Diarrhoea

This information explains what diarrhoea disorders are, when it is a problem you need to tell your doctor about, and what treatment is available.

Many healthy people open their bowels between three times a day and three times a week. The most common frequency is once or twice a day.

Normal poo is usually solid. This is because the small and large bowel are good at taking in (absorbing) nutrients and fluids. Diarrhoea can occur when one or more of these processes become faulty. Examples include:

• When digestion and absorption of food or fluid is impaired.
• When there is inflammation. For example, inflammation by some infections that
  damage the gut lining and lead to an oozing of fluid from the lining.
• When there is excessive fluid secretion due to infection, damage from drugs or
  abnormal amounts of some hormones.

Sometimes more than one occur. More liquid overwhelms the gut’s ability to reabsorb the fluid and salts. The poo becomes loose and watery. Bowel movements happen more often. In acute diarrhoea, symptoms come on quickly and last a short time.

Acute diarrhoea symptoms usually clear up within 5 to 7 days. Diarrhoea that is chronic lasts a longer time. It generally lasts 4 weeks or more.

You should always see your GP if the diarrhoea lasts a long time. They will investigate the cause.

There are many reasons why diarrhoea can occur. Common causes include:

Diverticular disease

This is where pouches form in the large bowel and can cause a change in bowel habit, commonly diarrhoea.

Food intolerance

The most common food intolerance is to lactose. 8 in 100 people might have lactose intolerance in the UK. It is caused by a reduction in levels of an enzyme called lactase which is produced in the small bowel. Lactase helps digest lactose, the sugar found in milk. Lactose intolerance sometimes happens because of lower levels of lactase from birth. It can also occur due to other digestive diseases. There are other intolerances such as gluten intolerance also known as coeliac disease.

Many companies sell intolerance tests. They claim to help people find food intolerances. Some examples of these tests include the IgG blood test. Also, kinesiology, hair analysis, or the pulse test also claim to test food intolerances. You should avoid these tests as they have no solid scientific basis.

They are not recommended to diagnose food intolerance by the NHS. The best way to diagnose a food intolerance is by monitoring symptoms when you eat certain foods. A dietitian should oversee this approach. This is so that the process avoids a very restricted diet.

Anxiety

Anxiety and stress can speed up bowel movements. This can cause diarrhoea.

Irritable bowel syndrome (IBS)

Approximately 1 in 3 people with IBS have diarrhoea with pain. IBS is a disorder of gut-brain interaction and causes pain. In people with IBS and diarrhoea (IBS-D) the bowel contents pull fluid from the body as they pass through. This means there is too much fluid in the poo to be absorbed. About 1 in 5 people with IBS-D symptoms may have bile acid diarrhoea.

About 1 in 10 people with IBS-D symptoms may have microscopic colitis (see below). In most cases, a
gastroenterologist can tell IBS from bile-acid malabsorption and microscopic colitis. They do this by taking a thorough clinical history. Tests may be arranged to look for bile acid diarrhoea and microscopic colitis.

Medicines 

Diarrhoea can occur during or after a course of antibiotics. Other medicines may also cause diarrhoea. Medicines can cause the bowels to move too fast. This results in too little time for absorption.

Some laxatives can cause too much fluid in the bowel. Ask your doctor if your medicine can cause diarrhoea. Do not stop taking any medicine your doctor has recommended. Talk to your doctor first.

Food poisoning

This is another type of bowel infection. Contaminated food or water causes food poisoning. The contamination is by bacteria. Common types are Salmonella or Campylobacter. Some foods that might include the bacteria are poultry and eggs.

A carrier is someone who has the infection but no symptoms. They can also spread the infection. Food poisoning can last about 3 to 7 days without treatment.

Bowel infection (gastroenteritis)

This is the most common cause of acute diarrhoea. Infants and young children are particularly susceptible. Norovirus diarrhoea often makes the news. It can occur in local epidemics. Diarrhoea caused by a virus can last anywhere from 2 to 3 days.

Functional diarrhoea

This is a disorder of gut-brain interaction. It is like IBS. But the diarrhoea occurs without major belly, or abdominal pain.

Bile acid diarrhoea (BAD)

This is a disturbance of the cycle of bile acid distribution in the body. Bile acid, made in the liver, is released into the small bowel to help break down fats in food. The problem occurs when it does not get taken back into the body at the end of the small bowel. The bile then causes watery diarrhoea when it reaches the large bowel. The most common cause is gallbladder surgery (cholecystectomy).

Coeliac disease 

This is an autoimmune condition. When gluten is eaten it harms the lining of the small bowel. This results in food passing through the body and not being used.

