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Persistent, watery diarrhea could be a sign of microscopic colitis. Find out about testing and treatment for this inflammatory disorder of the colon.
Microscopic colitis is an inflammation of the large intestine (colon) that causes persistent watery diarrhea. The disorder gets its name from the fact that it's necessary to examine colon tissue under a microscope to identify it, since the tissue may appear normal with a colonoscopy or flexible sigmoidoscopy.
There are different subtypes of microscopic colitis:
Researchers believe collagenous (kuh-LAYJ-uh-nus) colitis and lymphocytic colitis may be different phases of the same condition. Symptoms, testing and treatment are the same for all subtypes.
The colon is a long tubelike organ in the abdomen. It's the longest part of the large intestine. The colon carries waste to be expelled from the body. The rectum makes up the last several inches of the colon.
Signs and symptoms of microscopic colitis include:
The symptoms of microscopic colitis can come and go frequently. Sometimes the symptoms resolve on their own.
If you have watery diarrhea that lasts more than a few days, contact your doctor so that your condition can be diagnosed and properly treated.
It's not clear what causes the inflammation of the colon found in microscopic colitis. Researchers believe that the causes may include:
Risk factors for microscopic colitis include:
Some research studies indicate that using certain medications may increase your risk of microscopic colitis. But not all studies agree.
Medications that may be linked to the condition include:
Most people are successfully treated for microscopic colitis. The condition does not increase your risk of colon cancer.
A complete medical history and physical examination can help determine whether other conditions, such as celiac disease, may be contributing to your diarrhea.
Your doctor will also ask about any medications you are taking — particularly aspirin, ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve), proton pump inhibitors, and selective serotonin reuptake inhibitors (SSRIs) — which may increase your risk of microscopic colitis.
To help confirm a diagnosis of microscopic colitis, you may have one or more of the following tests and procedures:
Flexible sigmoidoscopy. This procedure is similar to a colonoscopy, but rather than viewing the entire colon, a flexible sigmoidoscopy allows your doctor to view the inside of the rectum and most of the sigmoid colon — about the last 2 feet (61 centimeters) of the large intestine.
The doctor uses a slender, flexible, lighted tube (sigmoidoscope) to examine the intestinal lining. A tissue sample can be taken through the scope during the exam.
Because intestinal issues often appear normal in microscopic colitis, a definite diagnosis of microscopic colitis requires a colon tissue sample (biopsy) obtained during a colonoscopy or flexible sigmoidoscopy. In both subtypes of microscopic colitis, cells in colon tissue have a distinct appearance under the microscope, so the diagnosis is definite.
In addition to a colonoscopy or flexible sigmoidoscopy, you may have one or more of these tests to rule out other causes for your symptoms.
During a flexible sigmoidoscopy, the provider inserts a sigmoidoscope into your rectum to check for abnormalities in your lower colon.
Microscopic colitis may get better on its own. But when symptoms persist or are severe, you may need treatment to relieve them. Doctors usually try a stepwise approach, starting with the simplest, most easily tolerated treatments.
Treatment usually begins with changes to your diet and medications that may help relieve persistent diarrhea. Your doctor may recommend that you:
If signs and symptoms persist, your doctor may recommend:
When the symptoms of microscopic colitis are severe, and medications aren't effective, your doctor may recommend surgery to remove all or part of your colon. Surgery is rarely needed to treat microscopic colitis.
Changes to your diet may help relieve diarrhea that you experience with microscopic colitis. Try to:
Here's some information to help you get ready for your appointment and know what to expect from your doctor.
Some basic questions to ask your doctor include:
Don't hesitate to ask questions anytime you don't understand something.
Be ready to answer questions your doctor is likely to ask you:
You may find some relief from persistent diarrhea by making changes to your diet: