Diarrhoea is loose, watery stools occurring more than three times in one day. Diarrhoea is a common problem that usually lasts a day or two and goes away on its own without any special treatment. However, prolonged diarrhoea can be a sign of other problems. People with diarrhoea may pass more than a quart of stool a day.
Diarrhoea can cause dehydration, which means the body lacks enough fluid to function properly. Dehydration is particularly dangerous in children and the elderly, and it must be treated promptly to avoid serious health problems.
People of all ages can get diarrhoea. The average adult has a bout of diarrhoea about four times a year.
What causes diarrhoea?
Diarrhoea may be caused by a temporary problem, like an infection, or a chronic problem, like an intestinal disease. A few of the more common causes of diarrhoea are
Bacterial infections. Several types of bacteria, consumed through contaminated food or water, can cause diarrhoea. Common culprits include Campylobacter, Salmonella, Shigella, and Escherichia coli.
Viral infections. Many viruses cause diarrhoea, including rotavirus, Norwalk virus, cytomegalovirus, herpes simplex virus, and viral hepatitis.
Food intolerances. Some people are unable to digest some component of food, such as lactose, the sugar found in milk.
Parasites. Parasites can enter the body through food or water and settle in the digestive system. Parasites that cause diarrhoea include Giardia lamblia, Entamoeba histolytica, and Cryptosporidium.
Reaction to medicines, such as antibiotics, blood pressure medications, and antacids containing magnesium.
Intestinal diseases, like inflammatory bowel disease or coeliac disease.
Functional bowel disorders, such as irritable bowel syndrome, in which the intestines do not work normally.
Some people develop diarrhoea after stomach surgery or removal of the gallbladder. The reason may be a change in how quickly food moves through the digestive system after stomach surgery or an increase in bile in the colon that can occur after gallbladder surgery.
In many cases, the cause of diarrhoea cannot be found. As long as diarrhoea goes away on its own, an extensive search for the cause is not usually necessary.
People who visit foreign countries are at risk for traveller's diarrhoea, which is caused by eating food or drinking water contaminated with bacteria, viruses, or, sometimes, parasites. Traveller's diarrhoea is a particular problem for people visiting developing countries. Visitors to the United States, Canada, most European countries, Japan, Australia, and New Zealand do not face much risk for traveller's diarrhoea. (See "Preventing Traveller's Diarrhoea" below)
What are the symptoms?
Diarrhoea may be accompanied by cramping abdominal pain, bloating, nausea, or an urgent need to use the bathroom. Depending on the cause, a person may have a fever or bloody stools.
Diarrhoea can be either acute (short-term) or chronic (long-term). The acute form, which lasts less than 4 weeks, is usually related to a bacterial, viral, or parasitic infection. Chronic diarrhoea lasts more than 4 weeks and is usually related to functional disorders like irritable bowel syndrome or inflammatory bowel diseases like coeliac disease.
Diarrhoea in Children
Children can have acute or chronic forms of diarrhoea. Causes include bacteria, viruses, parasites, medications, functional disorders, and food sensitivities. Infection with the rotavirus is the most common cause of acute childhood diarrhoea. Rotavirus diarrhoea usually resolves in 3 to 9 days.
Medications to treat diarrhoea in adults can be dangerous to children and should be given only under a doctor's guidance.
Diarrhoea can be dangerous in newborns and infants. In small children, severe diarrhoea lasting just a day or two can lead to dehydration. Because a child can die from dehydration within a few days, the main treatment for diarrhoea in children is rehydration. (See "Preventing Dehydration" below .)
Take your child to the doctor if any of the following symptoms appear:
stools containing blood or pus, or black stools
temperature above 101.4 degrees Fahrenheit
no improvement after 24 hours
signs of dehydration (see below)
What is dehydration?
General signs of dehydration include
less frequent urination
dark colored urine
Signs of dehydration in children include
dry mouth and tongue
no tears when crying
no wet nappies (diapers) for 3 hours or more
sunken abdomen, eyes, or cheeks
listlessness or irritability
skin that does not flatten when pinched and released
If you suspect that you or your child is dehydrated, call the doctor immediately. Severe dehydration may require hospitalization.
When should a doctor be consulted?
Although usually not harmful, diarrhoea can become dangerous or signal a more serious problem. You should see the doctor if any of the following is true:
You have diarrhoea for more than 3 days.
