Clostridioides difficile (C. diff) is a bacterium that causes infection and inflammation (colitis) in the colon. This occurs when the bacteria release toxins that damage the intestinal lining. The infection primarily results from the disruption of the gut’s natural microbial balance, often after a person has taken antibiotics for another illness. The most common symptom is severe, watery diarrhea, sometimes accompanied by abdominal cramping.
Understanding the Risk of Untreated C. diff
While a very mild C. diff infection may rarely resolve on its own, relying on this outcome is dangerous. The infection is generally progressive and worsens without specific medical intervention. The toxins produced by the bacteria cause increasing damage to the colon wall, leading to severe, life-threatening complications.
Untreated C. diff increases the risk of severe dehydration and electrolyte loss due to frequent diarrhea. This fluid loss can lead to acute kidney failure. A severe complication is toxic megacolon, where inflammation causes the colon to become massively enlarged, preventing the passage of gas or stool.
Toxic megacolon carries a high risk of colonic perforation (a tear in the intestinal wall). If the colon perforates, bacteria spill into the abdominal cavity, causing a widespread, life-threatening infection called peritonitis. Furthermore, any severe, untreated C. diff infection can trigger sepsis, which can rapidly lead to tissue damage, organ failure, and death.
Diagnosing C. diff and Determining Severity
C. diff diagnosis requires unexplained diarrhea (three or more unformed stools in 24 hours) and a positive stool test for the bacteria or its toxins. Laboratory methods include testing the stool sample for toxins or using a Nucleic Acid Amplification Test (PCR) to detect toxin-producing genes. Testing is typically reserved for symptomatic patients, as the bacteria can colonize the gut without causing disease.
Diagnostic results and clinical signs classify the infection’s severity, guiding the treatment path. Severity is categorized as non-severe, severe, or fulminant, based on specific laboratory markers. Doctors assess the white blood cell count and serum creatinine level (indicating kidney function) to determine the classification.
A severe infection is suggested by a white blood cell count above 15,000 cells/µL or a creatinine level elevated more than 50% above baseline. Fulminant C. diff is indicated by life-threatening signs such as low blood pressure, shock, ileus, or toxic megacolon. Accurate classification is necessary for selecting the most effective treatment strategy.
Medical Treatment Approaches
Management begins by stopping any non-C. diff antibiotics the patient is taking, as these disrupt the gut flora and fuel the infection. Mild to moderate cases are treated with targeted antibiotics that kill C. diff specifically within the gut. Oral vancomycin or fidaxomicin are the preferred first-line treatments for an initial episode due to their high cure rates.
Metronidazole is an alternative, particularly for non-severe cases, but is often considered second-line as it is less effective than vancomycin or fidaxomicin. These C. diff-specific antibiotics are taken orally to ensure high concentrations reach the colon. For severe or complicated infections, oral vancomycin is often combined with intravenous metronidazole to treat localized and systemic infection.
Supportive care focuses on replacing fluids and electrolytes lost through severe diarrhea. For recurrent infection, Fecal Microbiota Transplantation (FMT) is a highly effective advanced therapy. FMT involves introducing screened stool from a healthy donor into the patient’s colon, restoring the protective gut bacteria to outcompete the C. diff.
Preventing Future Episodes
Recurrence is a major challenge, as approximately one in six people experience a repeat infection within eight weeks of initial recovery. The risk of recurrence increases significantly with each subsequent episode, emphasizing the need for proactive prevention. A central pillar of prevention is antibiotic stewardship, which limits the use of broad-spectrum antibiotics to allow the gut microbiota to recover.
Infection control measures are crucial, especially in healthcare settings, to prevent the spread of C. diff spores. C. diff forms spores that are resistant to alcohol-based hand gels and can survive on surfaces for extended periods. Strict hand hygiene using soap and water is recommended for anyone in contact with an infected person, as the physical scrubbing action removes the spores.
Specific prophylactic measures are used for patients at high risk of recurrence, such as those with multiple previous episodes. These measures include a prolonged or tapered course of vancomycin to suppress the bacteria while the normal gut flora reestablishes itself. Additionally, the monoclonal antibody bezlotoxumab can be administered alongside antibiotic treatment to neutralize the C. diff toxin B, providing protection against future recurrence.