Gastroenteritis in Adults

What is gastroenteritis and what causes it?

Gastroenteritis is an infection of the guts (intestines). The severity can range from a mild tummy upset for a day or two with some mild diarrhoea, to severe diarrhoea and vomiting for several days or longer. Many viruses, bacteria, and other microbes (germs) can cause gastroenteritis.

• A virus is a common cause in the UK. Sometimes it is just 'one of those germs going about'. Viruses are easily spread from one person to another by close contact, or when an infected person prepares food for others.
• Food poisoning (infected food) causes some cases of gastroenteritis. Many different types of germs can cause food poisoning. Common examples are bacteria called campylobacter and salmonella.
• Water contaminated by bacteria or other germs is a common cause, particularly in countries with poor sanitation.

What are the symptoms of gastroenteritis?

• The main symptom is diarrhoea, often with vomiting as well.
• Crampy pains in the abdomen (tummy) are common. Pains may ease for a while each time some diarrhoea is passed.
• High temperatures (fever) and headaches are common.

If vomiting occurs, it typically lasts only a day or so. Diarrhoea often lasts for several days or more and often continues after the vomiting stops. Loose stools (loose faeces) can persist for a week or so before a normal pattern returns. Sometimes the symptoms last longer.

Proper storage, preparation and cooking of food, and good hygiene helps to prevent gastroenteritis. In particular, always wash your hands:

• After you go to the toilet.
• Before you touch food.
• Between handling raw meat and food ready to be eaten. (There may be some bacteria on raw meat.)
• After gardening.
• After playing with pets (healthy animals can carry certain harmful bacteria).

If you have gastroenteritis, the following are also recommended until symptoms go.

• Regularly clean the toilets that you use. Wipe the flush handle and toilet seat with disinfectant (such as household bleach) after each time you use the toilet.
• Wash your hands thoroughly after going to the toilet. Don't share towels and flannels.
• Do not prepare food for others.
• Stay off work until symptoms go. If you work with food ('food handlers') or work as a health carer you should stay off work until you have had no diarrhoea or vomiting for 48 hours.

What is the treatment for gastroenteritis in adults?

Symptoms often settle within a few days or so as the immune system usually clears the infection. The following are commonly advised until symptoms ease.

Fluids - have lots to drink
The aim is to prevent dehydration (low body fluid), or to treat dehydration if it has developed.

• As a rough guide, drink at least 200 ml after each bout of diarrhoea (after each watery stool).
• This extra fluid is in addition to what you would normally drink. For example, an adult will normally drink about two litres a day, but more in hot countries. The above '200 ml after each bout of diarrhoea' is in addition to this usual amount that you would drink.
• If you vomit, wait 5-10 minutes and then start drinking again, but more slowly. For example, a sip every 2-3 minutes, but making sure that your total intake is as described above.
• You will need to drink even more if you are dehydrated. A doctor will advise on how much to drink if you are dehydrated. For example, this may be to drink 1-2 litres over 6 -12 hours if you are mild to moderately dehydrated.

Rehydration drinks are the ideal drink to have. They are made from sachets that you can buy from pharmacies. (The sachets are also available on prescription.) You add the contents of the sachet to water. Rehydration drinks provide a perfect balance of water, salts, and sugar. They are better than just drinking water alone. The small amount of sugar and salt helps the water to be absorbed better from the gut into the body. They do not stop or reduce diarrhoea, but are the best drinks to prevent or treat dehydration.

Do not use home made salt/sugar drinks as the quantity of salt and sugar has to be exact. If rehydration drinks are not available, then have water as your main drink. Also, have some diluted fruit juice now and then as this contains a little bit of sugar. It is best not to have drinks that contain a lot of sugar such as cola, pop or undiluted juice.

Eat as normally as possible
It used to be advised to 'starve' for a while, but this is now known to be wrong. However, you may not feel like food and most adults can do without food for a few days (but don't stop drinking). Eat as soon as you are able.

Medication
Anti-diarrhoea drugs are not usually necessary. However, you may wish to reduce the number of trips to the toilet. You can buy anti-diarrhoea drugs from pharmacies. The safest and most effective is loperamide. The adult dose of this is two capsules at first. This is followed by one capsule after each time you pass some diarrhoea up to a maximum of eight capsules in 24 hours. It works by slowing down the gut's activity. Note: do not give anti-diarrhoea drugs to children under 12 years. Also, do not use anti-diarrhoea drugs if you pass blood with the diarrhoea.

Paracetamol or ibuprofen are useful to ease a high temperature or headache.

If symptoms are severe, or persist, a doctor may ask for a sample of the diarrhoea. This is sent to the lab to look for infecting germs (bacteria, parasites, etc). Sometimes an antibiotic or other treatments are needed, depending on the cause of the infection.

What about probiotics?

Some research studies suggest that taking probiotics may reduce the duration of diarrhoea by about one day. Probiotics are dietary supplements of 'good, non-harmful' bacteria or yeasts. The theory is that these 'good' bacteria and yeasts multiply in the gut and protect the gut from the 'bad' infecting bacteria or virus. Probiotics are not available on NHS prescription. If you wish to try them you can buy them at supermarkets and other stores. Probiotics are sold as capsules, yoghurt products, etc. There is no evidence to prefer any particular form, strength, or dose.

Are there any complications that may occur from gastroenteritis?

Complications are uncommon in the UK and include the following:

• Dehydration and salt (electrolyte) imbalance in the body. This is the most common complication. If you drink plenty of fluids then it is unlikely to occur, or is only likely to be mild and soon recover as you drink. Symptoms of dehydration include: passing little urine, a dry mouth and tongue, sunken eyes, weakness, drowsiness, cool hands or feet. Severe dehydration can be fatal as the main organs of the body need a certain amount of water to function. Some people who become severely dehydrated need a 'drip' of fluid directly into the vein. This is more common in elderly and frail people who are more at risk of dehydration.
• Reactive complications. Rarely, other parts of the body 'react' to an infection that occurs in the gut. This can cause symptoms such as arthritis, skin inflammation, eye inflammation (conjunctivitis and uveitis).
• Spread of infection to other parts of the body. This is rare.
• Persistent diarrhoea syndromes may rarely develop.
• Irritable bowel syndrome is sometimes triggered by a bout of gastroenteritis.

See a doctor if any of the following develop, or if any other symptoms occur that you are concerned about.

• If you suspect that you are dehydrating.
• Blood in the diarrhoea.
• Vomiting for more than 1-2 days, or diarrhoea that does not start to settle after 3-4 days.
• Pains that are getting worse.
• Drowsiness or confusion.
• Infections caught abroad.

Admission to hospital is sometimes needed if symptoms are severe, or if complications develop.

© EMIS and PIP 2006   Updated: September 2006   PRODIGY Validated