You have severe pain in the abdomen or rectum.
You have a fever of 102 degrees Fahrenheit or higher.
You see blood in your stool or have black, tarry stools.
You have signs of dehydration.
If your child has diarrhoea, do not hesitate to call the doctor for advice. Diarrhoea can be dangerous in children if too much fluid is lost and not replaced quickly.
What tests might the doctor do?
Diagnostic tests to find the cause of diarrhoea include the following:
Medical history and physical examination. The doctor will need to know about your eating habits and medication use and will examine you for signs of illness.
Stool culture. Lab technicians analyze a sample of stool to check for bacteria, parasites, or other signs of disease or infection.
Blood tests. Blood tests can be helpful in ruling out certain diseases.
Fasting tests. To find out if a food intolerance or allergy is causing the diarrhoea, the doctor may ask you to avoid lactose (found in milk products), carbohydrates, wheat, or other foods to see whether the diarrhoea responds to a change in diet.
Sigmoidoscopy. For this test, the doctor uses a special instrument to look at the inside of the rectum and lower part of the colon.
Colonoscopy. This test is similar to sigmoidoscopy, but the doctor looks at the entire colon.
What is the treatment?
In most cases, replacing lost fluid to prevent dehydration is the only treatment necessary. (See "Preventing Dehydration" below.) Medicines that stop diarrhoea may be helpful in some cases, but they are not recommended for people whose diarrhoea is caused by a bacterial infection or parasite—stopping the diarrhoea traps the organism in the intestines, prolonging the problem. Instead, doctors usually prescribe antibiotics. Viral causes are either treated with medication or left to run their course, depending on the severity and type of the virus.
Dehydration occurs when the body has lost too much fluid and electrolytes (the salts potassium and sodium). The fluid and electrolytes lost during diarrhoea need to be replaced promptly—the body cannot function properly without them. Dehydration is particularly dangerous for children, who can die from it within a matter of days.
Although water is extremely important in preventing dehydration, it does not contain electrolytes. To maintain electrolyte levels, you could have broth or soups, which contain sodium, and fruit juices, soft fruits, or vegetables, which contain potassium.
For children, doctors often recommend a special rehydration solution that contains the nutrients they need. You can buy this solution in the grocery store without a prescription. Examples include Pedialyte, Ceralyte, and Infalyte.
Tips About Food
Until diarrhoea subsides, try to avoid milk products and foods that are greasy, high-fiber, or very sweet. These foods tend to aggravate diarrhoea.
As you improve, you can add soft, bland foods to your diet, including bananas, plain rice, boiled potatoes, toast, crackers, cooked carrots, and baked chicken without the skin or fat. For children, the paediatrician may recommend what is called the BRAT diet: bananas, rice, applesauce, and toast.
Preventing Traveller's Diarrhoea
Traveller's diarrhoea happens when you consume food or water contaminated with bacteria, viruses, or parasites. You can take the following precautions to prevent traveller's diarrhoea when you go abroad:
Do not drink any tap water, not even when brushing your teeth.
Do not drink unpasteurized milk or dairy products.
Do not use ice made from tap water.
Avoid all raw fruits and vegetables (including lettuce and fruit salad) unless they can be peeled and you peel them yourself.
Do not eat raw or rare meat and fish.
Do not eat meat or shellfish that is not hot when served to you.
Do not eat food from street vendors.
You can safely drink bottled water (if you are the one to break the seal), carbonated soft drinks, and hot drinks like coffee or tea.
Depending on where you are going and how long you are staying, your doctor may recommend that you take antibiotics before leaving to protect you from possible infection.
Points to Remember
Diarrhoea is a common problem that usually resolves on its own.
Diarrhoea is dangerous if a person becomes dehydrated.
Causes include viral, bacterial, or parasitic infections; food intolerance; reactions to medicine; intestinal diseases; and functional bowel disorders.
Treatment involves replacing lost fluids and electrolytes. Depending on the cause of the problem, a person might also need medication to stop the diarrhoea or treat an infection. Children may need an oral rehydration solution to replace lost fluids and electrolytes.
Call the doctor if a person with diarrhoea has severe pain in the abdomen or rectum, a fever of 102 degrees Fahrenheit or higher, blood in the stool, signs of dehydration, or diarrhoea for more than 3 days.