What Is Pseudomembranous Colitis?

Medically Reviewed by Minesh Khatri, MD on February 20, 2024
4 min read

Pseudomembranous colitis (PMC) is inflammation in your colon that happens when there's too much of certain bacteria in your system. The bacterium that causes PMC is Clostridium difficile, or C. diff.

PMC is also called antibiotic-associated colitis or C. difficile colitis. Most of the time, it's a side effect of taking antibiotics.

People in hospitals or nursing homes also can get PMC, especially if they've just had surgery or are receiving treatment for cancer.

Besides taking antibiotics, you're at increased risk if you:

  • Are over age 65
  • Have been in an intensive care unit (ICU)
  • Have burns on your body
  • Have had a C-section or surgeries of the GI tract
  • Have kidney problems
  • Diseases of the colon such as inflammatory bowel disease or colorectal cancer
  • Use chemotherapy drugs
  • Use of drugs called proton-pump inhibitors, which lessen stomach acid
  • Have had a previous C. diff infection

It's rare for young children or infants to get PMC.

It can take a day or two for PMC symptoms to show up after you start taking antibiotics. You may not have symptoms until a week or two after you've finished taking them.

The most common signs are:

See your doctor if you've recently taken antibiotics and have diarrhea. You need medical help any time you have severe diarrhea with stomach cramps or blood or pus in your stool.

In more serious cases of PMC, you may also have:

C. diff lives in soil, air, water, and feces and sometimes in foods like processed meats. You can get it when you touch a surface that has the bacteria on it and then put your hand near or in your mouth. Once it's in your body, C. diff makes a kind of poison.

The good bacteria in your colon usually keep the amount of C. diff in your body under control, but antibiotics can kill the healthy bacteria and let C. diff grow too fast. This damages your colon and causes PMC.

While practically any antibiotic can cause it, some are more likely to cause PMC than others. These include:

PMC also can be related to:

To find out if you have PMC, you may need one of these tests:

  • Blood test to check your white blood cell count
  • Imaging tests, like an X-ray or CT scan of your lower belly (for serious cases)
  • Stool sample test to check for bacteria in your colon

You also may have a colonoscopy or sigmoidoscopy, which are exams that look inside your colon with a thin flexible tube. Your doctor may take a tissue sample during the exam for testing.

Your doctor will prescribe antibiotics that help good bacteria grow back so your symptoms go away faster.

These include:

While receiving an antibiotic, you may also be given bezlotoxumab (Zinplava). Given as a shot in a vein, this medicine helps reduce the recurrence of a C. diff infection.

If your PMC is severe or keeps coming back, you may need:

  • Extra rounds of antibiotics
  • Fecal microbial transplant (FMT), during which your doctor puts healthy stool from a donor into your system to help restore good bacteria
  • Surgery to take out part of your colon (less than 1% of people with PMC need this)

If you're dealing with PMC symptoms, drink plenty of fluids like water or watered-down fruit juice and eat things with more salt such as Saltines. Eat soft foods that are easy to digest like applesauce, rice, or bananas. Avoid high-fiber foods like nuts, beans, and veggies.

Eat several small meals during the day instead of a few large ones, and stay away from fried, spicy, or fatty foods. They can irritate your stomach and make your symptoms worse.

Wash your hands with soap and water regularly to keep C. diff from spreading and getting back into your system. Hand sanitizers do not work in preventing the recurrence of the infection.