<prompt> True about Crohn;s disease -Continous involvementSinus fistulaMesenteric lymphadenitisStud ulcer  <response>: Ans. is b i.e., Sinus fistula Features Ulcerative coliits Crohns ds o Rectal involvement o Distribution of lesions o Mucosal appearance o Associated ileal o Perianal abscess, fistulas o intestinal strictures obstruction o Intestinal fistulas o Fissures Radiological o Toxic megacolon o Extraintestinai Manifestation - Sclerosing pericholangitis Uveitis Arbritis Pyoderma gangrenosum 90 Continuous Friable, diffusely involved 10, mild, terminal ileal inflammation Rare Not seen Not seen Not seen Rare but more than crohns ds Common Common Common Rectum spared in 50 Skip lesions Cobblestone Appearance 50 have combined ilead and colonic involvement Common Common Common Very rare Rare Common Rare Pathological Features o Depth of inflammation o Creeping mesentric fat o Fibrous thickening of wall o Pseudopolyps o Granulomas o Dysplasia o Carcinoma Mucosal Not seen Not seen Common Not seen Common 10 Transmural Common Common lead pipe Rare Common Rare Rare o Stud ulcers or Collar studbutton ulcers are seen in ulcerative colitis. 