Table of Contents
Overview – Pseudomembranous Colitis
Pseudomembranous colitis is a potentially life-threatening inflammatory bowel condition most commonly triggered by recent antibiotic use. It occurs due to Clostridium difficile overgrowth, leading to toxin-mediated colonic inflammation and characteristic pseudomembrane formation. Prompt diagnosis and targeted antimicrobial therapy are essential to prevent serious complications like toxic megacolon or perforation.
Definition
Acute colonic inflammation caused by Clostridium difficile overgrowth following antibiotic-associated disruption of gut flora, resulting in fibrous pseudomembranes and diarrhoea.
Aetiology
- Antibiotic use (especially clindamycin, cephalosporins, fluoroquinolones, amoxicillin)
- Clostridium difficile overgrowth, often nosocomial
Pathogenesis
- Antibiotics eliminate commensal flora
- C. difficile proliferates unchecked
- Produces enterotoxins → mucosal inflammation
- Fibrin, necrotic epithelium, neutrophils, and mucin form pseudomembranes
Morphology
- Mucosal ulceration, friability, and bleeding
- Pseudomembranes: Yellow-white plaques of fibrin and neutrophilic exudate
- May resemble inflammatory bowel disease on colonoscopy
Clinical Features
- Onset: Usually within 2 days of antibiotics, may persist up to 2 weeks after cessation
- Symptoms:
- Fever
- Lower abdominal cramps
- Profuse watery diarrhoea (up to 10×/day)
- Haematochezia
Investigations
- Colonoscopy: Visualisation of pseudomembranes
- Stool toxin assay: Detection of C. difficile toxins A and B
- Exclude other diagnoses: Crohn’s, UC, CRC
Treatment
- Discontinue the inciting antibiotic
- Anti-Clostridial antibiotics:
- Metronidazole (first-line in mild cases)
- Oral Vancomycin (for moderate/severe cases)
- Supportive care:
- Fluid and electrolyte replacement
- Consider probiotics
Complications
- Dehydration & electrolyte imbalance
- Toxic megacolon
- Bowel perforation
- Sepsis
Summary – Pseudomembranous Colitis
Pseudomembranous colitis is a toxin-mediated colitis caused by C. difficile, commonly triggered by recent antibiotic use. Classic signs include profuse diarrhoea, fever, and abdominal pain. Diagnosis is confirmed by toxin assay and colonoscopy. Timely discontinuation of the offending antibiotic and targeted therapy with metronidazole or vancomycin significantly improves outcomes. Learn more conditions in the Gastrointestinal System.