What is diarrhea?
Diarrhea is having more than three bowel movements in a day where the stool is usually loose and watery. In South Africa, the UK English spelling is used – diarrhoea. It is also commonly known as a runny tummy or running stomach. Diarrhea is a symptom and not a disease. It is a very common symptom of many different types of bowel diseases and occurs several times in a person’s life. In most of these cases it lasts for a few days at most and can be overcome with little or no treatment. However, sometimes diarrhea can lead to such severe fluid and salt loss that it can be life threatening.
The Strict Definition of Diarrhea
Most of us think of even a single watery bowel movement as diarrhea. However, there are specific criteria for diarrhea.
- Diarrhea is the passing of more than 200 grams of solid stool or 200 millilitres of watery stool in a day.
- Diarrhea is having more than 3 bowel movements in a day.
Watery and loose stool is technically not diarrhea if it has not met the criteria above. However, in most cases of diarrhea the stool is not well formed and often watery.
Reasons for Diarrhea
In order to understand the different types of diarrhea, it is first important to know how normal stool is formed. The food that we eat is the basis for the stool that we pass out in a bowel movement. Food is digested, nutrients absorbed and the waste is expelled. This entire process is facilitated by the movement of food, and later wastes, through the gut by waves of motion in the gut wall (peristalsis).
In the small intestine, water is pumped into the gut to help with digestion. By the time digestion and absorption of nutrients has occurred, the remaining watery material reaches the large intestine (mainly made up of the colon). Here the water is reabsorbed into the body changing the liquid into a semi-solid mush and then a firmer solid stool.
This process of digestion, absorption and stool formation happens over anywhere between 12 to 72 hours. In diarrhea however, there is excessive water pumped into the gut, inadequate reabsorption of water from the waste or faster than normal movement of material in the gut (peristalsis). It may be a result of something that a person ate or drank, microbes like bacteria irritating the gut wall, anxiety and psychological stress or diseases of the gut wall.