Diarrhoea is the frequent passing of watery faeces (poo, also known as stools). Usually , food nutrients are absorbed in a part of the gut known as the small intestine, then the waste is pushed into the large intestine (bowel) where water is removed. The resulting faeces is stored temporarily within the rectum then passed out of the body through the anus. Faeces is usually firm, moist and easy to pass. When this process does not work properly, it results in diarrhoea.
The symptoms of diarrhoea
- Abdominal cramps
- Abdominal pains, sometimes eased after passing stools
- An urgent need to go to the toilet
- Frequent passing of loose, watery faeces
- Nausea and vomiting.
Causes of acute (short-term) diarrhoea
A bout of diarrhoea can be caused by a wide range of disorders, infections and events including food poisoning, gastroenteritis (stomach infection), tropical diseases such as typhoid and cholera, anxiety or emotional stress, excessive alcohol intake and medications (particularly antibiotics).
Contaminated food and water are very common causes of acute diarrhoea and infectious agents known to cause this include viruses such as calici virus, adenovirus and rotavirus; bacteria such as E. coli, Campylobacter, V. cholerae, Shigella, Salmonella and Staphylococcus aureus and parasites such as Giardia lamblia, Cryptosporidium parvum and tapeworm. In most cases, acute diarrhoea is self-limiting and will get better within a day or two.
Causes of chronic diarrhoea
- There are many possible causes of chronic diarrhoea including;
- Coeliac disease – which reduces the intestine’s ability to absorb food
- Chronic constipation – the bowel is blocked by hard, impacted faeces, but some liquids manage to seep past the blockage. This condition, called ‘spurious’ or ‘overflow’ diarrhoea, is more common in the elderly
- Hormone disorders – such as diabetes or hyperthyroidism (overactive thyroid gland)
- Cancer – such as bowel cancer
- Inflammatory bowel disease – including ulcerative colitis and Crohn’s disease
- Irritable bowel syndrome (IBS) – symptoms include abdominal pain, bloating, and alternating constipation and diarrhoea
- Lactose intolerance – the inability to digest the milk sugar lactose
- Medications – including antibiotics, antacids that contain magnesium, laxatives, and drugs for treating hypertension (high blood pressure) and arthritis.
If you have acute diarrhoea, the symptoms are likely to settle down within a week and tests are usually unnecessary. However, if your diarrhoea becomes more persistent or if you have other symptoms (such as blood in your stools or dehydration) your doctor may ask for a stool sample to investigate for bacteria or parasites. Other tests for chronic diarrhoea may include blood tests or a sigmoidoscopy (a procedure that involves passing a thin fibre-optic tube, attached to a viewing lens, through the rectum in the bottom to view the intestine).
Treatment for diarrhoea
This depends on the cause but often includes drinking plenty of fluids to prevent dehydration or using oral rehydration drinks to replace lost salts and minerals. These drinks are available from pharmacies but an alternative is one part unsweetened pure fruit juice diluted with four parts of water. Occasionally anti-diarrhoeal medications are required, but only on the advice of your doctor. If your diarrhoea is caused by infection, anti-diarrhoeal drugs may keep the infection inside your body for longer.
Always see your doctor if you experience serious symptoms. Babies and young children with diarrhoea need prompt medical attention.
Reducing the risk of spreading infection
Most cases of acute diarrhoea are potentially infectious to others. Viruses are easily spread, mainly through direct contact with vomit or faeces from an infected person or through contact with a contaminated object or surface. Occasionally, the virus may be transmitted by airborne particles generated from vomiting and diarrhoea.
You can reduce your chances of getting infected by carefully washing your hands after going to the toilet and before handling food. People looking after a person with the virus must also wash their hands thoroughly. Anyone with acute diarrhoea should stay at home if possible to reduce the spread of infection and it is recommended not to visit hospitals and nursing homes, and not to swim in public pools.
It may help to make a few short-term dietary adjustments while your bowels recover from acute diarrhoea. General suggestions include limiting your consumption of fatty, sweet or spicy foods, avoiding alcohol, increasing your consumption of starchy foods like banana, rice and bread and yoghurts containing live cultures. Diarrhoea in babies and young children can be made worse by fruit juice, so limit these drinks.
Causes for concern
- Contact your doctor immediately if you experience serious symptoms such as;
- Blood or pus in the faeces
- Painful passage of faeces
- Repeated vomiting
- An inability to increase fluid intake
- Reduced or absent urination
- Fever (temperature greater than 38ºC).
If you have a serious chronic medical condition, such as kidney or heart failure, even one day of diarrhoea can be dangerous. It’s safer to see your doctor as soon as possible. Diarrhoea can also be dangerous for babies and young children because their smaller bodies are more vulnerable to dehydration.