When you first experience episodes of diarrhea and cramps, you may simply dismiss the problems as a temporary sign of a sensitive stomach. But if you find that you’re making more frequent trips to the bathroom and you notice a little blood in your stool, it’s time to talk to your doctor about your symptoms. Medical evaluation is the only way to determine if you have ulcerative colitis (UC) or not.

Diagnosing UC is a process of ruling out other disorders and infections that can trigger similar symptoms. Rectal bleeding, which is almost always present in people with UC, is a telltale sign; however there are also a number of infectious diseases that also can cause it.

Your doctor will begin by talking to you about your symptoms and then, step by step, take you through more refined diagnostic tests.

Step 1: Your medical history

Before you go to the doctor, ask your relatives if they know of family members who have been diagnosed with UC.

“If you discover that ulcerative colitis runs in your family, that would make the diagnosis more likely,” says Daniel H. Present, M.D., clinical professor of medicine, gastroenterology, at Mount Sinai Medical Center in New York City.

Your doctor may also ask about recent antibiotic use, which can make you vulnerable to antibioticresistant infections from bacteria such as Clostridium difficile. Over-the-counter pain medications can also cause gastrointestinal bleeding.

Step 2: A physical exam

A physical examination should include inspection of the anal canal to look for signs of inflammation.

Step 3: Stool samples

These are checked for signs of inflammation and infection.

Step 4: Blood tests

"Blood tests can reveal anemia or low electrolytes that could suggest an infection or chronic diarrhea and dehydration," explains Sunanda V. Kane, M.D., associate professor of medicine at the Mayo Clinic in Rochester, MN.

Step 5: Flexible sigmoidoscopy and/or a colonoscopy

"If a patient has rectal bleeding, this mandates that they have either a sigmoidoscopy or colonoscopy," says Dr. Present. "A flexible sigmoidoscopy is the initial procedure of choice because you can do it in the office without [having the patient take laxatives in order to] prepare the bowel for examination."

Sigmoidoscopy is a visual examination of the rectum and lower part of the colon with a thin, lighted tube (endoscope).

A colonoscopy is an examination of the entire colon with a longer endoscope that can view the entire colon. The prep for the exam includes using various agents as laxatives to clear out the bowel. This procedure can pinpoint the extent of the disease.

Step 6: Imaging

Doctors often choose to use a barium enema x-ray, in which the colon is filled with a chalky white solution (barium), and an x-ray is taken to get a more detailed picture of what is going on inside the intestines. They may also use a CT scan—or computed tomography—to assess the small intestine and the colon. It is a scan that uses x-rays to create cross-sectional pictures of the body.

Looking ahead

"We're investigating blood and stool markers that we can obtain noninvasively and that may be able to tell us if there’s inflammation," says Dr. Kane. "But for now, we make a diagnosis based on tissue biopsies, and there is only one way to obtain those: with an endoscope."

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 31 Aug 2010

Last Modified: 04 Sep 2015