Diarrhea, also spelled diarrhoea, is the condition of having at least three loose or liquid bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are breastfed, however, may be normal.
The most common cause is an infection of the intestines due to either a virus, bacteria, or parasite; a condition known as gastroenteritis. These infections are often acquired from food or water that has been contaminated by stool, or directly from another person who is infected. It may be divided into three types: short duration watery diarrhea, short duration bloody diarrhea, and if it lasts for more than two weeks, persistent diarrhea. The short duration watery diarrhea may be due to an infection by cholera, although this is rare in the developed world. If blood is present it is also known as dysentery. A number of non-infectious causes may also result in diarrhea, including hyperthyroidism, lactose intolerance, inflammatory bowel disease, a number of medications, and irritable bowel syndrome. In most cases, stool cultures are not required to confirm the exact cause.
Prevention of infectious diarrhea is by improved sanitation, clean drinking water, and hand washing with soap. Breastfeeding for at least six months is also recommended as is vaccination against rotavirus. Oral rehydration solution (ORS), which is clean water with modest amounts of salts and sugar, is the treatment of choice. Zinc tablets are also recommended. These treatments have been estimated to have saved 50 million children in the past 25 years. When people have diarrhea it is recommended that they continue to eat healthy food and babies continue to be breastfed. If commercial ORS are not available, homemade solutions may be used. In those with severe dehydration, intravenous fluids may be required. Most cases; however, can be managed well with fluids by mouth. Antibiotics, while rarely used, may be recommended in a few cases such as those who have bloody diarrhea and a high fever, those with severe diarrhea following travelling, and those who grow specific bacteria or parasites in their stool. Loperamide may help decrease the number of bowel movements but is not recommended in those with severe disease.
About 1.7 to 5 billion cases of diarrhea occur per year. It is most common in developing countries, where young children get diarrhea on average three times a year. Total deaths from diarrhea are estimated at 1.26 million in 2013 – down from 2.58 million in 1990. In 2012, it was the second most common cause of deaths in children younger than five (0.76 million or 11%). Frequent episodes of diarrhea are also a common cause of malnutrition and the most common cause in those younger than five years of age. Other long term problems that can result include stunted growth and poor intellectual development.
A number of diseases and conditions can cause diarrhea, including
- Viruses. Viruses that can cause diarrhea include Norwalk virus, cytomegalovirus and viral hepatitis. Rotavirus is a common cause of acute childhood diarrhea.
- Bacteria and parasites. Contaminated food or water can transmit bacteria and parasites to your body. Parasites such as Giardia lamblia and cryptosporidium can cause diarrhea.
Common bacterial causes of diarrhea include campylobacter, salmonella, shigella and Escherichia coli. When traveling in developing countries, diarrhea caused by bacteria and parasites is often called traveler’s diarrhea. Clostridium difficile infection can occur, especially after a course of antibiotics.
- Medications. Many medications, such as antibiotics, can cause diarrhea. Antibiotics destroy both good and bad bacteria, which can disturb the natural balance of bacteria in your intestines. Other drugs that cause diarrhea are cancer drugs and antacids with magnesium.
- Lactose intolerance. Lactose is a sugar found in milk and other dairy products. People who have difficulty digesting lactose have diarrhea after eating dairy products.
Your body makes an enzyme that helps digest lactose, but for most people, the levels of this enzyme drop off rapidly after childhood. This causes an increased risk of lactose intolerance as you age.
- Fructose. Fructose, a sugar found naturally in fruits and honey and added as a sweetener to some beverages, can cause diarrhea in people who have trouble digesting it.
- Artificial sweeteners. Sorbitol and mannitol, artificial sweeteners found in chewing gum and other sugar-free products, can cause diarrhea in some otherwise healthy people.
- Surgery. Some people have diarrhea after undergoing abdominal surgery or gallbladder removal surgery.
- Other digestive disorders. Chronic diarrhea has a number of other causes, such as Crohn’s disease, ulcerative colitis, celiac disease, microscopic colitis and irritable bowel syndrome.
Signs and symptoms associated with diarrhea may include:
- Loose, watery stools
- Abdominal cramps
- Abdominal pain
- Blood in the stool
- Urgent need to have a bowel movement
Besides conducting a physical exam and reviewing your medications, your doctor might order tests to determine what’s causing your diarrhea. They include:
- Blood test. A complete blood count test can help determine what’s causing your diarrhea.
