pseudomembranous colitis

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Pseudomembranous colitis is a very severe form of antibiotic associated colitis or diarrhoea. It is usually the result of the toxin of Clostridium difficile.

Most cases are hospital-acquired. Infection is faeco-oral, for example, via the patient's or staff's hands from a contaminated commode or equipment - rectal thermometer, sigmoidoscope, etc. Sixty percent of cases occur in the elderly.


  • Clostridium difficile toxins (A and B)


  • Human gastrointestinal tract
  • Spores may be present on environmental surfaces contaminated by symptomatic persons


  • person-to-person spread from symptomatic patients either directly or indirectly via contaminated hands of healthcare/other care workers
  • via contact with environmentally contaminated surfaces e.g. commodes
  • spread does not occur from asymptomatic carriers
  • (1)

Incubation period:

  • difficult to establish incubation period
  • among patients commencing antibiotics, diarrhoea usually starts within 1-2 days of commencing antibiotics but can occur several weeks after antibiotic treatment


  • Most infectious when symptomatic
  • Infectiousness reduces with treatment and decreasing severity of symptoms
  • Stopping the implicated antibiotics (if possible) may be indicated

Referral criteria:

  • refer people in the community with suspected or confirmed C. difficile infection to hospital if they are severely unwell, or their symptoms or signs worsen rapidly or significantly at any time. Refer urgently if the person has a life-threatening infection

  • consider referring people in the community to hospital if they could be at high risk of complications or recurrence because of individual factors such as age, frailty or comorbidities

  • ensure that people in hospital with suspected or confirmed C. difficile infection have care from a multidisciplinary team that may include a microbiologist, infectious diseases specialist, gastroenterologist, surgeon, pharmacist or dietitian, as needed.


  • C. difficile spores are hardy and may remain on environmental surfaces for many weeks. Thorough environmental cleaning with suitable agents e.g. chlorine containing products is required to reduce transmission
  • a review (3) noted that:
    • oral metronidazole appears acceptable for the treatment of a first episode of C. difficile
    • patients with persistent diarrhoea after 48 hours of appropriate anti-Clostridiodes therapy should be addressed to specialist


Last edited 05/2022