Digestive Basics - Diarrhea

Part 2 - Tests for the cause of diarrhea, and treatments.

Although usually not harmful, diarrhea can become dangerous or signal a more serious problem. You should see the doctor if:

• You have diarrhea 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 diarrhea, do not hesitate to call the doctor for advice. Diarrhea can be dangerous in children if too much fluid is lost and not replaced quickly.

Diagnostic tests to find the cause of diarrhea 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 diarrhea, the doctor may ask you to avoid lactose (found in milk products), carbohydrates, wheat, or other foods to see whether the diarrhea 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.

In most cases, replacing lost fluid to prevent dehydration is the only treatment necessary. (See "Preventing Dehydration" below.) Medicines that stop diarrhea may be helpful in some cases, but they are not recommended for people whose diarrhea is from a bacterial infection or parasite--stopping the diarrhea 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 diarrhea 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 should also have chicken or beef broth, which contains sodium, and fruit and cola drinks, 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.

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Until diarrhea subsides, try to avoid milk products and foods that are greasy, high-fiber, or very sweet. These foods tend to aggravate diarrhea.

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 pediatrician may recommend what is called the BRAT diet: bananas, rice, applesauce, and toast.

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