- Stool test. Your doctor might recommend a stool test to determine whether a bacterium or parasite is causing your diarrhea.
- Flexible sigmoidoscopy or colonoscopy. Your doctor might recommend one of these procedures to look at the lining of your colon and provide biopsies if no cause is evident for persistent diarrhea.
Both procedures involve using a thin, lighted tube with a lens on the end to look inside your colon.
Most cases of diarrhea clear on their own within a couple of days without treatment. If you’ve tried lifestyle changes and home remedies for diarrhea without success, your doctor might recommend medications or other treatments.
Antibiotics might help treat diarrhea caused by bacteria or parasites. If a virus is causing your diarrhea, antibiotics won’t help.
Treatment to replace fluids
Your doctor likely will advise you to replace the fluids and salts. For most adults, that means drinking water, juice or broth. If drinking liquids upsets your stomach or causes diarrhea, your doctor might recommend getting fluids through a vein in your arm (intravenously).
Water is a good way to replace fluids, but it doesn’t contain the salts and electrolytes — minerals such as sodium and potassium — you need to maintain the electric currents that keep your heart beating. You can help maintain your electrolyte levels by drinking fruit juices for potassium or eating soups for sodium. Certain fruit juices, such as apple juice, might make diarrhea worse.
For children, ask your doctor about using an oral rehydration solution, such as Pedialyte, to prevent dehydration or replace lost fluids.
Adjusting medications you’re taking
If your doctor determines that an antibiotic caused your diarrhea, your doctor might lower your dose or switch to another medication.
Treating underlying conditions
If your diarrhea is caused by a more serious condition, such as inflammatory bowel disease, your doctor will work to control that condition. You might be referred to a specialist, such as a gastroenterologist, who can help devise a treatment plan for you.
In developing countries, prevention of diarrhea may be more challenging due to dirty water and poor sanitation. The following practical measures help to prevent the condition:
- Clean/safe drinking water
- Good sanitation (toilets and sewerage, for example)
- Handwashing with soap – after defecation, after cleaning a child who has defecated, after disposing of a child’s stool, before preparing food, and before eating
- For mothers with young babies, breastfeeding for the first 6 months of life
- Good hygiene practices – both personal hygiene and in the kitchen
- Education on the spread of infection
There is evidence that interventions from public health bodies to simply promote hand washing can cut diarrhea rates by about one-third.
Many home remedies have been suggested for the treatment of diarrhea; however, few of them have been well-studied. Three that have been studied and appear to be effective are:
- cooked green bananas, and
In over 90% of cases, acute diarrhea is mild, self-limited, and responds within 5 days to rehydration therapy or antidiarrheal agents. Individuals with diarrhea caused by infectious agents recover with appropriate antibiotic therapy. Diarrhea resulting from other causes improves with treatment of the underlying condition. Individuals with diarrhea of probable immune cause may have chronic inflammation with bouts of diarrhea for years.
Most deaths from diarrhea occur in the elderly whose health may be put at risk from a moderate amount of dehydration.
Dehydration occurs when there is excessive loss of fluids and minerals (electrolytes) from the body due to diarrhea, with or without vomiting.
- Dehydration is common among adult patients with acute diarrhea who have large amounts of watery stool, particularly when the intake of fluids is limited by lethargy or is associated with nausea and vomiting.
- It also is common in infants and young children who develop viral gastroenteritis or bacterial infection.
- Patients with mild dehydration may experience only thirst and dry mouth.
- Moderate to severe dehydration may cause orthostatic hypotension with (fainting or light-headedness upon standing) due to a reduced volume of blood, which causes a drop in blood pressure upon standing). A diminished urine output, severe weakness, shock, kidney failure, confusion, acidosis (too much acid in the blood), and coma also may occur.
Electrolytes (minerals) are lost with water when diarrhea is prolonged or severe, and mineral or electrolyte deficiencies may occur. The most common deficiencies occur with sodium and potassium. Abnormalities of chloride and bicarbonate also may develop.
Finally, there may be irritation of the anus due to the frequent passage of watery stool containing irritating substances.