Diarrhea

Diarrhea, also known as the runs or the trots, is when someone has at least three loose or watery bowel movements in one day. It usually lasts a few days and can cause the body to lose fluids, leading to dehydration. Early signs of dehydration include skin that doesn’t bounce back quickly and irritability. If it gets worse, a person might urinate less, have pale skin, a fast heartbeat, or seem less responsive.

Most cases of diarrhea happen because of an infection in the intestines from a virus, bacterium, or parasite. These infections often come from eating contaminated food or drinking unsafe water, or from close contact with someone who is sick. Diarrhea can also be caused by things like lactose intolerance, certain medicines, or health conditions such as irritable bowel syndrome.

Diarrhea can be prevented by keeping things clean, such as improving sanitation, drinking clean water, and washing hands with soap. Giving babies breastfeeding for at least six months and vaccination against rotavirus also helps. The best treatment is an oral rehydration solution, which is clean water mixed with a little salt and sugar. Zinc tablets are also useful. In severe cases, medicines like intravenous fluids might be needed, but most people get better just by drinking fluids.

Every year, between 1.7 and 5 billion people get diarrhea. It’s most common in developing countries, where young children often get it three times a year. Diarrhea causes many child deaths each year, but numbers have improved since 1990. It can also lead to long-term problems like malnutrition, slow growth, and learning difficulties in children.

Terminology

The word diarrhea comes from Ancient Greek, meaning "flow through." In American English, we use the spelling diarrhea, while British English uses diarrhoea. Canadian English may use either spelling.

People sometimes use fun names for this condition, like "the runs," "the squirts," "Hershey squirts," "Montezuma’s Revenge," or "the trots."

Definition

Diarrhea happens when someone has three or more loose or watery stools in one day, or more than what is normal for them.

Acute diarrhea is when this happens for less than 14 days. It can be watery and is sometimes called AWD (Acute Watery Diarrhoea). There are different types of diarrhea, such as secretory, osmotic, exudative, inflammatory, and dysentery, each with its own causes and features.

Health effects

Diarrhea can affect both a child's body and mind. It can lead to poor nutrition, which makes it harder for children to grow strong and stay healthy. Even after treating other problems, children who have had severe diarrhea may do worse on thinking and learning tests.

Diarrhea can also cause the body to lose important fluids and minerals, which can make a child feel very tired. It might also make medicines less effective because they move through the body too quickly. Because of these effects, diarrhea can make daily life harder, especially for older people who might need extra care.

Causes

In the later stages of digestion, our bodies add water and fluids to help break down food. The large intestine usually takes this water back in to keep us hydrated. But sometimes, it can't take in all the water, and we end up with loose or watery stools — that's diarrhea.

Acute diarrhea often happens because of a virus, especially in young children. For people traveling in new places, bacteria can be the main cause. Some toxins from foods and certain medicines can also lead to sudden diarrhea. Long-term diarrhea can be linked to health problems affecting the intestines, like inflammatory bowel disease or conditions that make it hard to absorb nutrients properly.

Pathophysiology

Evolution

Some researchers think that diarrhea might be a natural way the body defends itself. If diarrhea is stopped too soon, it might take longer to get better. For example, a study from 1973 showed that people with a certain infection who used a medicine to stop diarrhea stayed sick for twice as long as those who did not use the medicine. These researchers suggest that letting the body have diarrhea could be part of healing.

Diagnostic approach

Sometimes, doctors need to do more tests to understand why someone has diarrhea. This is especially true for babies, young children with bad diarrhea, or if the diarrhea has blood in it, lasts more than two days, or comes with other symptoms like stomach pain, fever, or weight loss. Travelers and people who prepare food for others also might need extra checks, as they could spread the problem.

