Gastroenteritis in Children

Gastroenteritis is a non-specific term used to describe a condition in which there is a combination of nausea, vomiting, diarrhoea and abdominal pain. The term is usually taken to mean those of infectious origin.

Although gastroenteritis is usually self-limiting in small infants it can have deleterious consequences as a result of lower body weight and little reserve from which to lose salt and water. The kidneys may also be less able to concentrate urine.

Also see articles on gastroenteritis in adults and older children, traveller's diarrhoea, salmonella gastroenteritis and childhood diarrhoea.

• Gastroenteritis is caused by a variety of viral, bacterial, and parasitic pathogens.
• In the UK, 204 of every 1,000 consultations for children under 5 years old are for gastroenteritis with 7 of every 1,000 being admitted to hospital.¹ The peak age is between 6 months and 2 years.
• Worldwide, there are about 2 million deaths per year from gastroenteritis in children under 5 years old.
• Virus infections, especially rotavirus, cause about 70% of cases in children under 5 in the UK. The causative agent for most cases of gastroenteritis is never isolated and the responsible agent never diagnosed.

Norovirus is gaining in importance but overall, irrespective of age, rotavirus identification is still about 4 times as common.

Risk factors

• Poor hygiene and lack of sanitation increase the incidence e.g. bad water in the developing world.
• Compromised immune system e.g. AIDS.

Infection may arise from poorly cooked food, cooked food that has been left too long at room temperature or from uncooked food. Insufficient reheating of food not only fails to kill bacteria, but may speed up multiplication and increase the bacterial load ingested. Even if reheating of cooked food kills bacteria, enterotoxins such as staphylococcal exotoxin, are not destroyed.

Symptoms

• Epidemics in this country are usually caused by a rotavirus but norovirus is a common cause of "winter vomiting".
• Ask about recent travel abroad.
• Are other members of the family affected?
• In small children, ask about the frequency of wet nappies to assess urine output.
• Antibiotics may cause Clostridium difficile colitis.
• If diarrhoea lasts for more than a fortnight, the aetiology is likely to be parasitic or non-infectious.
• Bloody diarrhoea should arouse suspicion of bacterial infection, especially E. coli O157 or salmonella.
• Children are often febrile with any type of infective gastroenteritis.

Most children do not become significantly dehydrated but if diarrhoea and vomiting are very frequent, they are most at risk. Very young babies are also at risk.

Signs

Assessment is based largely on estimating the degree of dehydration so as to stratify risk. There is a tendency to overestimate the degree of dehydration. Poor capillary refill, loss of skin turgor and absence of tears are important signs.²

• Those with mild dehydration and loss of body weight of less than 5% will probably have no abnormal signs and are not at risk. Capillary refill is normal as is skin turgor and the child is alert, active and drinking well.
• Moderate dehydration with loss of body weight between 5 and 9%, is likely to produce some positive signs. These may include at least 2 of:
  • Restless
  • Irritable
  • Sunken eyes
  • Thirst and drinking eagerly
• Severe dehydration with loss of 10% or more of body weight is likely to produce at least 2 of:
  • Abnormally sleepy
  • Sunken eyes
  • Lethargy
  • Drinking poorly
• Pinch up the skin and see how it returns to its position. Normally it does so immediately and will do so in mild dehydration. It will take longer but less than 2 seconds in moderate dehydration. If it takes 2 seconds or more, this implies severe dehydration.
• If there are signs of shock with a weak, thready pulse and cold periphery, this is serious and implies severe dehydration.

In children of less than 18 months old, it may be possible to feel the tension of the anterior fontanelle.

Always perform an abdominal examination and record your findings, even if negative. Do not be slow to repeat examination if the situation changes.

• Is there undue tenderness?
• Is there a mass?
• If the abdomen is distended, listen for bowel sounds.

