An inflammatory process in the colon affecting 4-6 individuals per 100,000 in the US.
Peak incidence of the disease is at 20-25 years of age.
More common in females than males.
More common in whites than non-whites.
Clinically, the patient may exhibit, diarrhea with or without bleeding, abdominal pain, mirgratory polyarthritis, ankylosing spondylitis, uveitis, erythema nodosum, primary sclerosing cholangitis and carcinoma. In severe acute cases, diarrhea may be associated with electrolyte imbalance and toxic megacolon.
Progressively involves the rectum, entire colon to distal ileum.
Grossly, the colonic mucosa appears red, granular to friable. There may be ulcerations in the mucosa. With severe ulcerations, the remaining non-ulcerated tissue which remains as an island gives a pseudopolypoid appearance to the mucosa. In contrast to the Crohn's disease, there are no skip lesions meaning that there are not areas of the mucosa that appear normal. In addition, in contrast to the Crohn's disease, ulcerative colitis does not result in mucosal thickening or stricture. In some cases, the mucosa becomes atrophic and appears flat.
Microscopically, there are ulcerations in the mucosa as well as acute and chronic inflammation. The polymorphonuclear leukocytes may infiltrate the glands and appear in the glandular lumen (crypt abcesses). In chronic disease, there may be dysplastic changes in the epithelial lining that may lead to development of adenocarcinoma. The risk of developing cancer, depends on the extent, severity and duration of the disease.