Gastroenteritis in adults
Gastroenteritis is inflammation or irritation of the stomach and intestines. It can be triggered by infection with viruses or bacteria, or certain toxins.
The symptoms include nausea, vomiting, diarrhoea and abdominal pain. In most cases, gastroenteritis clears up without the need for specific medical treatment.
Causes of gastroenteritis
Eating or drinking food that is contaminated by bacteria, viruses, or parasites allows them to enter the stomach and intestines (gastrointestinal tract). Some of these organisms can damage the cells lining the inner surface of the gut and interfere with the normal processes of the intestines. Certain bacteria or viruses may also produce toxins that irritate the gut and cause it to secrete excess amounts of fluid. This can lead to the various symptoms of gastroenteritis such as diarrhoea.
Viruses
Viruses are the major cause of gastroenteritis. Viruses that cause gastroenteritis include rotavirus, which is especially common in children, Norwalk virus and hepatitis A.
Viruses are spread from person to person, usually as a result of inadequate hand-washing after going to the toilet.
The time between catching the infection and the start of symptoms – the incubation period – is usually about a day. The most common symptoms are fever and vomiting which can last up to a week.
Bacteria
The commonest cause of bacterial gastroenteritis is food poisoning. Bacteria involved in food poisoning include Campylobacter (found in poultry), Salmonella (found in poultry and other meats and eggs), and Escherichia coli (E. coli – found in meats). All of these produce toxins as the bacteria multiply in the intestines after the food has been eaten. This means the symptoms may not begin until several hours after eating contaminated food.
Other common bacteria include Staphylococcus aureus and Bacillus cereus (which can contaminate rice, meat and vegetables). These secrete a toxin before the food is eaten. The bacteria multiply in prepared food and can cause symptoms soon after eating.
Some E.Coli strains, including E. Coli 157, produce 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. Other E.Coli strains are a major cause of traveller´s diarrhoea.
Parasites
Gastroenteritis can also be caused by parasites. Common parasites that cause infections include Giardia lamblia and Cryptosporidia, which live in some lakes and streams. They are spread by contaminated water, or from person to person. Giardia is often the cause of holiday gastroenteritis and can be effectively treated with antibiotics.
Other food problems
Some food allergies, for example an allergy to strawberries, can lead to gastroenteritis.
Symptoms of gastroenteritis
The incubation period depends on the cause. With viruses, the incubation period is usually about a day, with bacteria it ranges from a few hours to four days, and with parasites it can be up to 7–10 days.
Symptoms also vary depending on the cause. They may include any or all of the following:
- diarrhoea, which may contain blood and mucus, or be watery, greasy or frothy,
- nausea and vomiting,
- abdominal cramping, bloating or pain,
- fever,
- generally feeling unwell.
Most people recover within a week. However, with severe infections, the illness may persist for many weeks.
Sometimes, gastroenteritis can lead to chronic problems. For example, about 10% of cases of Salmonella infections lead to chronic bowel inflammation, resulting in continuing bloody diarrhoea. Occasionally, in the recovery phase people get pain in the large joints such as the knee. This settles down in time.
The symptoms of gastroenteritis may be confused with other bowel conditions, such as irritable bowel syndrome.
It´s important to seek medical advice if symptoms persist for more than a week, if there has been recent travel abroad or if the illness appears to have spread.
Catching gastroenteritis
The infection is transmitted in inadequately cooked food that is contaminated with bacteria. Over half of raw poultry may contain Salmonella bacteria, but proper cooking should kill this. Infection can also be passed on from one contaminated food to another during preparation. When food is left standing before it´s eaten, this gives bacteria a chance to multiply.
Some bacterial and viral Infections can also be spread from person to person. This happens after the infected person has defecated and not washed their hands properly afterwards, before handling food or touching other people. Others are only spread in food, especially in shellfish harvested in polluted waters.
In the developing world the majority of infections are carried in contaminated drinking water.
Treatment
Most cases of gastroenteritis can be treated at home.
Home treatment
The most important aspect of treatment is fluid replacement, to prevent dehydration. In mild cases of gastroenteritis, the usual daily drinks (water, tea, soup) should be enough.