If diarrhea continues for over four weeks, doctors might suggest several tests. These can include checking blood for signs of anemia or thyroid problems, testing stool for certain germs or parasites, and in some cases, looking at the colon with a special camera. Some tests help find out if there are issues like lactose intolerance or problems with the intestines. Not all tests are needed for everyone—doctors decide based on what they think might be causing the problem.

Epidemiology

Diarrhea is a common health problem around the world. In 2004, there were about 2.5 billion cases of diarrhea, leading to 1.5 million deaths in children under five years old. Most of these cases and deaths happened in Africa and South Asia. Diarrhea is a major cause of death in young children, especially in places where healthcare and clean water are limited.

The World Health Organization has noted that deaths from diarrhea have decreased by 45% since 2000. Climate change can also affect the spread of diarrhea, as warmer temperatures and heavy rains can lead to more cases. Even animals, such as primates, can experience diarrhea, and some have special parts in their bodies that help protect against it.

Prevention

Further information: WASH § Health aspects

Improving drinking water and keeping things clean can help stop diarrhea. Using water filters, getting clean piped water, and having good sewer systems can all lower the chances of getting sick. Washing hands with soap, using toilets, and having proper sanitation also help keep diarrhea away.

Washing hands with soap and water can cut the risk of diarrhea by about one-third to almost half. In places with less money, not everyone has easy access to soap and water, making it harder to stay healthy. Teaching people good hygiene habits can make a big difference.

Clean water is very important. Providing clean water and good sanitation can greatly reduce how often people get sick. Treating water with chlorine can also help keep it safe.

Vaccines can help prevent some diseases that cause diarrhea. Vaccines for rotavirus have helped save lives, especially in places where this virus is common. New vaccines are being made to fight other causes of diarrhea, too.

Good nutrition matters. Giving zinc supplements has been shown to lower the chances of diarrhea. Vitamin A can also help, but giving both zinc and vitamin A works best. Breastfeeding helps protect babies from diarrhea. Babies who are breastfed only for the first six months are much safer from getting sick.

Using probiotics can help prevent diarrhea in people taking antibiotics. Spraying insecticides can also lower the risk of diarrhea in places where flies are a big problem.

Management

In most cases of diarrhea, the main treatment is to replace lost fluids and salts. This can usually be done by drinking special solutions, like oral rehydration therapy, or in serious cases, through special medical ways like intravenously. It's important for children with diarrhea to keep eating normally. Continuing to eat helps them recover faster and supports their growth.

Sometimes, medicines such as loperamide and bismuth subsalicylate can help, but they should only be used when a doctor says it's safe.

Fluids

Oral rehydration solution (ORS) is a special mix of slightly sweetened and salty water that helps prevent dehydration. Simple home solutions like salted rice water or soups with salt can also work. Commercial solutions like Pedialyte are available, and groups like UNICEF provide packets of salts and sugar for making ORS at home.

It's important to start giving fluids as soon as possible to prevent dehydration. If a child vomits, wait a few minutes and then give small amounts of the solution slowly. Drinks with a lot of sugar, like soft drinks, aren't recommended for young children because they can make dehydration worse. Plain water can be used if special ORS isn't available.

Eating

Children with diarrhea should keep eating normally. Stopping food can make diarrhea last longer. Breastfed babies should continue to breastfeed, and other children should eat their usual foods. Foods with certain fibers might help, but others could make things worse.

Medications

Main article: Antidiarrhoeal

Some medicines can help with diarrhea, but they should only be used in certain situations. Antibiotics are usually not needed unless a specific type of infection is causing the diarrhea. Some medicines can help reduce the number of bowel movements but might not shorten the illness. Natural substances like Diosmectite and other treatments can also help with symptoms.

Alternative therapies

Eating green bananas can help children with diarrhea recover faster. Taking zinc might help older children in areas where malnutrition is common. Some studies show that probiotics don’t greatly change how long diarrhea lasts, but they might help prevent diarrhea caused by antibiotics in adults. For children who can't digest lactose, special enzymes can help with symptoms when they drink dairy products.