What is Pseudomembranous Colitis?
Pseudomembranous colitis is a severe inflammation or irritation of the inner layer of the large intestine, often occurring as a result of taking antibiotics. It’s primarily caused by an intense infection from a bacterium named Clostridium difficile.
This has become more common in hospital settings over the last twenty years, which is a concern, as it can cause additional issues in already unwell patients.
What Causes Pseudomembranous Colitis?
Pseudomembranous colitis is usually caused by an infection from a bacterium called C. difficile. But there are other less common causes such as a lack of blood supply to the colon (ischemic colitis), a type of bowel disease that results in inflammation and ulcers (inflammatory bowel disease), an infection related to the herpes virus (cytomegalovirus-induced colitis), blood vessel inflammation (vasculitis), certain bacterial and parasitic infections, a rare disorder that results in inflammation of blood vessels throughout your body (Behcet’s Disease), certain chemotherapy drugs, and exposure to toxins like heavy metals.
Although C. difficile is often thought of as a germ that you can pick up in hospitals or care homes, it’s also a common cause of diarrhoea especially among older people who have been on antibiotics, or who have stayed in healthcare facilities.
There are several risk factors for a C. difficile infection. These include having had the infection before, old age, the use of medications which reduce stomach acid, having had gut surgery, having a feeding tube, a weak immune system, undergoing chemotherapy, suffering from chronic kidney disease, or a pre-existing bowel disease. But you can still get a C. difficile infection even if you don’t have any of these risk factors.
Risk Factors and Frequency for Pseudomembranous Colitis
C. difficile infections have been rising over the past two decades, making it one of the most common infections caught in medical settings. Every year in the United States, there are nearly half a million cases and 29,000 deaths linked to this. It has also been recognized in individuals without exposure to antibiotics or healthcare settings, leading to the term community-associated C difficile infection. This bacterium is the leading cause of infectious diarrhea in healthcare settings and can cause serious illness and you could potentially be fatal.
- Almost 500,000 cases and 29,000 deaths related to C. difficile are reported in the US annually.
- This infection isn’t only found in healthcare settings; it is also found in the community outside healthcare settings.
- C. difficile is the most common cause of infectious diarrhea in healthcare environments.
- Its infection can cause serious health issues and even potentially cause death.
- 13% of hospital patients will carry the C. difficile bacterium after a 2-week stay, increasing to 50% for patients staying over 4 weeks.
- The bacteria can also live in the colon of healthy people, affecting 2% to 5% of the general population who won’t show any signs of infection.
Signs and Symptoms of Pseudomembranous Colitis
Pseudomembranous colitis is a condition most often associated with diarrhea. This disease is caused by an infection with C. difficile, a type of bacteria, and can range from mild to severe. Some people may carry the bacteria without showing any symptoms, while others may have severe conditions such as toxic megacolon. The presence of pseudomembranes, a type of film that forms on the liner of the colon, usually suggests a more serious case. Other common symptoms to watch out for include fever, stomach cramps, and a higher than normal white blood cell count. Severe cases can also lead to a very high white blood cell count, low blood volume, low blood pressure, arthritis, and toxic megacolon. In 3% to 8% of severe cases, the infection can have life-threatening complications like blocked intestines (severe ileus), toxic megacolon, low blood volume, low blood pressure, kidney malfunction, a hole in the colon causing inflammation in the abdomen (peritonitis), and a severe infection that can cause organ failure (septic shock).
- Diarrhea
- Fever
- Abdominal cramps
- Increased white blood cell count
- Very high white blood cell count (in severe cases)
- Low blood volume (in severe cases)
- Low blood pressure (in severe cases)
- Arthritis (in severe cases)
- Toxic megacolon (in severe cases)
- Severe ileus, hypovolemia, kidney dysfunction, colon perforation and septic shock (in extreme cases)
Testing for Pseudomembranous Colitis
Doctors might suspect that a patient has an infection caused by a bacterium called C. difficile if the patient has diarrhea that tests positive for blood along with other signs like a swollen colon (known as toxic megacolon). They’ll be especially suspicious if the patient has been in a hospital, taken antibiotics or chemotherapy drugs, or shows an extremely high white blood cell count (referred to as a leukemoid reaction). These are all factors that can raise the likelihood of a C. difficile infection.
