Inflammation of the lining of the stomach and intestines, usually due to infection
- Most common in babies and children but can occur at any age
- Poor food hygiene or unsanitary conditions are risk factors
- Gender and genetics are not significant factors
Gastroenteritis usually starts suddenly, with symptoms of vomiting, diarrhoea, and fever. Outbreaks commonly occur within families and among people who are in close contact, such as schoolchildren. Most people recover from the disorder without problems, but gastro-enteritis may be serious in elderly people and very young children (see Vomiting and diarrhoea) because there is a risk of dehydration. In developing countries, gastroenteritis is a common cause of death in these age groups.
What are the causes?
Gastroenteritis is usually due to a viral or bacterial infection that irritates the lining of the stomach and intestines. The infection may be acquired from contaminated food or water (see Food poisoning), or it may be spread among people who are in close contact, especially if hygiene is poor.
Viral gastroenteritis is often caused by rotaviruses or astroviruses, particularly in young children, and by noroviruses in older children and adults. Most people acquire immunity to these viruses by the time they are adults. Bacterial causes of gastroenteritis include salmonella, campylobacter, and Escherichia coli.Escherichia coli.
What are the symptoms?
The symptoms of gastroenteritis often develop rapidly over 1–2 hours and may vary in severity. They include:
Nausea and vomiting.
Cramping abdominal pain.
Fever, often with headache.
In some people, vomiting or diarrhoea may lead to dehydration. Babies and elderly people are much more susceptible to the effects of dehydration, which are often difficult to recognize. Babies may become listless and cry feebly, and an elderly person may become confused. Consult your doctor promptly if you are not able to keep fluids down or have not passed urine for over 6 hours, especially if you have a long-term illness, such as diabetes mellitus or kidney disease. Without appropriate treatment, dehydration may be life-threatening.
What might be done?
A mild attack of gastroenteritis usually clears up without treatment, but you should follow self-help measures and drink plenty of fluids every few hours (see Preventing dehydration). Over-the-counter antidiarrhoeal drugs are useful if you need to relieve your symptoms quickly. However, these treatments are best avoided because they may prolong gastroenteritis by retaining the infective organism inside the gastrointestinal tract.
If your symptoms are severe or prolonged, you should consult your doctor. You may be asked to provide a sample of faeces, which will be tested for infection. Antibiotics are rarely given unless a bacterial infection is identified. Severe dehydration requires emergency treatment in hospital to replace fluids and salts intravenously.
What is the prognosis?
Most people recover rapidly from gastroenteritis with no long-lasting effects. Occasionally, short-term damage to the intestine may reduce its ability to digest lactose, the natural sugar present in milk (see Lactose intolerance). This disorder occurs particularly in infants and often results in diarrhoea that can persist for days or weeks. In rare cases, gastroenteritis may trigger irritable bowel syndrome.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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