Not all diarrhoea or vomiting is gastroenteritis, especially in children and other causes must be considered and includes the following:

• Occult infection e.g. urinary tract infection, otitis media, meningitis, pneumonia.
• Constipation with overflow.
• Acute appendicitis (older children) but other conditions can present in a similar way including mesenteric adenitis and malrotation of the gut.
• Intussusception produces a "redcurrant jelly" stool but the parents may report this as bloody diarrhoea.
• Coeliac disease.
• Parents often use the words "projectile vomiting" inappropriately but the age of children with pyloric stenosis is characteristic and the force of the vomit in such cases is most impressive.
• Babies may be getting regurgitation, possetting or even gastro-oesophageal reflux.
• Diabetic ketoacidosis.
• Addison's disease.

• Stool samples - for microscopy (include ova, cysts and parasites), culture and sensitivity. Usually samples are not required but they may be desirable in outbreaks e.g. in schools.
• Blood tests - FBC and U&E for patients in the hospital setting.
• Other tests will depend on the individual case e.g. abdominal imaging.

Dehydration

• Mild or no discernable dehydration - can readily be managed at home.
• Moderate dehydration - can probably be managed at home but a number of issues need to be considered including the social situation and the ability of the parents to cope.
• Severe dehydration - will probably need intravenous rehydration and will have to be admitted to hospital; anyone in shock needs to be admitted as a matter of urgency.
• Attention to dehydration usually requires just oral rehydration fluids. Starvation is recommended but feeding should be introduced in children as soon as vomiting subsides. Breast feeding should not be stopped.
• Oral rehydration is successful in at least 95% of cases but there are danger signs that indicate that intravenous therapy is required and this means admission to hospital. A Cochrane review found no great difference in efficacy between oral and IV rehydration although the former was more likely to lead to paralytic ileus and the latter may have complications from venous access.³
• Glucose malabsorption is unusual but in such rare cases, stool volume will increase and the stool contains large amounts of glucose. This will worsen dehydration.

Drugs

• In most types of gastroenteritis, antibiotics do not shorten the illness but may prolong the carrier stage.⁴ They may be used in the severely ill, especially the immuno-compromised.⁵
• Notable exceptions, where antibiotics are indicated are:
  • Diarrhoea and vomiting with septicaemia
  • Cholera
  • Shigella
  • Giardiasis
  • Amoebiasis
  • Enteric fever (typhoid fever)
• A Cochrane review found very poor evidence of benefit from antiemetics in children and adolescents.⁶ The 2 drugs examined were ondansetron and metoclopramide although the latter is usually avoided in children, adolescents and young adults because of extrapyramidal effects.
• Avoid anti-diarrhoea or anti-spasmodic drugs.
• There may be a place for probiotics in the future but the current position is unclear.⁷
• Several large studies from developing countries, have shown zinc supplementation to be effective in reducing the duration and severity of diarrhoea in children with acute gastroenteritis, as well as the likelihood of recurrence.⁸ The World Health Organisation recommends zinc supplementation (10-20 mg/d for 10-14 d) for all children younger than 5 years with acute gastroenteritis. There is little data to support this from developed countries.

• Infants and those with immunological compromise are more likely to have more severe disease and to require admission to hospital for rehydration. In severe cases, hypovolaemic shock and even death can occur.
• Haemolytic uraemic syndrome is a serious complication that may present with lack of urine output.
• Loss of lactase from the gut, causing lactose intolerance may occur, especially after viral infection. This is quite common but usually not a problem. If it does cause persistent diarrhoea, avoidance of lactose containing food for 4 to 6 weeks will result in spontaneous resolution.

Usually there is uneventful recovery. Risk is greatest at the extremes of life and with immune compromise. In England and Wales in 2005, deaths associated with gastrointestinal infections were predominantly in the elderly.

Breast feeding confers some protection against gastroenteritis, this is especially important in developing countries.⁹

The number of deaths from rotavirus in children in England and Wales is probably no more than 3 or 4 a year although it will be much greater in less developed countries and worldwide the number is probably 600,000 to 800,000 a year.¹⁰ There is now an effective rotavirus vaccine available.¹¹ There have been suggestions of increased risk of intussusception following vaccination but these have not been confirmed. There are no apparent plans to introduce the vaccine to the standard children's schedules in the UK but it may be beneficial when there is HIV in children.¹²