• Pseudomembranous colitis is due infection by Clostridium difficle
• A gram-positive anaerobic bacillus
• Not identified until 1953 because it was 'difficult' to culture
• Spores are commonly found in the hospital environment

Pathophysiology

• Normal stool contains >500 different bacteria at a concentration of 10¹² per gram
• Antibiotic therapy can change the faecal flora
• Broad-spectrum antibiotics are main culprits
• Particular problem with lincomycin and clindomycin - but rarely used
• Allows colonisation by C. difficle transmitted by the faecal-oral route
• Exotoxins (Toxin A & B) produced by bacteria are cytotoxic
• Act via cell membrane receptors
• Produces mucosal inflammation and cell damage
• If severe epithelial necrosis a pseudo-membrane is formed
• Consists of mucin, fibrin, leucocytes and cellular debris

Clinical features

• 50% of neonates are transient healthy carriers of C. difficle
• Only 1% of adults are also asymptomatic carriers
• 10% patients on antibiotics develop diarrhoea
• Only 1% develop pseudomembranous colitis
• The spectrum of symptomatic disease includes:
  • Mild diarrhoea
  • Colitis without pseudo-membrane formation
  • Pseudomembranous colitis
  • Fulminant colitis
• Diagnosis is confirmed by the detection of toxin in the stool by ELISA

Treatment

• Asymptomatic carriers require no active treatment
• Those with mild diarrhoea should have their antibiotics stopped
• If colitis present need active treatment with oral antibiotics:
  • Metronidazole - first line therapy
  • Vancomycin - second line therapy
• Symptoms usually improve within 72 hours
• May take 10 days for diarrhoea to stop
• Pseudomembranous colitis requires aggressive resuscitation and treatment
• If fulminant colitis with toxic megacolon or perforation surgery may be necessary

• 10% patients relapse after initial treatment

• Due to either failure of eradication or re-infection

Bibliography

Bartlett J G.  Clinical practice:  antibiotic-associated diarrhoea.  N Eng J Med 2002;  346:  334-339.

Cleary R K.  Clostridium difficle-associated diarrhea and colitis.  Dis Colon Rectum 1998;  41:  1435-1449.

Hurley B W,  Nguyen C C.  The spectrum of pseudomembranous enterocolitis and antibiotic-associated diarrhoea.  Arch Int Med 2002;  162:  2117-2184

Kelly C P,  Pothoulakis C,  Lamont J T.  Clostridium difficle colitis.  N Eng J Med 1994;  330:  257-262.

Kyne L,  Farrell R J,  Kelly C P.  Clostridium difficle.  Gastroenterol Clin North Am 2001;  30:  753-777.

Last updated: 05 January 2008

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