Digestive health centre

Diarrhoea: Symptoms, treatment and prevention

What is diarrhoea?

Diarrhoea is a symptom of various illnesses and bowel disturbances during which someone passes more frequent, loose, watery stools.

Almost everyone has diarrhoea at some point in his or her life. In developing countries, where illnesses that cause diarrhoea are more common and where health care is less readily available, diarrhoea is a major health concern because of its potential to cause severe, life-threatening dehydration. Infants and the elderly are more prone to dehydration from diarrhoea.

Diarrhoea that comes on suddenly and lasts for no longer than a couple of days is usually referred to as "acute diarrhoea". Most people with acute diarrhoea recover on their own. Diarrhoea that lasts more than two weeks is thought of as "chronic diarrhoea". Typically, chronic diarrhoea requires medical care to find the underlying cause and treat complications, such as dehydration.

What causes diarrhoea?

Many different problems can cause diarrhoea. Here are the major causes:

You are most likely to come down with diarrhoea after coming into contact with these infectious organisms and agents:

• A virus, such as rotavirus, winter vomiting disease (Norwalk virus or norovirus), enterovirus, or a hepatitis virus.
• A bacterium, such as E. coli, salmonella, shigella, C.diff (clostridium), or cholera (Vibrio cholerae).
• A parasite, such as those that cause giardiasis and amoebiasis.

You may pick up an infectious agent from contact with another individual who has it, or you may get it after eating contaminated food or drinking contaminated water. If you eat food that was improperly cooked or was contaminated after cooking, you may get food poisoning, which can lead to diarrhoea. Children who attend nurseries and play groups and their families are more likely to be exposed to certain infectious agents.

Many people who travel to foreign countries develop what is termed "traveller's diarrhoea," usually after drinking contaminated water. Infectious diarrhoea is a particular hazard in developing countries where it may be difficult to keep waste water and sewage separate from water used for cooking, drinking, and bathing and where inadequate facilities make it difficult to practise good personal hygiene.

Other medical conditions

A number of non-infectious medical conditions may cause diarrhoea, too. These include:

• Inability to digest certain foods, including a lactose intolerance (difficulty digesting the type of sugar found in dairy products); coeliac disease (an intolerance of gluten in wheat and some other grains); and pancreatic problems, such as those caused by cystic fibrosis, which interfere with production of important digestive substances.
• Surgery to remove part of your intestine. A shortened intestine may be unable to absorb all the substances you eat. This is referred to as short-bowel syndrome.
• The after-effects of surgery to remove the gallbladder. An increase in bile in the colon may result in watery stools.
• Certain diseases of the endocrine (hormonal) system, including thyroid disease, diabetes, adrenal disease, and Zollinger-Ellison syndrome.
• Certain rare tumours (including carcinoid tumour and pheochromocytoma) that produce diarrhoea-causing substances.
• Inflammation in the intestinal tract, which can result in chronic diarrhoea. If you have inflammatory bowel disease (such as ulcerative colitis or Crohn's disease), you will have bouts of diarrhoea during flare-ups of your disease. 
• Pouches of the intestinal wall in diverticular disease can lead to diarrhoea, especially if they become infected and inflamed ( diverticulitis) 
• Irritable bowel syndrome, which may cause alternating bouts of diarrhoea and constipation.
• Bowel cancer produces a change in bowel habit that may include diarrhoea or alternating diarrhoea and constipation.