The Common Vein Copyright 2008
Ulcerative colitis is a chronic relapsing ulceroinflammatory condition of the large bowel with acute and subacute manifestations. The cause of the disease is mostly unknown, but it does appear to be an exaggerated immune response to local flora. In some cases it does have a genetic predisposition . It results in diarrhea, which may have blood and mucus in it.
It is characterized by relapsing nature, its involvement of the colon and almost universal involvement of the rectum,
Structurally it is characterised by its involvement of the mucosa and submucosa and as stated above by almost universal involvement of the rectum. The mucosa is inflammed and ulcerated. In severe cases the inflammation mayt spread to deeper layers.
The disease starts in the rectum and progresses in a retrograde fashion. Pancolitis is seen in more severe casses. If the ileum is involved it is usually only the distal ileum, and usually within 25cms. The involvement of the ileum is thought to be from a backwash phenomenon and is called “backwash ileitis”.
Functionally, in the more severe cases, there is loss of mucosal function and water is not reabsorbed and lost in the form of diarrhea.
Pathologically the inflammatory process may be mild with minimal redness and granularity of the mucosa, but in severe cases there may be severe ulceration and pseudopolyp formation.
Associated systemic diseases such as sclerosing cholangitis and biliary cirrhosis and other HLA B-27 related disease may occur, but the most foreboding disease is carcinoma of the colon. About 5 percent of people with ulcerative colitis develop colon cancer. It appears to be related to the duration of the colitis, the severity and the age of onset. Toxic megacolon is another acute life threatening associated disease that msy complicate UC.
The diagnosis is suspected clinically in the patient who presents with recurrent attacks of acute bloody and mucusy diarrhea, and who is shown to have inflammatory disease of the rectum and maybe the distal colon without skip areas. The diagnosis is confirmed by biopsy revealing a mucosal inflammatory process, without granulomas, the presence of cryptitis and crypt abscesses.
The presence of fecal leukocytes is diagnostic for inflammatory diarrhea. Negative stool cultures and absence of C. difficile toxin, exclude many acute infectious causes of diarrhea. A positive p-ANCA test is highly suggestive of ulcerative colitis.
Differential diagnosis includes Crohn’s disease, Campylobacter, Yersinia, amebiasis, and ischemic colitis.
The approach to treatment is two fold and is initially medical. Firstly to get the patient into remission and secondly to maintain the patient in remission.
Aminosalicylates that contain 5-aminosalicylic acid are first line remission agents. Prednisone may be needed initially as well. A combination of oral and intermittent rectal mesalamine is the first line for maintemnnace in patients with mild to moderate disease.
Surgey is indicated for failed medical therapy, impending toxic megacolon, and dysplasia on follow up colonoscopic biopsy.
The annual rate of colorectal cancer is about 2% after 20 years of disease and 8% after 30 years. (Lashner) recommendations include the surveillance for colorectal cancer imnitiated after 10 years of disease. Colonoscopy with random biopsy every 10cms is recommended every 2 years. In the presence of any microscopic evidence of dysplasia prophylactic colectomy is recommended.