This condition causes serious or life-threatening diarrhea. It often follows antibiotic use and often affects people in the hospital for other conditions.
Update Date: 03.09.2025
Pseudomembranous (SOO-doe-mem-bruh-nus) colitis is advanced inflammation of the colon that can cause serious or life-threatening diarrhea. Pseudomembranous colitis is most often caused by bacteria that produce tissue-damaging toxins.
Colitis is inflammation of the colon. Inflammation is the immune system reaction to disease or injury. An inflammatory reaction increases blood flow, releases proteins that regulate cells' defenses and delivers disease-fighting cells. Inflammation is a part of the process for healing tissues, but over time inflammation also may damage tissues.
Advanced inflammation in the colon can sometimes result in the formation of pseudomembranes. These are patches of irregular tissues lining the colon. These tissues are made up of mucus, debris from dead cells, blood-clotting material and immune system cells.
The most common cause of pseudomembranous colitis is serious infection with a bacterium called Clostridioides difficile, also called C. diff. The illness often affects people who are in the hospital for other conditions. C. diff-related diarrhea often happens during or after use of antibiotics.
Treatment includes an antibiotic that targets C. diff and steps to restore body fluids. Other treatments may help restore healthy bacteria that help protect the colon.
Symptoms of pseudomembranous colitis may include:
The beginning of symptoms is often related to recent antibiotic treatment. Symptoms may start during or after treatment. Most often, symptoms appear within two weeks of antibiotic treatment and rarely, after 10 weeks.
If you are currently taking or have recently taken antibiotics and you develop diarrhea, contact your healthcare professional. Also, see your healthcare professional anytime you have severe diarrhea with a fever, painful stomach cramps, or blood or pus in your stool.
The most common cause of pseudomembranous colitis is the bacterium Clostridioides difficile, also called C. diff. In some cases, a C. diff infection is mild to moderate. Pseudomembranous colitis is a sign of more serious disease.
C. diff bacteria enter the body through the mouth. When they reach the part of the large intestine, called the colon, the bacteria can release toxic spores that damage tissues. These toxins destroy cells, disrupt colon function and cause watery diarrhea.
Outside the colon, the bacteria aren't active. They can live for a long time in places such as:
When bacteria once again find their way into a person's digestive system, they become active again and cause infection. Because C. diff can survive outside the body, the bacteria spread easily.
Typically, the colon has many types of bacteria that play a role in digestion. They generally keep each other in check, and the colon has other means to protect from possibly harmful bacteria.
Antibiotics can kill the good bacteria and change other factors that protect the colon. If a person already has C. diff or is newly exposed to C. diff, the germs have a chance to thrive and cause disease.
Any antibiotic may create conditions that allow C. diff to grow. But antibiotics that fight many different types of bacteria, called broad spectrum antibiotics, are often linked to C. diff-related diarrhea. These include:
Other factors can create conditions in the colon that make C. diff infection more likely. These include:
Less common causes of pseudomembranous colitis include:
Factors that may increase the risk of pseudomembranous colitis include:
Treatment of pseudomembranous colitis is usually successful. However, even with prompt diagnosis and treatment, pseudomembranous colitis can be life-threatening. Possible complications include:
In addition, pseudomembranous colitis may sometimes return, days or even weeks after apparently successful treatment.
To help prevent the spread of C. difficile, hospitals and other healthcare facilities follow strict infection-control guidelines. If you have a friend or family member in a hospital or nursing home, follow hygiene guidelines and ask questions if you see someone not following guidelines.
Preventive measures include:
Tests and procedures that may be used to diagnose the cause of diarrhea:
Treatments for pseudomembranous colitis usually include:
When antibiotic treatments don't work, your healthcare team may look for other possible causes for pseudomembranous colitis or try other treatments.
Sometimes treatments may be used to restore healthy bacteria in the colon. Stool from a healthy donor — often from stool banks — are screened to make sure they don't carry harmful germs. This stool with healthy bacteria is transplanted into the diseased colon to restore typical gut bacteria. This is called fecal microbiota transplantation.
The stool with healthy bacteria is delivered to the colon with a scope that passes through the anus. Or the transplant is delivered through a tube that passes through the nose and down to the stomach.
Two other methods to restore healthy bacteria include:
Serious damage to the colon, rupture or toxic megacolon may require surgery. Procedures may include:
Pseudomembranous colitis is often diagnosed when you are already under care in a hospital or nursing home. Diagnosis and treatment are then a continuation of current care. You also may see your primary healthcare professional first.
If you are seeing your primary healthcare professional for diarrhea, you can write down the following information before your appointment:
Some basic questions you might want to ask include:
Don't hesitate to ask additional questions. And, if possible, take a family member or friend along to help you remember the information you're given.
Your healthcare professional is likely to ask you several questions, such as:
While you're waiting for your appointment, drink plenty of fluids to help prevent dehydration. Sports drinks, oral rehydration solutions (Pedialyte, Ceralyte, others), noncaffeinated soft drinks, broths and fruit juices are good options.
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