defined as total or segmental non-obstructive colonic distension associated with systemic toxicity.

Epidemiology

• Toxic megacolon has a reported lifetime incidence of less than 5% in patients with inflammatory bowel disease (IBD) and 0.4% to 3% in patients with pseudomembranous or Clostridium difficilecolitis.

Causes

• IBD (most common cause)
• C. Difficile infection
• Salmonella colitis
• It has also been reported as a consequence of ischaemic colitis, obstructive colon cancer, diverticulitis, volvulus and other inflammatory diseases

Pathophysiology

• Decreased mucosal blood supply from the colonic distension leads to disruption of mucosal defences, and subsequent increased translocation of bacteria and toxins into systemic circulation.

Diagnosis

Diarrhoea >6 stools per day + signs of systemic upset:

• fever
• tachycardia
• anaemia
• raised esr