Childhood diarrhoea

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, and 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.¹ 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 the separate article Gastroenteritis in Children.

Acute childhood diarrhoea

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 childhood diarrhoea

• Gastroenteritis:

  • 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, cow's 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 children²

Bloody childhood diarrhoea should arouse suspicion of bacterial infection. In developed countries, bloody diarrhoea in children, when due to acute enteric infection, is usually caused by either Campylobacter spp. (mainly Campylobacter 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.

In Africa, outbreaks of Ebola virus primarily occur in remote villages close to tropical rainforests in Central and West Africa. Confirmed cases of Ebola haemorrhagic fever were reported in the Democratic Republic of the Congo (DRC, formerly Zaire), Sudan, Gabon, Uganda, Republic of Congo, Côte d'Ivoire and for the first time in Guinea, Liberia and Sierra Leone in 2014. The 2014 Ebola outbreak was one of the largest Ebola outbreaks in history and the first in West Africa.

• Infants aged up to 1 year:
  

  • Common: intestinal infection, infant colitis (nonspecific colitis, breast-milk colitis, cow's 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.

Childhood diarrhoea symptoms

• 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 traveller's diarrhoea.

• Animal exposure: for example, exposure to young dogs or cats is associated with Campylobacter spp.

Signs

• 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.³ See also the separate article 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 will need further assessment (usually urgent hospital admission for possible appendicitis).

Investigations

• 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.

• Full blood count: white cell count is usually normal but may be raised in some bacterial infections.

• Urea and electrolytes.

• Liver function tests: 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.

Childhood diarrhoea treatment⁴

See also the separate Gastroenteritis in Children and Dehydration in Children articles.

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 6 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 6 months. Small amounts of fluid given frequently are often tolerated, even when vomiting has been a prominent symptom. The most important factor in treatment is to maintain hydration.

Breastfeeding

Continued use of breast milk has been shown to be beneficial in children with acute diarrhoea.

Antibiotic therapy

This 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.

• Where there are signs of dehydration, especially if aged under 6 months.

• If there is inability to comply with oral rehydration - eg, vomiting, poor social circumstances.

• Where there is a pre-existing medical condition which may worsen with diarrhoea (eg, diabetes).

Complications

• Rotavirus infection and infection with giardia may result in temporarylactose 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 reactive arthritis.

• 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.

Prognosis

• 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.

Childhood diarrhoea prevention

• 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 was available from September 2013. Rotarix® is administered orally at 2 and 3 months of age.⁵ It has made a significant impact. 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. Since 2020 an Ebola vaccine has been available. This has been successfully used to manage disease outbreaks in the Democratic Republic of the Congo and in Guinea.⁶

Chronic childhood diarrhoea

Diarrhoea lasting for more than two weeks, particularly if associated with weight loss, needs further investigation.

Differential diagnosis

• 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.

  • Breastfed babies often have liquid and apparently 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 or failure to thrive:
  

  • Food intolerance - eg, cow's 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, G. lamblia.

  • Chronic enteric infection: stagnant loop syndrome.

  • Iatrogenic: therapeutic diets, drugs (eg, excessive laxatives).

  • Miscellaneous: eg, acrodermatitis enteropathica, immunodeficiency, Shwachman-Diamond syndrome, hyperthyroidism.

Investigations

• 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 urea 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.

• The National Institute for Health and Care Excellence (NICE) recommends the use of faecal calprotectin testing to help exclude inflammatory bowel disease and may obviate the need to subject the patient to endoscopy.⁷