Inflammatory bowel disease and Ulcerative colitis Dr Mamlook Elmagraby

Objectives of the lecture: Upon completion of this lecture, students should be able to: Know the two forms of idiopathic inflammatory bowel disease (IBD) Describe Ulcerative Colitis with respect to: clinical features and extra-intestinal manifestations, pathogenesis, pathology (gross and microscopic features), complications (especially adenocarcinoma preceded by dysplasia)

Ulcerative Colitis

Ulcerative Colitis (UC) UC is an ulceroinflammatory disease affecting the colon, which is limited to the mucosa and submucosa UC begins in the rectum and extends proximally in a continuous fashion UC is a systemic disorder in some persons (primary sclerosing cholangitis) The disease may arise at any age, with a peak incidence between ages 20 and 25 years

Ulcerative Colitis (UC) Morphology UC involves the rectum and sigmoid and may involve the entire colon Colonic involvement is continuous from the distal colon In active disease, mucosa shows hyperemia, edema, and granularity with friability and easy bleeding With severe active disease, there is extensive and broad-based ulceration of the mucosa

Colon, chronic ulcerative colitis, colectomy specimen - mucosal surface This large bowel has a diffusely inflamed mucosal surface, extending from the rectum to the cecum. The right colon appears to be less involved

Ulcerative Colitis (UC) Isolated islands of regenerating mucosa bulge upward to create pseudopolyps Exposure of the muscularis propria and neural plexus to fecal material also may lead to toxic megacolon

Toxic megacolon. Complete cessation of colon neuromuscular activity has led to massive dilatation of the colon and black-green discoloration signifying gangrene and impending rupture

Ulcerative Colitis (UC) Microscopical features: The pathologic features of UC are those of mucosal inflammation, ulceration, chronic mucosal damage A diffuse, predominantly mononuclear inflammatory infiltrate in the lamina propria is present Neutrophilic infiltration may produce collections of neutrophils in crypt lumina (crypt abscesses) The most serious complication of ulcerative colitis is the development of colon carcinoma

Colon, chronic ulcerative colitis This image shows an ulcer base with fibrin, capillaries, and inflammatory cells Note the distorted regenerating crypts at the edge of the ulcer Compare the shape of the regenerating crypts with that of the normal crypts

Ulcerative colitis. Microscopic view of the mucosa, showing diffuse active inflammation with crypt abscess and glandular architectural distortion.

Colon, chronic ulcerative colitis The lamina propria shows an increase in acute and chronic inflammatory cells A mucosal crypt is distended by a collection of neutrophils, known as a crypt abscess

Ulcerative Colitis (UC) Clinical Features UC is characterized by chronic inflammation of the mucosa that involves the rectum and extends proximally through the colon   The extent and severity of the colonic inflammation determine prognosis and presentation (insidious versus acute onset)   The typical clinical course of UC is one of chronic intermittent exacerbations followed by periods of remission Most patients exhibit diarrhea, abdominal pain, rectal bleeding, and the passage of mucus per rectum Exacerbation increase in severity of a disease

Ulcerative Colitis (UC) These symptoms may persist for days, weeks, or months before they subside    More than half of patients have mild disease Colectomy cures intestinal disease, but extraintestinal manifestations may persist Anemia commonly occurs and is caused by: Chronic blood loss from the involved colonic mucosa Bone marrow suppression from the inflammatory condition Subside become less severe

Ulcerative Colitis (UC)   Perforation can occur in patients with severe or fulminant colitis, especially in the setting of toxic megacolon Toxic megacolon is characterized by gross dilation of the large bowel associated with fever, abdominal pain, dehydration, bloody diarrhea, tachycardia Perforation a hole in the containing walls of a structure Fulminant Occurring suddenly, rapidly, and with great severity

Distribution of lesions in inflammatory bowel disease Distribution of lesions in inflammatory bowel disease. The distinction between Crohn disease and ulcerative colitis is primarily based on morphology

Macroscopic Microscopic Feature Crohn Disease Ulcerative Colitis Bowel region Ileum ± colon Colon only Distribution Skip lesions Diffuse Stricture Yes Rare Wall appearance Thick Thin Microscopic Inflammation Transmural Limited to mucosa Pseudopolyps Moderate Marked Ulcers Deep, knife-like Superficial, broad-based Lymphoid reaction Fibrosis Mild to none Serositis Granulomas Yes (~35%) No Fistulae/sinuses Features of Crohn Disease and Ulcerative Colitis

Clinical Feature Crohn Disease Ulcerative Colitis Perianal fistula Yes (in colonic disease) No Fat/vitamin malabsorption Yes Malignant potential With colonic involvement Recurrence after surgery Common Toxic megacolon Features That Differ between Crohn Disease and Ulcerative Colitis