Gastroenteritis in Adults

What is gastroenteritis and what causes it?

Gastroenteritis is an infection of the gut (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.
• A high temperature (fever) and headache sometimes occur.

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

Symptoms of dehydration

Diarrhoea and vomiting may cause dehydration (a lack of fluid in the body). Consult a doctor quickly if you suspect you are becoming dehydrated. Mild dehydration is common and is usually easily and quickly reversed by drinking lots. Severe dehydration can be fatal unless quickly treated because the organs of the body need a certain amount of fluid to function.

• Symptoms of dehydration in adults include: apathy, tiredness, dizziness, headache, muscular cramps, pinched face, dry mouth and tongue, sunken eyes, passing little urine, a dry mouth and tongue, sunken eyes, weakness and being irritable or lethargic.
• Symptoms of severe dehydration in adults include profound apathy, weakness, confusion, coma and greatly reduced amount of urine. This is a medical emergency.

Dehydration in adults is more likely to occur in:

• Elderly or frail people.
• People with severe diarrhoea and vomiting. In particular, if you are not able to replace the fluid lost with sufficient drinks.

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. (Note: if you suspect that you are dehydrated, you should contact a doctor.)

• 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 mildly to moderately dehydrated.

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. People with certain conditions should not take loperamide. Therefore, read the leaflet that comes with the medicine to be safe. For example, pregnant women should not take loperamide.

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

If symptoms are severe, or persist more than several days, 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.

Are there any complications that may occur from gastroenteritis?

Complications are uncommon in the UK. They 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. Some people who become severely dehydrated need a 'drip' of fluid directly into the vein.
• 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 develops, 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.

Other advice

If you have gastroenteritis, the following are also recommended:

• 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. Ideally, use liquid soap in warm running water, but any soap is better than none. Dry properly after washing.
• Don't share towels and flannels.
• Do not prepare food for others.
• In general, it is often advised that people with gastroenteritis should not swim in swimming pools for two weeks after the last episode of diarrhoea.
• Stay off work, college, etc until until at least 48 hours after the last episode of diarrhoea or vomiting.
• Food handlers: if you work with food and develop diarrhoea or vomiting you must immediately leave the food-handling area. For most, no other measures are needed, other than staying away from work until at least 48 hours after the last episode of diarrhoea or vomiting. Some special situations may arise. For example, if diarrhoea is due to hepatitis A infection, then you should remain off work until seven days after the onset of symptoms (that is, of jaundice or diarrhoea). Specialist advice may be needed for some uncommon causes of gastroenteritis. If in doubt, seek advice from your employer or GP.

Can gastroenteritis be prevented?

The advice given in the previous section is mainly aimed at preventing the spread of infection to other people. However, even when we are not in contact with someone with gastroenteritis, proper storage, preparation and cooking of food, and good hygiene help 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).

The simple measure of washing hands regularly and properly is known to make a big difference to the chance of developing gastroenteritis.

You should also take extra measures when in countries of poor sanitation. For example, avoid water and other drinks that may not be safe, and avoid food washed in unsafe water.