Sudden nausea, vomiting and diarrhoea – gastroenteritis can be really nasty. Fortunately, it is generally harmless and quickly passes. Prevention? Treatment? An overview of the most important information.
Gastroenteritis, or stomach flu as it is sometimes referred to, has nothing to do with classic flu. It is an inflammation in the gastrointestinal tract. The culprits are usually viruses or bacteria. Gastro-intestinal infections occur very frequently. This is especially true among children and when travelling. Typical symptoms include nausea, stomach cramps, vomiting and acute diarrhoea. The symptoms strike suddenly and can be very severe depending on the trigger – our immune system wants to get rid of the disease-causing intruders as quickly as possible.
Viruses are almost always responsible for the infection. In the case of babies and small children, rotaviruses are the most common pathogens, followed by highly contagious noroviruses. Both viral infections lead to heavy diarrhoea, usually combined with projectile vomiting.
Bacterial infections are rarer but more persistent. They last longer and cause severe cramps and intensive diarrhoea or diarrhoea with vomiting, sometimes with a high fever. The most common bacterial pathogens are Salmonella, Campylobacter, Yersinia, Shigella and pathogenic strains of the intestinal bacterium Escherichia coli, usually referred to as E. coli for short. Infection occurs via unclean water and contaminated food (e.g. raw meat) as well as through contact with faeces or animals.
Where parasites are the trigger, this usually comes after trips to countries with low hygiene standards.
In rare cases, COVID-19 can cause symptoms that are similar to those of a stomach flu. If you are experiencing symptoms such as nausea, vomiting, diarrhoea or abdominal pain, stay at home. Get tested for coronavirus or call your doctor to discuss what to do next. Even if your COVID-19 test result is negative, you should avoid contact with other people for at least 24 hours after your symptoms have disappeared.
People contract gastroenteritis as a result of so-called faecal-oral smear infection, i.e. through contact with traces of faeces that enter the mouth via your hand or via contaminated objects or food. The key to preventing gastroenteritis is thus to wash your hands with soap. Generally speaking, you should ensure good hygiene in your kitchen and home.
A viral infection subsides by itself within two or three days. It is important to drink a lot in order to replenish the body’s lost fluids and minerals. Healthy adults can temporarily cope well with a fluid deficit, but still feel weak. For weakened, older people and children, however, dehydration can be dangerous. You should therefore look out for its signs (see also the section “When to go to the doctor?”).
Make sure you take in enough fluids: at least 1.5 to 2 litres per day during the acute phase. The most tolerable liquids for your stomach are still water, herbal tea and bouillon. Bouillon also replenishes your body’s lost electrolytes. Do not have any sweetened drinks such as fruit juices, energy drinks, coffee and alcohol – they only irritate your stomach and intestines even more.
Electrolyte solutions are appropriate for young children, older people and those suffering from severe diarrhoea. The ready-made solutions contain the right quantities of dextrose, salts and minerals to make up for the lack of water and salt. They can be found in pharmacies as a powder that is ready to mix with water. Or you can make your own electrolyte solution:
Mix 4 teaspoons of sugar, ¾ of a teaspoon of table salt and 1 cup of orange juice with 1 litre of still water or mineral water (tap water can be contaminated with bacteria in some countries). How much to drink: 40 millilitres per kilogram of bodyweight each day. Example: A person weighing 75 kilograms should drink 3 litres over the entire day.
Also give your body a lot of rest. Physical exertion is taboo – your immune system already has enough to do with fighting the pathogen in your intestines.
During the initial acute phase of gastroenteritis, not eating is a sensible course of treatment. However, make sure to avoid hypoglycaemia. Start with light food as soon as you feel hungry again or your appetite comes back. The following foods are gentle on the stomach and intestines – make sure to always chew well!
Avoid fats and fibres such as those found in sausages, cheese, milk, wholemeal bread, muesli, fruit and raw vegetables. You should also give heavily seasoned, sweet or flatulence-inducing food and coffee a miss for the time being. Pay attention to what does you good – and expand your diet step by step.
Heat: A hot water bottle or cherry-stone cushion placed on your abdomen soothes the pain and cramps.
Healing clay: This fine sand with minerals and trace elements is helpful in combating diarrhoea as it binds with fluids and toxins. It is available at pharmacies and chemist’s shops as a powder or capsules.
Ginger: The spice bulb can reduce the duration and severity of vomiting in children. Ginger is also good for adults. Recipes can be found in the blog article on ginger.
Gastrointestinal tea: Fruits and medicinal herbs such as blueberries, camomile, fennel, aniseed and caraway soothe the gastrointestinal tract and relieve your symptoms. You can purchase them as ready-made preparations or mix them yourself.
Activated carbon: The carbon particles of the medical activated carbon have a large surface area, meaning that bacterial toxins, organic substances and the pathogens are picked up by them and eliminated. Ask for advice at your pharmacy.
Prolonged diarrhoea indicates the presence of aggressive germs. In such cases, a medical check-up is required in order to identify the specific trigger of the infection. Contact your doctor in the following situations:
Gastroenteritis is triggered by a gastro-intestinal infection caused by bacteria, viruses or parasites. It can be passed on from one person to another. Irrespective of the pathogen, the stools and vomit of the ill individual are highly infectious. Clean hand hygiene is essential.
In the case of bacterial gastroenteritis, the germs come from unclean water and contaminated food such as raw cold meats, raw eggs, poultry and raw milk products.
Generally speaking, gastroenteritis is harmless and no medication is required. While the frequent emptying may be tedious, this is the only way that the pathogens can leave your body. If the diarrhoea (and vomiting) lasts for longer than three days, however, a medical check-up is required in order to clarify the causes. In the case of bacterial gastroenteritis, those affected may have to take medication, i.e. antibiotics, against the pathogens on a targeted basis.
In the past, cola and pretzel sticks were viewed as household remedies to combat gastroenteritis. However, this is not very advisable – for children, cola is completely inappropriate: the high volume of sugar can make the diarrhoea worse and the caffeine deprives the body of extra potassium. Rusk or bananas are more preferable. Further information in this regard can be found in the section “What should you eat when you have gastroenteritis?”
Food poisoning has similar symptoms to gastroenteritis. In the case of a gastrointestinal virus, however, these symptoms occur individually – not everyone affected will necessarily vomit, for example. Food poisoning typically involves a group of people all falling ill at the same time, for instance at a retirement home. In contrast, a gastro-intestinal illness usually only affects one person. The specific pathogen and thus a diagnosis can only be determined on the basis of a laboratory test of faecal samples and the contaminated food.
This depends on what triggers it. Those affected excrete the largest quantities of pathogenic germs as soon as the acute symptoms occur. Other people can then become infected with the germs if, for example, they come into contact with the vomit or stools. However, the pathogens can still be excreted and infect others days or even weeks after the symptoms have subsided.
Depending on the pathogen, the time from infection to the appearance of the first symptoms (incubation period) is one to seven days. In the case of noroviruses or Salmonella, gastroenteritis can break out in as few as six hours. For the bacterium Campylobacter, this can take up to five days.
Peter Bauerfeind is Head of the Gastroenterology/Hepatology department at Triemli Hospital and a member of the board of directors of the Swiss Gastrointestinal League. He also has long-standing experience in the field of endoscopy. Peter Bauerfeind was available to the editorial team in an advisory and editorial capacity for this article.
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