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Childhood diarrhoea is most often caused by infection. Much less often, however, it is due to other causes - eg, malabsorption, endocrine abnormalities, hormone-secreting tumours, pancreatic and liver dysfunction. Acute-onset diarrhoea is usually self-limiting but may have a protracted course. The most common complication of acute diarrhoea is dehydration. Non-infectious causes of diarrhoea may have other systemic signs and symptoms and should be considered in all cases, especially if an acute-onset diarrhoea fails to resolve within 14 days or if the condition recurs.
See also separate article Gastroenteritis in Children.
Infectious diarrhoea in children is mostly viral; worrying features that should suggest a diagnosis other than acute, viral gastroenteritis include:
- A generally unwell child - out of proportion to the level of dehydration.
- Abdominal pain with tenderness and guarding (possible surgical problem - eg, appendicitis or intussusception).
- Shock, pallor, jaundice, poor urinary output.
- Bilious vomiting.
- Blood in stool (possible intussusception or haemolytic uraemic syndrome (HUS)).
Causes of acute diarrhoea
- Viral infection: mainly rotavirus but others include norovirus, echoviruses and enteroviruses.
- Bacterial infection: suggested by high pyrexia and bloody diarrhoea. Common bacterial pathogens include Shigella spp., Salmonella spp. and Campylobacter spp.
- Protozoal infection: chronic infections might suggest protozoans, for example Giardia lamblia.
- Systemic infection: eg, urinary tract infection, pneumonia, otitis media, meningitis, septicaemia.
- Antibiotic-associated and rarely pseudomembranous colitis.
- Dietary: food allergy or intolerance (lactose intolerance, cows' milk protein intolerance); starvation stools.
- Surgical conditions: eg, appendicitis; intussusception; partial bowel obstruction - eg, volvulus, Hirschsprung's disease; Meckel's diverticulum; short bowel syndrome.
- Malabsorption: cystic fibrosis, coeliac disease.
- Inflammation: ulcerative colitis, Crohn's disease.
- Miscellaneous: constipation with overflow, HUS, toddler's diarrhoea, hyperthyroidism.
Causes of bloody diarrhoea in infants and children
Bloody diarrhoea should arouse suspicion of bacterial infection. Bloody diarrhoea in children, when due to acute enteric infection, is usually caused by either Campylobacter spp. (mainly C. jejuni), where bloody diarrhoea may be present in up to 29% of cases, and verocytotoxin-producing Escherichia coli (VTEC O157) infections where bloody diarrhoea may be present in up to 90% of cases.
- Infants aged up to 1 year:
- Common: intestinal infection, infant colitis (nonspecific colitis, breast-milk colitis, cows' milk colitis).
- Less common or rare: intestinal ischaemia (intussusception, malrotation and volvulus), necrotising enterocolitis, Hirschsprung's disease, inflammatory bowel disease (Crohn's colitis, ulcerative colitis), systemic vasculitis, factitious illness.
- Children aged over 1 year:
- Common: intestinal infection, inflammatory bowel disease (Crohn's colitis, ulcerative colitis), juvenile polyp.
- Less common or rare: intestinal ischaemia (intussusception, malrotation and volvulus), mucosal prolapse, systemic vasculitis (eg, Henoch-Schönlein purpura), factitious illness.
- The patient may or may not be otherwise unwell with systemic symptoms.
- Food history can be helpful. Establish whether anyone else in the family is affected.
- Nonspecific non-focal abdominal pain and cramping are common.
- Water exposure: swimming pools have been associated with outbreaks of shigellosis, giardiasis, cryptosporidiosis and amoebiasis.
- Travel history may indicate a cause for diarrhoea. Enterotoxigenic E. coli is the leading cause of travellers' diarrhoea.
- Animal exposure: for example, exposure to young dogs or cats is associated with Campylobacter spp.
- Dehydration is the principal cause of morbidity and mortality. Loss of more than 10% body weight will lead to shock with falling blood pressure and tachycardia, coma and anuria. See also separate article Assessing Dehydration in Children.
- There may be evidence of failure to thrive and malnutrition.
- Abdominal pain: pain does not increase with palpation. Focal abdominal pain which is worse on palpation, rebound tenderness, or guarding need further assessment (usually urgent hospital admission for possible appendicitis).
- Stool culture: including examination for ova, cysts and parasites.
- Rotavirus antigen tests: false-negative rate is approximately 50%, and false-positive results occur, particularly in the presence of blood in the stools. Adenovirus (serotype 40 and 41) antigen can be detected by enzyme immunoassay.
- White cell count is usually normal but may be raised in some bacterial infections.
- Renal function and electrolytes. Occasionally, a protein-losing enteropathy may lead to a low serum albumin.
- Other investigations will depend on the individual situation. Further investigations may include endomysial antibodies (coeliac disease), intestinal biopsy (coeliac disease or inflammatory bowel disease), and sweat test (cystic fibrosis) if indicated, especially if diarrhoea persists.
- Most infectious diarrhoea is self-limiting and medical care is mainly supportive. The important aspects of management are recognition of more serious causes of diarrhoea, and adequate oral rehydration at an early stage. Infants under six months of age are at greatest risk of dehydration.
- The majority of children can be managed safely in the community, but there should be a lower threshold for admission to hospital for infants aged under six months. Small amounts of fluid given frequently are often tolerated, even when vomiting has been a prominent symptom.
- Breast-feeding: continued use of breast milk has been shown to be beneficial in children with acute diarrhoea.
- In treatment of diarrhoea, the most important factor is to maintain hydration.
