Diarrhoea is a common condition in which the person frequently passes loose or watery stools. World Health Organization (WHO) estimates that about 3.5 million deaths occur each year because of diarrhoea. Most of these deaths (about 80%) occur in children under the age of 5 years. Death and complication due to diarrhoea are common in children as a smaller amount of fluid loss in them leads to dehydration, compared to adults.
Types of diarrhoea: Based on duration diarrhoea can be categorized as acute or chronic diarrhoea.
Acute diarrhoea: When an episode of diarrhoea lasts less than 14 days, it is known as acute diarrhoea. Acute watery diarrhoea can cause dehydration (loss of electrolyte and water) and contribute to malnutrition. Acute diarrhoea is the leading cause of death in children in developing countries.
Death in acute diarrhoea is most often caused due to dehydration. Most cases of acute diarrhoea are caused due to infection with virus or bacteria or food poisoning. Acute diarrhoea in most cases is a self limiting illness which improves within a few days. Symptoms of diarrhoea usually subside in five to seven days in children and rarely last for more than two to four days in adults.
The time for which diarrhoea usually lasts varies depending on the type of infection. It may be as follows:
Chronic diarrhoea: If the diarrhoea lasts 14 days or more, it is known as chronic or persistent diarrhoea. An acute episode of diarrhoea may become chronic in about 20% of cases. Persistent diarrhoea increases the risk of malnutrition and may cause dehydration. Chronic diarrhoea may be caused by infection or it may be a symptom of some other disorder. Time period for which chronic diarrhoea may last depends on the underlying cause. Some common causes of chronic diarrhoea include:
Diarrhoea due to giardiasis (infection with the Giardia intestinalis parasite) may last several weeks. If persistent diarrhoea is caused because of irritable bowel syndrome, the person may have repeated episodes of diarrhoea. In cases with lactose intolerance or allergy to gluten (wheat protein), diarrhoea may start when the person is exposed to allergen.