Diagnosis of Ulcerative Colitis

How is ulcerative colitis diagnosed?

The diagnosis of ulcerative colitis is suggested by the symptoms of abdominal pain, rectal bleeding, and diarrhea. As there is no gold standard for diagnosis, the ultimate diagnosis relies on a combination of history, endoscopic finding, histologic features, and negative stool studies for infectious agents.

The initial diagnostic workup for ulcerative colitis includes the following:

• A complete blood count is done to check for anemia; thrombocytosis, a high platelet count, is occasionally seen
• Electrolyte studies and renal function tests are done, as chronic diarrhea may be associated with hypokalemia, hypomagnesemia and pre-renal failure.
• Liver function tests are performed to screen for bile duct involvement: primary sclerosing cholangitis.
• X-ray
• Urinalysis
• Stool culture, to rule out parasites and infectious causes.
• Erythrocyte sedimentation rate can be measured, with an elevated sedimentation rate indicating that an inflammatory process is present.
• C-reactive protein can be measured, with an elevated level being another indication of inflammation.

Many tests are used to diagnose ulcerative colitis. A physical exam and medical history are usually the first step.

Blood tests may be done to check for anemia, which could indicate bleeding in the colon or rectum, or they may uncover a high white blood cell count, which is a sign of inflammation somewhere in the body.

A stool sample can also reveal white blood cells, whose presence indicates ulcerative colitis or inflammatory disease. In addition, a stool sample allows the doctor to detect bleeding or infection in the colon or rectum caused by bacteria, a virus, or parasites.

A colonoscopy or sigmoidoscopy are the most accurate methods for making a diagnosis of ulcerative colitis and ruling-out other possible conditions, such as Crohn's disease, diverticular disease, or cancer. For both tests, the doctor inserts an endoscope-a long, flexible, lighted tube connected to a computer and TV monitor-into the anus to see the inside of the colon and rectum. The doctor will be able to see any inflammation, bleeding, or ulcers on the colon wall. During the exam, the doctor may do a biopsy, which involves taking a sample of tissue from the lining of the colon to view with a microscope.

Sometimes x rays such as a barium enema or CT scans are also used to diagnose ulcerative colitis or its complications.

Knowledge of the extent and severity of the colitis is important in choosing among treatment options.