In more severe infections, when lots of fluid has been lost through persistent diarrhoea and/or vomiting, dehydration is possible. The balance of salts in the body may also be disturbed. In these circumstances, it´s a good idea to use an oral re-hydration solution, sold by a pharmacist. These are usually a powder that is made up into solution by adding water. They contain the right balance of sugars and salts for the body and they encourage re-hydration.
Take small sips of drinks and bites of salty crackers until you feel well enough to eat again. When your appetite returns, eat mild foods such as rice, dry toast, or bananas.
Medicines
Medicines to stop diarrhoea are best reserved for short-term situations, such as making travel easier, or to get through a social event. These medications slow down the intestines, but have no effect on the excess fluid in the intestines. It will come out later. They can also have side-effects such as causing a dry mouth, and can temporarily make it hard to pass urine properly (urinary retention).
If pain is a problem, a simple pain reliever may be helpful.
When to contact a doctor
- pain does not respond to normal painkillers,
- vomiting or diarrhoea continues for more than a few days,
- there is blood or mucus in the diarrhoea,
- no fluids can be held down – this can lead to dehydration,
- there are signs of severe dehydration, including a dry mouth, reduced urine output, and, later, confusion.
A doctor may prescribe an anti-sickness medicine (anti-emetic). 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. In general therefore, doctors do not prescribe antibiotics for a typical case of gastroenteritis.
However, if a bacterial infection is suspected, the doctor may ask for a stool sample to send for laboratory testing. The results will help to determine which is the most appropriate antibiotic to use.
Hospital treatment
When fluid loss is severe enough to cause significant dehydration with low blood pressure and confusion, or when there is frequent vomiting, hospital treatment may be needed for intravenous fluid replacement.
Prevention
The best way to prevent gastroenteritis is to always wash hands after going to the toilet and to practice good food hygiene. For example, store fresh food in a fridge at 5°C. Keep raw meat away from food, such as salads, that are eaten raw. Cook food through thoroughly. Do not allow cooked food to stand around at room temperature - serve hot food, piping hot.
Gastroenteritis in children
Gastroenteritis is one of the most common childhood illnesses. Most infants and toddlers have at least one or two bouts of it a year.
In most cases, gastroenteritis is a mild illness caused by a viral infection and clears up without the need for medical treatment. In babies and young children, it can be more dangerous because they become dehydrated more easily.
What is gastroenteritis?
Gastroenteritis makes children sick (vomit) and gives them diarrhoea. These symptoms result from inflammation or irritation of the stomach and intestines - the gastrointestinal tract, or gut.
Gastroenteritis may be caused by bacteria or viruses in contaminated food or by being passed on from others.
Some of these germs can damage the cells that line 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 leads to the various symptoms of gastroenteritis, such as diarrhoea.
Viruses
Viruses are the main cause of gastroenteritis in children. The most common is the rotavirus group.
Viruses are spread from person to person, usually as a result of inadequate hand washing after going to the toilet.
The incubation period (the time between catching the infection and the start of symptoms) is usually about a day. The most common symtoms are fever and vomiting, which can last up to a week.
Bacteria
The most common cause of bacterial gastroenteritis is food poisoning. Bacteria involved in food poisoning include Campylobacter (found in poultry) Salmonella (found in poultry, other meats and eggs). These bacteria produce toxins as they multiply in the gut after the food has been eaten. This means that symptoms may not begin until several hours after eating contaminated food.
Other bacteria, Staphylococcus aureus, cause symptoms within a few hours of eating because the toxin is secreted into the food before it´s eaten.
Parasites
These rarely cause gastroenteritis. Parasites such as Giardia lamblia and Cryptosporidium are the common causes. If children have been living or holidaying in poorer countries, causes such as amoebiasis or worm infections should be considered.
Other causes
There are a number of other conditions that can cause vomiting or diarrhoea in children. Cow´s milk intolerance (in infants) or allergy to foods, such as milk or eggs, can cause nausea and vomiting. Any parent who is concerned that a child may be allergic or intolerant to any food should get advice from their health visitor or GP.
Rarely, a bladder (urinary tract) infection or illnesses such as encephalitis, appendicitis or diabetes can cause symptoms of gastroenteritis. Vomiting can also happen with migraines or when the gut is blocked. Malaria should also be considered if the child has recently returned from a high-risk country.
