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Diarrhea

life science Maturity 11-13 Next article →

Diarrhea is a medical condition defined by having three or more loose, liquid, or watery bowel movements in a single day.

BristolStoolChart
BristolStoolChart

It can be a temporary issue or a persistent one lasting longer than two weeks. This condition is significant because it often leads to dehydration, which is a dangerous loss of body fluids. Dehydration can cause the skin to lose its normal stretchiness and lead to irritable behavior. As it becomes more severe, it may cause decreased urination, loss of skin color, a fast heart rate, and decreased responsiveness.

Stomach colon rectum diagram-en
Stomach colon rectum diagram-en

To understand how diarrhea works, we must look at the human gastrointestinal tract.

Stomach colon rectum diagram-en
Stomach colon rectum diagram-en

During digestion, food is broken down by gastric acid, bile, and enzymes. These nutrients are absorbed in the small intestine. Before waste leaves the body, the large intestine reabsorbs water and digestive solvents to maintain hydration and equilibrium. Diarrhea occurs when the large intestine is prevented from absorbing enough water from the fecal matter. This failure to absorb fluid results in the characteristic loose or liquid stools.

Scientists categorize diarrhea into several distinct types based on the underlying mechanism. Secretory diarrhea occurs when there is an increase in active secretion or a decrease in absorption. For example, the cholera toxin stimulates the secretion of chloride ions, which causes sodium and water to follow. Osmotic diarrhea happens when too much water is drawn into the bowels. This can be caused by consuming excessive sugar or salt, or by conditions like lactose intolerance where undigested nutrients pull water into the lumen.

BristolStoolChart
BristolStoolChart

Other types include exudative and inflammatory diarrhea. Exudative diarrhea involves the presence of blood and pus in the stool, often seen in severe infections or inflammatory bowel diseases. Inflammatory diarrhea occurs when the mucosal lining or brush border of the intestine is damaged. This damage leads to a passive loss of protein-rich fluids and reduces the body's ability to absorb them. If blood is visible in the stool, the condition is specifically known as dysentery. Dysentery can be caused by various organisms, such as Salmonella or Shigella.

Infections, often called gastroenteritis, are the most common cause of diarrhea. These can be caused by viruses, bacteria, or parasites. In children under five, rotavirus is a major cause, accounting for 40% of cases. For adults, norovirus is the most common viral cause. Bacterial infections like E. coli or Campylobacter are also frequent. In the elderly, the bacterium Clostridioides difficile can cause severe issues, especially after antibiotic use. Parasites like Giardia or Cryptosporidium can also lead to chronic infections.

Slum and dirty river
Slum and dirty river

Diarrhea has a massive global impact, with an estimated 1.7 to 5 billion cases occurring every year. It is most common in developing countries, where young children may experience it three times per year on average. In 2012, it was the second most common cause of death for children under five. While total deaths were estimated at 1.53 million in 2019, this is a decrease from 2.9 million in 1990. Frequent episodes can lead to malnutrition, stunted growth, and poor intellectual development in children.

Fortunately, many effective treatments and prevention methods exist. The preferred treatment is oral rehydration solution (ORS), which is clean water mixed with modest amounts of salts and sugar.

Cholera rehydration nurses
Cholera rehydration nurses

Zinc tablets are also a recommended treatment. These interventions have saved an estimated 50 million children over the last 25 years. Prevention relies on improved sanitation, clean drinking water, and regular hand washing with soap. Vaccination against rotavirus and breastfeeding for at least six months are also vital protective measures.

Cholera rehydration nurses
Cholera rehydration nurses
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En.Wikipedia-VideoWiki-Diarrhea.webm
File:BristolStoolChart.png
BristolStoolChart.png
File:Stomach colon rectum diagram-en.svg
Stomach colon rectum diagram-en.svg
File:Slum and dirty river.jpg
Slum and dirty river.jpg
File:Diarrhoeal diseases world map-Deaths per million persons-WHO2012.svg
Diarrhoeal diseases world map-Deaths per...
File:Diarrhoeal diseases world map - DALY - WHO2004.svg
Diarrhoeal diseases world map - DALY - WHO2004.svg
File:Cholera rehydration nurses.jpg
Cholera rehydration nurses.jpg
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