United Kingdom
Change

Support and offers for individual members and customers

Health Information

Gastroenteritis in adults

Published by Bupa's health information team, June 2008.

This factsheet is for adults who have gastroenteritis or who would like information about it. For information on gastroenteritis in children, see Related topics.

Gastroenteritis is an inflammation of the stomach and intestines caused by infection. In the UK, about one in five people are affected by gastroenteritis each year. In most cases, gastroenteritis clears up without the need for specific medical treatment.

About gastroenteritis
Symptoms
Complications
Causes
Diagnosis
Treatment
Prevention
Further information
Questions and answers
Video
Related topics
Sources

About gastroenteritis

The stomach and intestines are known collectively as the gastrointestinal tract - or gut. Gastroenteritis is an infection of the gut. You can get infected from eating or drinking food that is contaminated with bacteria, viruses or parasites, or from other infected people (for more information, see Causes).

Some of these germs can damage the cells lining the inner surface of the gut and interfere with its normal functions.

Certain bacteria or viruses may also produce toxins that irritate the gut and cause it to produce excess amounts of fluid. This can lead to the various symptoms of gastroenteritis such as diarrhoea.

Symptoms

The time between catching the infection and the start of symptoms - the incubation period - depends on the cause of gastroenteritis. Depending on the type of infection, it can range from a few hours to a couple of weeks.

You may have some or all of the following symptoms:

diarrhoea, which may contain blood and mucus, or be watery, greasy or frothy
nausea and vomiting
abdominal cramping, bloating or pain
fever

Most people recover within a week. However, with severe infections, which are uncommon in the UK, the illness may persist for many weeks. It's important to see your GP if your symptoms last for more than a week, or if you have recently travelled abroad.

The symptoms of gastroenteritis may be confused with other conditions, such as irritable bowel syndrome (IBS), Crohn's disease or ulcerative colitits.

Complications

Complications from gastroenteritis occur mainly in the young and the old, in people with chronic gastroenteritis and in those who have weakened immune systems.

Possible complications of gastroenteritis include:

dehydration - this can lead to kidney failure if severe
malnutrition
irritable bowel syndrome

You should contact your GP if:

your pain is severe or doesn't respond to normal painkillers
your vomiting or diarrhoea continues for more than a few days or you can't hold fluids down - this can lead to dehydration
there is blood or mucus in the diarrhoea
you have signs of moderate or severe dehydration, including a very dry mouth, muscle cramps, reduced urine, sunken eyes and, later, confusion or irritability
you have recently travelled abroad
you can't keep down medicines you normally take

Causes

Viruses

Viruses are a major cause of gastroenteritis. These include:

rotavirus
norovirus
enteric adenovirus
hepatitis A

Viral infection can be seasonal and there is a peak of infections with rotaviruses and noroviruses during the winter months.

Bacteria

The most common cause of bacterial gastroenteritis is food poisoning. Food poisoning is caused by different bacteria from different foods, for example:

Salmonella - dairy, eggs and poultry
Campylobacter - dairy, meats and poultry
Bacillus - reheated rice
Vibrio - seafood
Escherichia coli (E. coli) - minced beef

Some E. coli strains are particularly harmful, including E. coli 0157, which produces a toxin that can also damage the kidneys, cause red blood cells to break down and cause inflammation in small blood vessels. These infections can be fatal and children can be particularly vulnerable.

Parasites

Parasites rarely cause gastroenteritis in the UK, but are a major problem in less developed countries and can be caught if you go abroad.

Other causes

Some food allergies, for example an allergy to strawberries, can lead to gastroenteritis.

Diarrhoea can also be caused by other infections such as pneumonia or urinary tract infections. However, very occasionally it may be caused by other conditions such as encephalitis, diabetes, appendicitis or a blockage of the gut.

Some medicines, such as antimalarials, can also cause symptoms of gastroenteritis. Antibiotics can lead to gastroenteritis by killing the normal, healthy bacteria in your gut.

How is gastroenteritis spread?

The infections are transmitted:

in contaminated food
from person to person - this happens if an infected person goes to the toilet and doesn't wash their hands properly afterwards, before handling food or touching other people
if an individual infected with a virus sneezes or coughs, as another person could inhale a virus
in shellfish harvested in polluted waters
in contaminated drinking water - the majority of infections are carried this way in the developing world but can also affect travellers

Diagnosis

Your GP will ask you about your symptoms and examine you. He or she may also ask about your medical history. He or she may also ask you for a faeces (stool) sample to send for laboratory testing.

If you have been travelling, your GP will ask you which countries you have visited and which vaccinations you have had.

Treatment

Self-help

Most cases of gastroenteritis can be treated at home.

The most important aspect of treatment is to replace the fluids and salts you have lost, to prevent dehydration.

If you have a mild case of gastroenteritis, your usual daily drinks (water, squash) should be enough. You can continue to eat normally, but you shouldn't have fatty foods or food or drinks that have lots of sugar.
If you have a more severe infection, use an oral re-hydration solution (eg Dioralyte), which you can buy in pharmacies. These are usually a powder that is made up into a solution by adding water. They contain the right balance of sugars and salts for your body and they encourage re-hydration. You should eat foods high in carbohydrates such as rice or toast until you can take solid food and return to a normal diet.

Probiotics (foods containing live, beneficial bacteria) can help to reduce the duration of diarrhoea.

Medicines

Medicines to stop diarrhoea such as loperamide (eg Imodium) are only recommended for adults. These medications slow down movement in the intestines, but have no effect on the excess fluid in the intestines, so it will come out later. They can also cause side-effects such as tummy cramps, dizziness and skin reactions.

If you are in pain, take the painkiller that you would normally take for a headache. Follow the instructions in the patient information leaflet that comes with the medicine and ask your pharmacist for advice.

Your GP may prescribe an antisickness medicine (anti-emetic). Vomiting normally stops when you have drunk enough fluid, but anti-emetics can be helpful if you have severe vomiting. Many anti-emetics are also sedatives, so it's advisable not to drive or use machinery after taking them.

Most cases of gastroenteritis are caused by viruses, which are not treatable with antibiotics. Your GP won't usually prescribe antibiotics for gastroenteritis.

However, if your GP suspects that you have a bacterial infection, he or she may ask you for a stool sample to send for laboratory testing. This is more common if you have been travelling recently. The results will help to determine which antibiotic to treat you with.

Hospital treatment

If you have lost so much fluid that you are very dehydrated, hospital treatment may be needed to replace fluids directly into your bloodstream (intravenously).

Prevention

The best way to prevent gastroenteritis is to always wash your hands with soap after going to the toilet and to disinfect toilets after use.

You should also practise good food hygiene.

Before travelling make sure you have had any vaccinations required and use bottled water if necessary when abroad.

If you have gastroenteritis, help to prevent spreading the infection to other family members by:

hygienically disposing of, or properly cleaning, all soiled items such as towels
cleaning the toilet with disinfectant
not sharing towels and flannels
not preparing food for others

If you have gastroenteritis you may be infectious to others. You should stay away from work, school or college for at least 48 hours after your symptoms have stopped.

Further information

Health Protection Agency
www.hpa.org.uk
Food Standards Agency
www.foodstandards.gov.uk