To confirm the suspicion, doctors use lab tests to look for specific toxins produced by C. difficile that cause a condition called pseudomembranous colitis. This condition results in inflammation in the colon that leads to diarrhea and other symptoms.
Typically, the testing process involves two steps. First, a laboratory technique known as an enzyme immunoassay (EIA) is used to check for an antigen (a substance that triggers an immune response) called glutamate dehydrogenase. This antigen is present in most C. difficile bacteria. Then, a second EIA test screens for two toxins, known as toxin A and toxin B, produced by C. difficile.
If the results of these tests don’t match up, another type of test called a nucleic acid amplification test may be used. This test, which includes methods like polymerase chain reaction and loop-mediated isothermal amplification, is highly accurate and can help settle any discrepancies in the earlier test results. But the results of these tests must be interpreted carefully since they can’t tell the difference between a patient who merely carries C. difficile without being sick and a patient who is actively infected and showing symptoms.
If a patient in a hospital has been having three or more episodes of liquid diarrhea every day, doctors will likely order tests for C. difficile. But they don’t usually perform these tests to confirm that treatment has been successful because even once a patient’s symptoms have resolved, about 60% of the time the test will still be positive. And unless a doctor continues to suspect C. difficile infection in spite of negative test results, the patient isn’t likely to be sent for an endoscopy (a procedure that uses a thin, flexible tube with a light and camera attached to it to examine the digestive tract). This is because endoscopy can have some risks and tends to be expensive.
Treatment Options for Pseudomembranous Colitis
In the United States, the Food and Drug Administration has approved only two drugs – vancomycin and fidaxomicin – for treating C. difficile colitis, a bacterial infection that affects the colon. However, for the last forty years, metronidazole has also been commonly used as an initial treatment. Research shows that metronidazole’s effectiveness is almost equal to that of vancomycin in treating mild to moderate C. difficile colitis.
Severe C. difficile colitis is characterised by a high white blood cell count, low blood pressure, the need for intensive care unit treatment, increased levels of lactate in the blood, and signs of damage to organs like the kidneys or the brain. Usually, a condition called pseudomembranous colitis involving inflammation and the development of a membrane-like layer in the colon, also indicates severe C. difficile disease.
Oral vancomycin is the treatment of choice for severe C. difficile colitis because it has higher cure rates compared to other methods. If the infection comes back after treatment with oral vancomycin, then other drugs like fidaxomicin or rifaximin can be considered.
If the C. difficile colitis becomes extremely severe and does not respond to medication, or if complications like an abnormally large colon or a hole in the colon occur, surgery might need to be carried out. Surgery could involve the removal of part of the colon.
C. difficile colitis often comes back after initial treatment, and usually, the same antibiotics are used again. However, if the severity of the disease increases, other treatments may be needed. If the infection keeps coming back even after three rounds of treatment with oral vancomycin, fecal microbiota transplant (introducing healthy bacteria into the colon) has been shown to be beneficial in a few small studies.
What else can Pseudomembranous Colitis be?
When looking at Pseudomembranous colitis caused by C. difficile, it’s important to differentiate it from other causes of dysentery (severe diarrhea with mucus and blood). These could include:
- Diverticulitis
- Crohn’s disease
- Irritable bowel disease
- Salmonella infection
- Vibrio infections
- Various types of bacterial and viral gastroenteritis (stomach flu)
Differentiating between these diagnoses is vital to ensure the right treatment.
Possible Complications When Diagnosed with Pseudomembranous Colitis
There are several serious conditions that may arise in your digestive system. These include:
- Colitis, which is inflammation of the colon
- Bowel perforation, where there’s a hole in the wall of your gut
- Toxic megacolon, a life-threatening condition that causes your large intestine to rapidly expand
- Sepsis, a dangerous reaction to infection that can lead to organ failure if not treated promptly
