Unanswered questions
How can the incidence of bacterial intestinal infection be reduced?
Given the increased incidence of inflammatory bowel disease in the developed world, what environmental factors are responsible?
Does bacterial gastroenteritis cause irritable bowel syndrome in children, as is reported in adults?
Are antibiotics advisable for patients with haemorrhagic colitis caused by Escherichia coli that produce shiga toxin?
What are the aetiology and pathogenesis of infant colitis?
How should I screen for inflammatory bowel disease?
Screening blood tests can be helpful, but in the context of bloody diarrhoea their role is limited. In a study of children presenting to a specialist paediatric gastroenterology clinic with suspected inflammatory bowel disease the simple combination of haemoglobin and platelet count was useful.7 Using "one or both tests abnormal" as a positive outcome gave a sensitivity of 92%, a specificity of 80%, and positive and negative predictive values of 77% and 93% for ulcerative colitis. However, another study found that haemoglobin, albumin, erythrocyte sedimentation rate, and C reactive protein were normal in 19% of children presenting with clinically mild ulcerative colitis.8 Normal blood tests do not rule out inflammatory bowel disease in children with bloody diarrhoea. Moreover, abnormal results may be found in children with bacterial gastroenteritis. In the absence of an identified stool pathogen, endoscopic evaluation is required in children with severe or persistent symptoms (fig 1).
How can I recognise and manage severe colitis?
Severe bloody diarrhoea (more than five bloody stools daily) requires urgent referral to a paediatric gastroenterologist. Severe colitis is associated with an increased risk of non-response to medical treatment, progression to toxic megacolon, and colonic perforation. Early referral may reduce these risks. Intravenous corticosteroids or ciclosporin are often effective in severe disease, and children need expert monitoring for signs of deterioration. In some cases emergency colectomy may be life saving.
Which diagnoses are most likely in infants?
Infant colitis
Colonoscopy often shows mucosal inflammation and ulceration in infants who present with bloody diarrhoea. Although cows’ milk allergy is usually suspected, the aetiology is often uncertain. Allergy is probably overdiagnosed.9 10 Many infants with bloody diarrhoea are breast fed and have "breast milk colitis." In these cases, it has been proposed that small but immunologically relevant amounts of intact maternal dietary antigens might be transferred to breast milk via the mother’s bloodstream. However, this hypothesis has not been confirmed. A recent study of 40 infants presenting with blood in the stool provided a useful insight.10 The mean age at presentation was 3 months (range 1-6). The stools were watery in 38% and mucoid in 73%. Colonoscopy showed mucosal aphthae (33%), microscopic inflammation (33%), and focal eosinophilic infiltration (23%). The infants were randomly allocated to a cows’ milk-free diet (n=19) or a normal diet (n=21), with breastfeeding mothers in the first group adopting a cows’ milk elimination diet. They were reviewed at one and 12 months. During follow-up, bleeding was often intermittent, with an average time to the final episode of 24 days (range 1-85). All of the infants thrived. Cows’ milk elimination did not affect the duration of bleeding, and re-challenge supported a diagnosis of cows’ milk allergy in only 18%. The authors concluded that infant colitis is usually a benign self limiting disorder.
Necrotising enterocolitis
Necrotising enterocolitis is a serious disorder, rarely seen in primary care. It is characterised by diffuse or focal ulceration and necrosis in the small intestine and colon, and it may present with rectal bleeding or bloody diarrhoea. Other common features include abdominal distension, bilious vomiting, and signs of septicaemia. It mainly occurs in premature infants in the neonatal unit, although it can develop at any time up to 10 weeks of age. Moreover, up to 10% of cases are in full term infants.11 In such cases, predisposing factors such as cardiac disease may be present.11 12 When necrotising enterocolitis does occur in full term infants, the onset is usually within the first week of life.11 13 If it is suspected then urgent hospital referral is necessary. Abdominal radiography may show features to support the diagnosis.
Hirschsprung’s disease
Hirschsprung’s disease (congenital absence of ganglion cells in the colon) occurs in 1:5000 live births. About 80% of affected children present in the first year of life. In more than 90% of affected infants the passage of meconium is delayed beyond the first 24 hours. The classic presentation is with constipation. However, 25% of infants present with enterocolitis causing abdominal distension, and severe watery and sometimes bloody diarrhoea.14 This may cause hypovolaemic shock and colonic perforation, and mortality is 33% in these patients.15 Early diagnosis is therefore essential.
Tips for non-specialists
Children with fewer than six stools daily may be managed in primary care if they are not systemically unwell and do not have an acute abdomen
Evidence of systemic illness includes fever, tachycardia, pallor, and shock
Evidence of an abdominal surgical emergency includes severe pain, persistent or bilious vomiting, haematemesis, distension, tenderness, a palpable mass, and signs of septicaemia or shock
Consider inflammatory bowel disease in children with evidence of chronic disease—persistent or recurrent bloody diarrhoea or other gastrointestinal symptoms, weight loss, or poor growth
Severe colitis—associated with severe bloody diarrhoea—is life threatening and requires immediate referral to a paediatric gastroenterologist
What other disorders should I consider?