Patient education: Microscopic colitis (The Basics)

What is microscopic colitis? — 

This is a condition that causes watery diarrhea. It involves the colon, which is another name for the large intestine (figure 1). There are several types of microscopic colitis, including "lymphocytic colitis" and "collagenous colitis." These types cause the same symptoms and are treated the same way.

Microscopic colitis happens when the colon gets inflamed. But doctors don't always know what makes the colon inflamed. In some cases, it seems to be related to use of certain medicines, such as nonsteroidal antiinflammatory drugs ("NSAIDs").

Microscopic colitis happens most often in adults. Although the symptoms are bothersome, the condition is not life-threatening. It does not lead to serious problems, like cancer.

What are the symptoms of microscopic colitis? — 

Microscopic colitis causes episodes of diarrhea that is watery and not bloody. Most people have 4 or more watery bowel movements a day. Diarrhea can last weeks to months.

People sometimes have other symptoms, too. These often include weight loss, belly pain, or feeling very tired.

Is there a test for microscopic colitis? — 

Yes. Your doctor or nurse will do an exam and order different tests to exclude other causes of diarrhea and diagnose microscopic colitis. These can include:

●Blood tests

●Lab tests on a sample of bowel movement

●Colonoscopy or sigmoidoscopy – These are procedures that let the doctor look at the inside of your colon. They put a thin tube with a camera and light on the end into your anus and up into your rectum and colon (figure 2).

During this procedure, the doctor will also do a test called a biopsy. This involves taking small samples of tissue from your colon. Then, another doctor looks at the samples under a microscope to check for microscopic colitis. A biopsy is the only test that can tell for sure if you have microscopic colitis.

How is microscopic colitis treated? — 

Treatment depends on your individual situation. It usually involves 1 or more of these:

●Medicine changes – If your doctor thinks a medicine is related to your symptoms, they will recommend you stop taking it.

●Anti-diarrhea medicines – These reduce the number of bowel movements you have. An example is loperamide (brand name: Imodium).

●Steroid medicine called budesonide (brand name: Entocort) – This helps reduce inflammation in the colon.

If these treatments don't help enough to ease your symptoms, tell your doctor or nurse. There are other medicines or treatments that might help.

Some people need treatment for a long time. That's because symptoms sometimes come back after stopping treatment.

More on this topic

Patient education: Diarrhea in teens and adults (The Basics)
Patient education: Colitis (The Basics)
Patient education: Celiac disease (The Basics)
Patient education: Nonsteroidal antiinflammatory drugs (NSAIDs) (The Basics)
Patient education: Colonoscopy (The Basics)
Patient education: Sigmoidoscopy (The Basics)

Patient education: Chronic diarrhea in adults (Beyond the Basics)
Patient education: Celiac disease in adults (Beyond the Basics)
Patient education: Nonsteroidal antiinflammatory drugs (NSAIDs) (Beyond the Basics)
Patient education: Colonoscopy (Beyond the Basics)
Patient education: Flexible sigmoidoscopy (Beyond the Basics)