Gastroenteritis (gastro)

What is gastroenteritis?

Gastroenteritis is a common condition that affects the gut (the stomach and intestines) and is often highly infectious. It is also known as ‘gastro’.

Gastro is triggered by infection that causes inflammation of the lining of the digestive system. It can cause vomiting, diarrhoea, stomach pain and nausea.

Gastro is not usually serious, but it can lead to dehydration. Milder forms can be managed at home by drinking fluids. However, older people, young children and those with a weakened immune system are at risk of developing more serious illnesses.

What are the symptoms of gastroenteritis?

If you have gastroenteritis, you may have:

• vomiting
• diarrhoea
• nausea (feeling sick in the stomach)
• stomach pains
• fever
• headaches
• no appetite

Gastroenteritis symptoms usually last for 1 to 2 days, but occasionally they may persist for as long as 10 days.

When should I see my doctor?

See a doctor immediately if your child cannot keep down a sip of liquid or has dehydration (dry mouth, no urine for 6 hours or more, or lethargy). Babies under 6 months should always be seen by a doctor if they have gastro.

Adults and older children should seek medical advice if their symptoms include a fever, severe abdominal pain, blood in their diarrhoea or signs of dehydration, such as thirst and decreased urination, lethargy, dry mouth, sunken eyes or feeling faint when standing.

What causes gastroenteritis?

Gastro may be caused by:

• viruses (these are by far the most common cause and include the rotavirus and norovirus infections)
• bacteria, such as salmonella
• toxins produced by bacteria
• parasites, such as giardia
• chemicals, such as toxins in poisonous mushrooms

Viral gastroenteritis is highly infectious and spreads through contact with contaminated hands, objects or food. It can also be spread through coughing and sneezing.

How is gastroenteritis diagnosed?

A doctor can diagnose gastro after talking to and examining you. If you’re not getting better, the doctor may want to do a stool (poo) test to find out what organism is making you ill.

How is gastroenteritis treated?

Gastro should only last for a few days and does not normally require treatment. Medication for nausea or diarrhoea can be useful for adults, but may not be safe for children. Antibiotics are rarely helpful.

The most important treatment for gastroenteritis is to drink fluids. Frequent sips are easier for young children than a large amount all at once. Keep drinking regularly even if you are vomiting. You can also buy rehydration fluids from a pharmacy. These are the best fluids to use in cases of gastro, especially for children.

Try to eat small amounts of food often if you feel nauseous. When your appetite returns, start with bland, easy-to-digest foods, such as plain crackers, toast, bananas, rice and chicken.

Avoid milk and other dairy products as well as undiluted fruit juice, soft-drinks, or sports drinks because the sugar may make the diarrhoea worse. It is fine to eat once you feel like it.

If you are very sick with gastro, you may need to go to hospital where you may be given fluids directly through a vein (a “drip”).

Babies and children with gastro

If you have a baby under 6 months, they should be checked by a doctor. It’s also a good idea to have babies older than 6 months and young children with gastro checked by a doctor in case they are dehydrated.

If you cannot find rehydration fluids, or your child refuses to drink it, giving diluted fruit juice (1 part juice to 4 parts of water) is reasonable. You could try a cube of ice or an ice-block if your child won’t drink.

Babies can continue milk feeds throughout the illness, with rehydration fluid between feeds.

Can gastroenteritis be prevented?

Gastro can be spread very easily. You might get it from having contact with an infected person (or their vomit or poo). It can also spread via contaminated food or water.

It’s important to stay home, away from work, school or childcare, until 48 hours after the last episode of vomiting or diarrhoea.

To reduce your risk of catching or spreading gastro, wash your hands well after using the bathroom or changing nappies, and before eating or preparing food.

If you are travelling to places where the local tap water is not safe to drink, only use bottled water for drinking and brushing your teeth; don’t put ice in drinks; only eat fruit you can peel yourself; and avoid uncooked food, including salads.

Children and vaccination for rotavirus

Rotavirus is a virus that causes severe gastroenteritis in babies and young children. All young children should receive the rotavirus vaccine at 6 weeks and 4 months of age. A third dose at 6 months may be needed depending on the brand of vaccine used.

This vaccine is effective in preventing the rotavirus infection in about 7 out of every 10 children vaccinated. It is also effective in preventing severe gastroenteritis in about 9 out of every 10 infants vaccinated. The vaccine provides protection for up to 5 years.