In some people this can result in diarrhoea. Gluten is protein that is found in wheat, barley and rye. It is found in bread, pasta, and wheat-based cereals. The doctor may do a blood test to check for coeliac disease. It is very important that you do not stop eating sources of gluten before the test. This is because the blood needs gluten antibodies for a diagnosis.

Inflammatory bowel disease

These are a range of autoimmune diseases. In them, the body attacks its own tissues. In people with Crohn’s disease inflammation can affect any part of the digestive tract. The digestive system goes from the mouth to the anus. People with ulcerative colitis have inflammation. The inflammation only affects the large bowel.

Microscopic colitis

This is an inflammatory disease of the bowel, which is not visible by looking at the bowel wall with a camera (colonoscopy). It is characterised by watery diarrhoea, usually accompanied by urgency and problems with bowel control.

Pancreatic exocrine insufficiency (PEI)

The pancreas has two functions. One of these is to produce digestive enzymes to help digest the food we eat (the other is to make hormones like insulin to regulate glucose). Pancreas problems can reduce its ability to make them. This can result in poor absorption. The poo
might be greasy and difficult to flush.

Bowel cancer

Diarrhoea can be a symptom of bowel cancer in some people. Particularly those people who have risk factors. Bowel cancer is more common in the following people:

• Those above the age of 50
• Cigarette smokers
• People who have a higher than healthy body weight
• People with a have a family history of bowel cancer

The health service has a programme to screen for bowel cancer. To be eligible to receive the test there are certain standards to meet. They are different across the four countries of the UK. People who are eligible will get a bowel cancer testing kit in the post every 2 years.

Pelvic radiation disease

Radiation treatment can harm the digestive tract during cancer treatment. This is a cause of diarrhoea in some people. The cancers where this can happen are of the lower belly and pelvis.

Surgery

Removal of large parts of the digestive tract can result in diarrhoea. Ask your surgeon for further advice.

Dumping syndrome

This can happen after surgery to the stomach. The cause is when the stomach releases food too quickly into the small bowel. The food is ‘dumped’ into the small bowel. This causes excess fluid in the small bowel. It also alters hormone levels. Both result in diarrhoea.

Other medical conditions can cause diarrhoea. But, they are much rarer. Rare means between 1 in 10,000 people to 1 in 1000 people.

Most acute diarrhoea symptoms get better, they don’t need specific medical advice. But, if your job is handling food, you should contact your doctor and you should also tell your employer. But, if the episode is severe there are several treatments that can help.

Some more vulnerable groups may need to seek advice sooner as there is a greater risk of dehydration. Babies, young children and older people are vulnerable.

Dehydration can cause dark coloured urine to occur. The doctor will want to talk to you about your symptoms to try to identify a cause. The doctor will also want to examine your belly. They might also check your back passage. The priority is to ensure that your poo is tested. This is to see if there are any bugs in it that could cause infection and diarrhoea.

It might be challenging to collect a sample if your diarrhoea is severe. See the NHS website for advice about how to collect a sample of poo.

Faecal calprotectin test: This is a poo test available to some GPs that shows inflammation in the digestive tract. It is used as part of the assessment for inflammatory bowel disease.

Faecal elastase test: This test can diagnose pancreatic exocrine insufficiency. This is when the pancreas doesn’t produce digestive enzymes to help digest food.

Blood test: The doctor may also do other blood tests. They are to rule out other causes, like coeliac disease. Some people with bowel cancer may have low blood iron levels. This is called anaemia. Your GP can test your blood for anaemia. Simple blood tests can also check for infection or IBD.

Diarrhoea is loose poo and the frequency of opening the bowel may be more than 3 times a day. Diarrhoea may cause cramping pain. The pain is in the centre or lower belly. Often people might have urgency to empty their bowel too.

See the Bristol Stool chart below. Diarrhoea is type 6 and 7.

Blood in poo can be a symptom of ulcerative colitis, a type of IBD, or bowel cancer. Seek medical advice from NHS 111 if any of these apply:

• If diarrhoea lasts for more than 7 days
• If you notice blood in the diarrhoea
• If you develop a fever
• If your temperature is 38°C (100.4°F) or above
• Or you are feeling hot, cold, or shivery
• If your cramping and belly pains become very bad
  and constant
• If you or a child is still dehydrated after using
  rehydration sachets, see the treatments section

You might also want to check Guts UK ‘Poo-Torial’ tool for more information.

Most cases of acute diarrhoea will clear up in a few days. They will do so without medical treatment. But, if the episode is severe there are several treatments that can help.

