Pseudomembranous Colitis

Pseudomembranous colitis is an inflammatory process that occurs when your colon lining is being injured. Plaques called “pseudomembranes” develop at the site of the injury.


What is pseudomembranous colitis?

Pseudomembranous colitis (PMC) is a severe form of colitis. In this condition, something attacks and injures your colon lining (mucosa). It might be bacteria, toxins or another illness. Your colon mucosa develops thickened, scab-like plaques over the wounds. Your healthcare provider might call these “pseudomembranes.”

What are pseudomembranes?

Pseudomembranes develop on mucous membranes, like your colon lining, when cells die. Your immune system sends white blood cells to the site of the injury. Leftover cellular debris combines with white blood cells called neutrophils to form pseudomembranes. They’re raised areas on the mucosa, up to 2 centimeters (cm) wide, with a yellow-white color.


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Symptoms and Causes

What are the symptoms of pseudomembranous colitis?

Pseudomembranous colitis symptoms include:

You might notice some bleeding or pus in your poop, but not always.

What causes pseudomembranous colitis?

C. diff (Clostridioides difficile) infection is the most common cause of pseudomembranous colitis. C. diff is a bacterial infection that produces toxins that injure your colon lining. About 10% of C. diff infections progress to pseudomembranous colitis. This produces more than 90% of all cases. But other causes of colitis can also cause similar damage.

How does C. difficile cause pseudomembranous colitis?

C. difficile produces toxins that injure your colon mucosa, causing cell death. C. diff infection also can become unusually severe, unusually fast. C. diff infection usually happens after you’ve taken antibiotics. Antibiotics reduce the other bacteria in your gut, but they don’t affect C. diff. This allows C. diff to quickly grow out of control.

Which antibiotics cause pseudomembranous colitis?

Any antibiotic that kills the other helpful bacteria in your gut, but not C. diff, can make you vulnerable to a C. diff infection and pseudomembranous colitis. But some are considered higher risk. They include:

What are other causes of pseudomembranous colitis?

Other causes of colitis can also lead to pseudomembranous colitis, including:

In these cases, colitis is more severe or more complicated than usual. Complications can include reduced blood flow to your colon mucosa (ischemia), which can lead to tissue death and pseudomembranes. Preexisting conditions like inflammatory bowel disease (IBD) may also make your colon more vulnerable.

What are the risk factors for developing pseudomembranous colitis?

You’re more likely to develop pseudomembranous colitis if you:

  • Are in a hospital.
  • Recently took antibiotics.
  • Recently had surgery.
  • Are in a nursing home.
  • Are older than 65.
  • Have an autoimmune disease.
  • Have a weakened immune system.
  • Have had C. diff infection before.

What are the possible complications of pseudomembranous colitis?

When colitis becomes severe and difficult to control, as pseudomembranous colitis can be, it can lead to additional complications, some of which are life-threatening. Complications can include:

  • Dehydration and electrolyte losses. Severe pseudomembranous colitis can cause severe diarrhea, between 10 and 15 times a day. You may not be able to drink enough fluids or keep them in your body long enough to stay hydrated. Severe fluid and electrolyte losses can have dangerous side effects, including low blood volume, low blood pressure and kidney failure.
  • Fluid leakage. Your damaged colon lining may begin to leak fluids into your abdominal cavity (ascites), causing it to swell. You may also lose proteins from your colon, such as albumin. Low albumin can cause your blood vessels to leak, causing edema (swelling in your hands and feet).
  • Toxic megacolon. Uncontrolled severe colitis can cause such severe swelling that it disables your colon. First, the muscles stop moving, causing a blockage. As your colon continues to dilate, it can leak or even tear, spreading infection into your abdominal cavity (peritonitis).
  • Gastrointestinal perforation. Your colon wall can get a hole or tear without toxic megacolon, too. It can happen if you have ulcers in your colon that wear all the way through the wall, or if you have significant necrosis (tissue death) in your colon wall. When bacteria from your colon leak into your abdomen (peritonitis), they can spread to your bloodstream (septicemia).
  • Sepsis. Septicemia can lead to sepsis — a life-threatening, whole-body reaction to severe infection. Sepsis can lead to septic shock, which can cause multiple organ failure and death.

