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.

The issue of gastroenteritis in adults and older children is covered elsewhere as they tend to pose different problems and risks from the very young. This article will concentrate on gastroenteritis in young children as older children are more akin to young adults.

The problem is especially marked in small infants. They have little body weight and little reserve from which to loose salt and water. The kidneys may also be less able to concentrate urine.

• 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 more 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. Management is not usually dependent upon cause.

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. Bad water in the developing world is a great risk. A compromised immune system leaves the patient vulnerable to gastroenteritis. Patients with AIDS are especially at risk. Breast feeding affords some protection.²

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. However, most gastroenteritis in children is viral in origin.

Symptoms

In older children, the history may well give an indication of cause. The incubation period for viruses is usually about a day, for bacillary dysentery a few hours to 4 days and for parasites 7 to 10 days. In small children, this is much less likely to be helpful.

• 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 0157 or after return from an exotic location it may be Entamoeba histolytica. Salmonella is also a possibility.
• Pyrexia in adults often suggests an invasive organism as the cause, but 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.³

• 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.

The article on gastroenteritis in adults gives a list of various infective agents and their incubation periods and this will not be repeated here. These incubation periods should not be taken too rigidly. There is enormous variation between different authorities with regard to the incubation period for any given infective agent and it is likely that the incubation period is dependent upon the infecting dose and the resistance of the host. Incubation periods may be shortened in young children.

Not all diarrhoea or vomiting is gastroenteritis, especially in children and other causes must be considered. The following list is far from complete but gives some other causes of diarrhoea or vomiting.

• Urinary tract infection.
• Otitis media.
• Septicaemia.
• Meningitis.
• Constipation with overflow.
• Pneumonia.
• Acute appendicitis (older children) but other conditions can present in a similar way including mesenteric adenitis and malrotation of the gut.
• Intussusception produces a "red current 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.

Diagnosis is often by culturing the organism from the stool. Rotavirus can be detected. Microscopy for ova or parasites. Usually samples are not required but they may be desirable in outbreaks, especially in childcare premises, hospitals, schools and residential institutions.

Both dysentery and food poisoning are notifiable diseases. The laboratory may report the isolation to the relevant authority but it is better to duplicate notification than to overlook it. Notification is a statutory duty.

In the hospital setting, FBC and U&E will be fundamental, but they are not usually required in primary care.

Aims of Management

The aims of management may be summarized as:

• To identify and treat those with moderate to severe dehydration, especially those at high risk who may need referral to hospital.
• To treat or prevent more mild dehydration.
• To educate parents in the management and prevention of gastroenteritis.
• To prevent spread.

Risk stratification

Risk stratification is important.

• Those with mild or no discernable dehydration can readily be managed at home.
• Those with 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.
• Those with 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.
• Anyone with an abdominal mass or undue tenderness or pain needs to be admitted to hospital as it may be a surgical problem.[
  *]If the situation is deteriorating, admit.
• If urine output reduces markedly, dehydration may be rather worse than anticipated but it could also be haemolytic uraemic syndrome. They need admission for assessment.
• If the situation persists for more than 2 weeks, assessment in secondary care is required.
• In small children the threshold for admission to hospital should be low, especially when they are less than 1 month old. Even those up to 6 months old are at greater risk.

Non-drug management

• 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.
• Attention to hand washing to prevent spread to others.

Older children who have gastroenteritis do not wish to eat and there should be no pressure to do so. If appetite has returned and the patient feels hungry, this is a good sign that it is safe to resume food but start with something small and bland.

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.⁴

"Red flags"

• Severe or life-threatening dehydration requires rapid intravenous rehydration with both water and electrolytes.
• Paralytic ileus or marked abdominal distension means that oral fluids will not be absorbed.
• Very rapid stool loss may make it impossible for the patient to meet loss by oral intake. If the situation is deteriorating, admit to hospital.
• Severe, repeated vomiting is unusual. Usually, most of the oral fluid is absorbed despite vomiting, and vomiting stops as dehydration and electrolyte imbalance are corrected.
• 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.⁵ They may be used in the severely ill, especially the immuno-compromised.⁶
• 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.⁷ 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.⁸
• 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.⁹ 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.

General wisdom is that, especially in children, antibiotics, antiemetics, anti-diarrhoeals and anti-spasmodics are all to be avoided. They may have a place at times in hospital practice but they should be avoided in primary care.

• 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.²

The number of deaths from rotavirus in children in England and Wales is probably no more than 3 or 4 a year¹⁰ although it will be much greater in less developed countries and worldwide the number is probably 600,000 to 800,000 a year. There is now an effective rotavirus vaccine available.¹¹ There have been suggestions of increased risk of intussuseption 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