disease diverticulosis. Int J Colorectal Dis. 20(1):28-32, 2005 13. Peppercorn MA: The overlap of inflammatory bowel disease