Diagnosis and Tests

How is pseudomembranous colitis diagnosed?

A healthcare provider will listen to your symptoms and ask you questions about your health history. They might order various tests to look for the cause of your symptoms, including blood tests, imaging tests and poop tests. They’ll look for signs of infection or inflammation and other red flags.

They’ll test your poop for evidence of C. diff infection. If they find it, they’ll start your treatment for it right away. They might not have any reason to look inside your colon for evidence of pseudomembranes unless you have complications or you aren’t responding to the treatment.

Sometimes, signs of pseudomembranous colitis show up on an imaging test (radiology). Your provider might see a pattern in the images that suggests severe colitis or damage to the mucosa, such as the “thumbprint sign” or the “accordion sign.” This might prompt further investigation.

To investigate further, the next step would be to look inside your colon for the cause of your symptoms. The exam to look inside your colon is called a colonoscopy. If your provider finds pseudomembranes during a colonoscopy, they’ll take a tissue sample (biopsy) and send it to a lab to confirm it.


Management and Treatment

What is the treatment for pseudomembranous colitis?

The treatment depends on the cause. You may need specific antibiotics for a bacterial infection, like C. diff, or you may need to discontinue medications that are causing or contributing to your colitis. In some cases, healthcare providers may prescribe medications to reduce inflammation in your colon.

Some people only need supportive care, like IV fluids for dehydration or IV nutrition so their colon can rest. Others may need treatment for complications or even intensive care. Some people with very severe colitis or with complications may need surgery to remove part of their colon (colectomy).

What is the drug of choice for pseudomembranous colitis caused by C. diff?

If C. diff infection is the cause of your pseudomembranous colitis, there are a few drugs that can treat it. Your provider will choose the best one for you. Drugs to treat C. diff infection include:


How can I prevent pseudomembranous colitis?

The most important way to prevent pseudomembranous colitis is to prevent the spread of C. diff in vulnerable communities, like hospitals and nursing homes. People in these communities are more likely to become infected and to develop more severe symptoms like pseudomembranous colitis.

Healthcare providers in these settings take special precautions to control C. diff infection:

  • Isolation. Healthcare providers isolate people infected with C. diff in their own room, or one shared only with other infected people. They use disposable gloves when they enter the room.
  • Handwashing. Frequent handwashing with soap and warm water is the best defense against C. diff, which is resistant to hand sanitizer. It’s especially important before handling food.
  • Disinfection. Many common disinfectants don’t work against C. diff, but chlorine-based products can. It’s important to disinfect all surfaces in contact with the infected person.

Outlook / Prognosis

Can pseudomembranous colitis be cured?

Yes, treatment can relieve pseudomembranous colitis. Most of the time, symptoms resolve quickly, but some people need more treatment than others. A persistent case of C. diff infection that keeps coming back may need a minor procedure to cure. Some complicated cases may require surgery.

What is the mortality rate for pseudomembranous colitis?

Only 2% of pseudomembranous colitis cases are fatal. The rate is closer to 15% among people in long-term care facilities, who are already immunocompromised. Toxic megacolon has a 35% fatality rate.

Living With

When should I contact a healthcare provider about possible pseudomembranous colitis?

Seek immediate care if you have:

  • Severe stomach pain or swelling.
  • Diarrhea more than five times a day.
  • Blood in your poop.
  • Not pooped for three days.
  • Not peed for a day or your pee is dark.
  • Fever above 102 degrees Fahrenheit (39 degrees Celsius) for three days.

A note from Cleveland Clinic

Bacterial infections that cause colitis are common, and most of the time, they aren’t serious. Not everyone who gets a C. diff infection will develop pseudomembranous colitis. But it can be scary if you do. You may be alarmed to learn that your colon is being injured on the inside. You may have upsetting symptoms, like pain and bleeding.

If you develop these symptoms, you need special care. But with care, your colon can heal. Mucous membranes like your colon lining heal well, once the injury has stopped. If your colitis symptoms don’t seem to be going away, talk to a healthcare provider. They’ll work to find and stop what’s causing your colitis and give your colon the rest it needs.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 08/29/2023.

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