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Pseudomembranous colitis - Causes
Last reviewed: 06.07.2025
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How does pseudomembranous colitis develop?
There are four main causes of C. difficile-associated pseudomembranous colitis.
Imbalance of bacteria in the colon
Suppression of intestinal flora leads to excessive proliferation of C. difficile, which are capable of secreting exotoxin. This is usually associated with the use of antibiotics, sometimes it can be caused by the use of antimicrobial chemotherapeutic drugs, especially if they are capable of suppressing normal intestinal flora. All groups of antibiotics, with the exception of aminoglycosides, can cause the disease. Diarrhea can occur during the use of antibiotics or within 4-6 months after its completion. This disease usually occurs after the use of clindamycin, ampicillin or cephalosporins. Much less often it can occur with the use of metronidazole, vancomycin, fluoroquinolones, co-trimoxazole and aminoglycosides.
The presence of C. difficile in the colon as endogenous flora (in approximately 3% of healthy individuals) or exogenous flora
In 10-30% of patients, this microorganism can be isolated from the feces within a few days after hospitalization. Despite the fact that Clostridium difficille is often isolated from the feces of various healthy animals, they are not considered a source of infection.
Endotoxin production by C difficile
About 25% of C difficile strains isolated from patients do not produce either toxin A or toxin B; they are considered nontoxigenic and never cause diarrhea or colitis. Toxin A is the cause of clinical manifestations of the disease, and toxin B has cytopathic activity that is detected by standard culture methods. Patients colonized with nontoxin-producing strains of Clostridium difficile do not have clinical manifestations, and conversely, clinical signs of the disease occur only in patients colonized with toxin-producing strains. Toxin can be detected in the stool of 15-25% of patients with diarrhea and more than 95% of patients with pseudomembranous colitis.
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Age of patients
For unknown reasons, people over 50 years of age are most susceptible to the infection. In newborns, Clostridium difficile colonization is observed in 60-70% of cases, but symptoms of the disease do not occur. Patients at high risk of the disease include those who have undergone surgery (especially abdominal surgery), are treated in intensive care units, have severe chronic diseases, and have a nasogastric tube. The role of proton pump inhibitors and histamine receptor antagonists used to prevent the development of gastric ulcers in intensive care patients in the pathogenesis of diarrhea associated with C. difficile has not been definitively established.
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