Diarrhoea is the passage of loose or watery stools, usually associated with the need to go to the toilet more than four times in a 24 hour period.
If diarrhoea is the result of a bacterial or viral infection, it tends pass after a few days. This is known as acute diarrhoea.
However, if you are suffering from diarrhoea because of condition such as Irritable Bowel Syndrome (IBS), then it is likely that your symptoms will persist and last much longer and this is often referred to as chronic diarrhoea.
Diarrhoea can affect a wide range of people, however, depending on the cause; different groups of people may be more susceptible to particular types.
Infection by a bug (viruses or bacteria) is a normal part of childhood. Your immune system is coming into contact with many of these pathogens for the first time and needs to build resistance. As you come into contact with more and more bugs, for example during your time in nursery, your immune system strengthens and prepares you for a lifetime of exposure.
This said; we can still succumb to infection at any age. Food-borne pathogens can be particularly aggressive and give rise to nasty bouts of food poisoning. Food poisoning often causes vomiting and acute diarrhoea. We are particularly vulnerable when travelling abroad to new countries so should be careful to avoid tap water and other likely sources of bacteria.
Acute diarrhoea is the sudden onset of diarrhoea that typically doesn’t last any longer than 14 days. Generally, acute diarrhoea is caused by bowel infection, also called gastroenteritis.
Gastroenteritis can be caused by viruses (common strains include norovirus or rotavirus), bacteria (helicobacter pylori, C. Difficile, E.coli, or salmonella, which often give rise to food poisoning), fungi (candida albicans) or in less common cases parasites.
Acute diarrhoea caused by infection may be accompanied by vomiting, symptoms of fever and dehydration.
Other causes of acute diarrhoea include: excessive consumption of certain food and drinks, short-term use of certain medications that can upset your bowels (e.g. antibiotics) or periods of extreme stress or anxiety. Read our blog post on how stress can impact the digestive system.
Chronic or persistent diarrhoea is often a sign your gut is irritated or worse, inflamed. Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder in which the role of the gut is disturbed. The cause of IBS is not well understood, although a variety of factors are thought to contribute. Uncoordinated bowel contractions are a common feature of IBS, often diarrhoea is a result of this.
Inflammatory Bowel Disease (IBD), as the name suggests, means the bowel is inflamed. Crohn’s disease and ulcerative colitis are examples of IBD and chronic diarrhoea is a common feature of these conditions too.
The presence and severity of chronic diarrhoea can fluctuate and can be influenced by factors such as diet or lifestyle. Therefore, over time, it may be possible to manage it relatively well, unlike acute diarrhoea which is harder to control.
Different mechanisms taking place in the gut can give rise to diarrhoea. These include:
- Uncoordinated contractions of gut muscles: This is commonly the cause of diarrhoea associated with IBS. The exact cause if this is unknown but it is thought to have a strong connection with the brain. The brain and gut are joined by a network of nerves which send signals to the muscles in the gut wall. This is why nervous states such as anxiety are thought to have a direct impact at the gut
- Secretory diarrhoea: Toxins release by harmful bacteria (cholera for example) can cause a shift in the movement of electrolytes in our cells, for example sodium, which triggers the movement of water with it. The presence of excess water moving into the bowel can cause diarrhoea. The osmotic balance of the gut can also be disturbed when we consume excessive amounts of sugar, salt, or other dietary elements such as fructose. These components can also draw excess water into the bowel, as your body attempts to dilute them
- Inflammation: The function of your gut is affected in the presence of inflammation. This means secretions may become abnormal as above but absorption is also likely to be affected. This makes diarrhoea worse and can result in malnutrition; as is often seen in disorders such as Crohn’s disease.