Symptoms
Symptoms vary depending on the cause. Viral gastroenteritis usually lasts for about two to four days and causes both diarrhoea and vomiting. In children with rotavirus infection, vomiting usually starts before the diarrhoea, and a high temperature is common in the first few days.
The main symptom of bacterial gastroenteritis is diarrhoea, which may have blood in it particularly with Salmonella and Shigella infection. Campylobacter infection is often associated with abdominal pain and a high temperature.
Dehydration
The main risk of gastroenteritis in children, particularly babies and young children, is that they become dehydrated. This can occur very quickly in babies because they do not need to lose a lot of fluid to lose a significant percentage of total body fluid. The symptoms of mild to moderate dehydration may include:
l lethargy or sleepiness
l loss of elasticity in the skin, so that when it is pinched between the fingers it does not immediately spring back into its normal position
l in young babies, the fontanelle (or soft spot on the scalp) may be sunken
l dry lips and mouth
l sunken eyes
l irritability
l thirst
l decreased or absent tears
l reduced output of urine (less wet nappies than usual)
With more severe dehydration there may also be:
l pale or mottled skin
l very low urine output (very few wet nappies)
l significant drowsiness
l fast heart rate
l cold fingers and toes - when squeezed, blood takes a long time to return to skin
When to see a doctor
Medical advice is needed if a child is becoming dehydrated, or if there is a possibility that the illness is not a simple gut infection. Parents often know best if a child seems unwell, for example they are not responding normally, or seem abnormally drowsy.
Any child with the following symptoms should also see a doctor:
l blood in the stools
l severe abdominal pain
l a high temperature - over 38°C or (101.3?F) for three days, or any high temperature in a child under three months.
Treatment
Most cases of gastroenteritis can be treated at home.
Home treatment
The most important part of treating children with gastroenteritis is replacing fluid lost through vomiting and diarrhoea and so keeping them hydrated.
Children who are not dehydrated only need to continue with their normal diet and fluid intake, but allowing for the losses from the vomiting and/or diarrhoea. "Little and often" is a good rule of thumb for them.
Even if children vomit the fluid back, some of what was drunk is likely to remain, so continue to offer fluids even if the child is vomiting. Look out for any symptoms of dehydration.
Children with mild to moderate dehydration can be treated with oral rehydration powders that are made up into solutions with water. These can be bought from a pharmacy. However, any fluid is better than none, so if the child refuses the solution, give them what they will drink.
Once rehydrated all children should continue normal feeding. Women who are breastfeeding should continue with this, and give oral rehydration on top if needed. Parents should not stop feeding milk to a baby unless diarrhoea continues for more than a few days, and only after getting advice from a doctor.
Medicines
Children should not be given medicines to stop diarrhoea (anti-diarrhoeals) or vomiting (antiemetics). They do not stop the excessive production of fluids that causes the diarrhoea, so it will collect in the gut and come out later. These medicines may also cause side-effects such as drowsiness and skin reactions.
Most children don´t need antibiotics, which are only useful to treat specific bacterial infections. They are normally only prescribed after a stool sample has been analysed in a laboratory and shown bacteria are there.
Hospital treatment
Children who become severely dehydrated need urgent hospital treatment and possibly intravenous (IV - into a vein) fluid replacement. This contains a balance of salts, (eg sodium and potassium), and glucose which helps fluids and salts to be absorbed in the gut. Most children recover with this simple treatment.
Usually normal feeding can begin again within 24 hours, although some children may need to have intravenous fluid replacement as long as the symptoms last.
Prevention
Most children will get gastroenteritis at some time no matter how high the standards of hygiene are at home. Some viral gastroenteritis infections can be spread by coughs and sneezes.
To help prevent gastroenteritis encourage children to always wash their hands before handling food and after going to the toilet.
If a child has gastroenteritis, help to prevent it spreading to other family members by:
- washing your hands thoroughly after changing their nappy
- hygienically disposing of, or properly cleaning, all soiled items such as nappies
- clean the toilets they use regularly, including wiping the flush handle and toilet seat with disinfectant
- not sharing towels and flannels
- not letting them help to prepare food for others