Rehydration: Ensure you have extra fluids and foods with table salts. You need them to replace those lost in the diarrhoea. Some groups are more sensitive to fluid loss. Examples include:

• Babies
• Young children
• Older people

For these groups it is a good idea to use a pre-prepared oral rehydration solution. You can buy it over the counter in most pharmacies. For many adults, you can treat dehydration by drinking more fluid. Suitable choices include:

• Water
• Salty soups (which also contain sodium another type of salt)

Have the fluids with starchy carbohydrates like rice, pasta, or crackers. This can help the fluid and salt absorb into the body.

Food intake: There is no need to stop eating. Although people often prefer a lighter diet in the early stage of the illness.

Breast-fed infants don’t need to stop breast-feeding. Give bottle fed infants full strength formula.  It might help some adults to avoid dairy, alcohol, and spicy foods. They should do this during the early stages of diarrhoea. Adults should begin eating their usual diet once it is tolerated. Report any long term problems with dairy products to your doctor.

Medicine: Anti-diarrhoea medicine is available from pharmacies. An example is loperamide. It helps to reduce the frequency of bowel opening.

Do not take this for acute diarrhoea if you suspect you have an infection or food poisoning as your body needs to expel the bugs. It may be useful for specific purposes (e.g. travelling home if you have food poisoning away from home). Loperamide can be very helpful if you have chronic diarrhoea that your doctor has diagnosed. It can enable you to travel, go to places where there is no toilet or eat out without worrying.

Do not give loperamide to children under 12 children. This is because of concerns that it may slow down breathing.

Contact your GP if you need to take this medicine for more than 48 hours. Do not take this medicine if you have blood in your poo or a temperature
(see symptoms section). Also do not use loperamide if you have a flare up of IBD. Contact your GP about these symptoms.

You can find more information here on the NHS website.

Can acute diarrhoea be avoided? 

One of the most important ways to avoid acute diarrhoea is by handwashing. This is especially true when travelling to hot countries or places with poor sanitation. Always wash your hands after using the toilet and before eating.

Many cases of acute diarrhoea are related to a bowel infection. This is usually caused by contaminated food or water. It is possible to avoid an illness by being very careful about food and fluid intake. This might be advice to follow when traveling. When water is impure, it may be safer to drink bottled or boiled water. People should also avoid ice cubes when the cleanliness of water is not clear. Also avoid the following:

• Raw, unpeeled fruits and salads
• Shellfish
• Foods that might contain raw egg

The safest foods are those which are piping hot and well-cooked. Fruit that you peel yourself can also be eaten.

Norovirus causes diarrhoea. It occurs in sudden local outbreaks. It is important not to spread the infection. So, during that time avoid visiting:

• Hospitals
• Older people’s homes
• Schools
• Unwell relatives

The earlier tips on hygiene should come first. They can protect against acute diarrhoea. But other treatments may help too. They can cut the chances of getting acute diarrhoea.

Antibiotics: A doctor may prescribe antibiotics. This happens when the acute diarrhoea is caused by bacteria if it is diagnosed in the lab quickly enough. Antibiotic overuse leads to resistance. So, only take antibiotics with medical advice. Antibiotics may also cause diarrhoea. It is a side-effect. This should usually get better once the course ends. Discuss this with a doctor or your GP if you are concerned.

Travellers with bad diarrhoea can find their holiday spoiled. But usually, symptoms last only 1 or 2 days. Travellers who are unwell should seek the help of a medical doctor. The doctor may give you antibiotics. This depends on your health and circumstances.

Vaccines: There are new vaccines for traveller’s diarrhoea. The United Kingdom has one effective vaccine. It’s called Dukoral. It’s use prevents one type of bacteria that causes the illness cholera. It helps approximately 8 people in 10. If you are travelling to risky areas, your doctor can offer it to adults and children over 2.

What about chronic diarrhoea?

Treatment of chronic diarrhoea varies. It will depend on the cause of the diarrhoea.

Does diarrhoea need to be monitored?

Many cases of acute diarrhoea will settle on their own. People who have chronic diarrhoea should seek help from their GP. Doctors should base the number and type of tests on a person’s history and exam. Some people may need a blood test. They may also need a poo sample test. Others may need an endoscopy, a camera test. An endoscope allows a doctor to see if there are any problems with the large bowel and samples (biopsies) of the bowel can be taken at the same time.

What to ask your doctor?

• Could my diarrhoea be caused by any medicines I am currently taking. If so, is there an alternative?
• Are there any over the counter treatments I can take?
• Do I need my poo checked?
• Do I need any more tests if diarrhoea lasts more than 7 days?

Other resources

The What’s Up With My Gut website makes the process of diagnosis easier to understand and less overwhelming, with step-by-step guides to support you to understand the actions your GP might take. This can help you to get the best out of your GP appointments and understand which conditions your GP might look into and what tests or investigations they might consider.