- Racecadotril is an intestinal antisecretory enkephalinase inhibitor. It inhibits the break down of endogenous enkephalins and so reduces the hypersecretion of water and electrolytes into the intestine. It does not modify the duration of intestinal transit. It is licensed for the complementary symptomatic treatment of acute diarrhoea together with oral rehydration (and the usual support measures)when these measures alone are insufficient and is not possible to treat the cause.
- Antibiotic therapy is nearly always inappropriate in view of the usual viral aetiology but may be required for proven bacterial or protozoal causes of gastroenteritis. When required, antibiotic regimes will be determined by the results of stool culture and sensitivities and local guidelines.
- Loperamide has been shown to reduce the duration of diarrhoea, but adverse effects are unclear and it should not be prescribed.
- Consider hospital admission if:
- There is any concern regarding the underlying diagnosis.
- There are signs of dehydration, especially if aged under six months.
- There is inability to comply with oral rehydration - eg, vomiting, poor social circumstances.
- There is a pre-existing medical condition which may worsen with diarrhoea (eg, diabetes).
Primary care management of acute bloody diarrhoea in children
- Always seek urgent specialist advice whenever a child is reported to have had a single acute episode of bloody diarrhoea.
- Referral is an emergency where significant dehydration, acute abdominal pain, or other clinical features are noted, indicating the possible need for surgical intervention.
- There should be a high index of suspicion of VTEC O157 infection in a child who has recently (within 21 days) visited an open farm, where there has been contact with another known or suspected case of VTEC O157, or who is living in an area where a suspected or confirmed outbreak of VTEC O157 infection exists.
- Do not treat with antibiotics, non-steroidal anti inflammatory drugs, narcotic analgesics or antimotility drugs before referral.
- Infectious bloody diarrhoea must be reported promptly, preferably by telephone, to the local Health Protection Unit.
- Rotavirus infection may lead to dehydration and also to lactose intolerance.
- Bacterial bowel infection may, rarely, lead to infection at other sites, including septicaemia, meningitis and osteomyelitis. Infection may also lead to bowel perforation, intussusception, appendicitis or liver abscess. These complications are very uncommon but need to be considered if the child is particularly unwell or not making the expected recovery.
- Other rare complications include HUS and Reiter's syndrome.
- Giardia spp. infection may lead to chronic fat malabsorption.
- Carrier states are observed after some infections - eg, rotavirus and salmonella infections.
- E. coli O157 is the most common, but not only, cause of HUS. It may also cause haemorrhagic colitis.
- With proper management, prognosis is very good in developed countries.
- Mortality is caused predominantly by dehydration and secondary malnutrition.
- Neonates and young infants are at particular risk of dehydration and malnutrition.
- Food hygiene (storage, handling, cooking).
- Hand washing.
- Appropriate exclusion of children with diarrhoea, eg from nurseries.
- Vaccination: routine immunisation against rotavirus has been added to the UK immunisation schedule and will be available from September 2013. Rotarix® is administered orally at 2 and 3 months of age. Salmonella typhi vaccine is recommended for travellers to countries with a high incidence. Vibrio spp. vaccine is available but only protects 50% of immunised persons for 3-6 months and is not indicated for use.
Diarrhoea lasting for more than two weeks, particularly if associated with weight loss, needs further investigation.
- A well child with no weight loss:
- Toddler's diarrhoea typically occurs in the second year of life and is associated with undigested food such as peas and carrots in the stools. The child is well and growing normally. It is thought to relate to a rapid intestinal transit time. It resolves by the age of 4 years.
- Breast-fed babies often have liquid and abnormal stools. This is normal and doesn't need any further investigation if the baby is otherwise well and thriving.
- An unwell child with weight loss:
- Food intolerance - eg, cows' milk protein intolerance.
- Inability to digest nutrients - eg, pancreatic insufficiency, cystic fibrosis.
- Small intestinal disease: coeliac disease, food-sensitive enteropathy, inborn error of digestion or absorption, short bowel syndrome.
- Inflammatory bowel disease: Crohn's disease, ulcerative colitis.
- Intestinal parasites: eg, Giardia lamblia.
- Chronic enteric infection: stagnant loop syndrome.
- Iatrogenic: therapeutic diets, drugs (eg, excessive laxatives).
- Miscellaneous: eg, acrodermatitis enteropathica, immunodeficiency, Shwachman-Diamond syndrome, hyperthyroidism.
- Stool microscopy, culture and sensitivities; ova, cysts and parasites.
- Endomysial antibodies, jejunal biopsy (coeliac disease).
- Sweat test (cystic fibrosis).
- Blood tests are of limited value although peripheral blood eosinophilia may be present in children with food protein sensitivity. Investigation of immune function may reveal specific abnormalities. Measurement of renal function and electrolytes is particularly important if there is poor fluid balance.
- Radiological studies are rarely useful but barium meal and follow-through will exclude malrotation and may occasionally demonstrate a blind loop.
- Endoscopy of the upper and lower gastrointestinal tract, with biopsies, may be required.
Further reading & references
- Diarrhoea and vomiting in children under 5; NICE Clinical Guideline (April 2009)
- Guandalini S et al; Diarrhea, Medscape, Jun 2012
- The management of acute bloody diarrhoea potentially caused by vero cytotoxin producing Escherichia coli in children, Health Protection Agency (July 2011)
- Webb A, Starr M; Acute gastroenteritis in children. Aust Fam Physician. 2005 Apr;34(4):227-31.
- ESNM12: Acute diarrhoea in children: racecadotril as an adjunct to oral rehydration, NICE (Mar 2013)
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Gurvinder Rull
Dr Colin Tidy
Dr Hayley Willacy