Diagnosis and classification of ulcerative colitis.

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease (IBD) characterised by superficial mucosal ulceration, rectal bleeding, diarrhoea, and abdominal pain. In contrast to Crohn's disease (CrD), UC is restricted to the colon and the inflammation is limited to the mucosal layer. Classic UC affects the colon in a retrograde and continuous fashion starting from the rectum and extending proximally. Dependent on the anatomic extent of involvement, UC can be classified as proctitis, left-sided colitis, or pancolitis. Inflammatory arthropathies and primary sclerosing cholangitis (PSC) are the most common and clinically most important extraintestinal manifestations of UC. The aetiopathogenesis of UC is incompletely understood, but immune-mediated mechanisms are responsible for dysregulated immune responses against intraluminal antigens in genetically predisposed individuals. The diagnosis is based on the history, as well as clinical, radiological, endoscopic and histological features. Autoantibodies, mainly antineutrophil cytoplasmic antibodies (ANCA) and anti-goblet cell antibodies (GAB) may be helpful in the early diagnosis of UC and in differentiating it from CrD.