Ulcerative colitis (UC) is a chronic relapsing and remitting inflammatory bowel disease confined to the colon, characterized by rectal bleeding, diarrhea, fecal urgency, and abdominal pain.
The prevalence in Europe and the US is between 1/400-1/200. It is not a rare disease.
Disease onset is most frequently seen in 20-35 year olds, but can occur at any age. Ten to fifteen percent of patients are diagnosed in childhood or adolescence and up to 40% are diagnosed after the age of 40 years. Initial symptoms include bloody diarrhea, passage of mucus, abdominal pain and false urges to have a bowel movement. Severity varies and is classified as mild (<4 stools daily, no signs of toxicity), moderate (>4 stools daily with minimal signs of toxicity), severe (>6 bloody stools daily with evidence of toxicity) or fulminant (>10 bloody stools per day, toxicity, abdominal tenderness and distension). Signs of toxicity include fever, tachycardia, anemia and elevated erythrocyte sedimentation rate. UC generally involves the rectum then extends upwards through the colon to varying degrees. Patients with fulminant UC are at risk for toxic dilation, hemorrhage, perforation and death if untreated. Extraintestinal complications often associated with UC can be ocular (episcleritis, scleritis and uveitis), dermatological (erythema nodosum, pyoderma gangrenosum), hepatic (primary sclerosing cholangitis (PSC)) and psychological (anxiety and depression). Sacroiliitis and ankylosing spondylitis (see this term) are frequently associated with UC. Patients with UC usually have recurrent flare-ups and then periods of remission lasting months or years.
The exact etiology is unknown but it is thought to involve a combination of genetic, immunological and environmental factors. Many genes have been associated with UC susceptibility such as IL23R and MUC3A, genes implicated in mucosal barrier function. At present, 100 susceptibility loci specific to UC have been identified, but this number is rapidly rising.
A stool sample is first analyzed and a blood test is taken to measure levels of white blood cells and platelets, C-reactive protein, erythrocyte sedimentation rate and hemoglobin. A colonoscopy is necessary for diagnosis as it allows for visualization of the colon and identifies mucosal changes characteristic of UC (loss of the typical vascular pattern, granularity, friability, and ulceration). A biopsy is useful in distinguishing UC from other intestinal inflammatory diseases.
Crohn's disease (CD, see this term) needs to be excluded along with Behçet's disease, sarcoïdosis, lymphoma (see these terms) and various parasitic, bacterial or viral infections.
Treatments available depend on the extent of inflammation in the colon. Mild to moderate distal colitis is usually treated with oral aminosalicylates, topical mesalamine or topical corticosteroids. If these treatments are unsuccessful, oral prednisone, infliximab (by IV) or thiopurines can be taken. In many cases of distal colitis, mesalamine enemas are effective in the maintenance of remission. Topical treatments are not an option in mild to moderate extensive colitis and an oral aminosalicylate is usually prescribed first. A colectomy (either with Brooke ileostomy or ileal pouch-anal anastomosis) is a viable option for patients with severe UC resistant to other forms of treatment but it can lead to complications such as pouchitis, cuffitis or CD of the ileoanal pouch. Proper nutrition and management of emotional stress are essential. An annual or biannual colonoscopy with biopsy is recommended due to an increased risk of colon cancer in UC patients.
Unless a colectomy is performed, the disease course is relapsing and remitting.
- Pr Edward LOFTUS