INTRODUCTION

Chronic diarrhea is defined as loose stools that last for at least four weeks. This usually means three or more loose stools per day. There are many possible causes of chronic diarrhea. Treatment is aimed at correcting the cause of diarrhea (whenever possible), firming up loose stools, and dealing with any complications of diarrhea.

Chronic diarrhea can have a substantial impact on your quality of life and overall health. At its mildest, diarrhea is an inconvenience; at its worst, it may be disabling and even life threatening. Fortunately, effective treatments are available.

This article will focus on causes of chronic diarrhea in developed countries, such as the United States. More detailed information about chronic diarrhea in developed countries is available by subscription. (See "Approach to the adult with chronic diarrhea in developed countries".)

CHRONIC DIARRHEA CAUSES

A wide range of problems can cause chronic diarrhea; some of the most common causes include irritable bowel syndrome, inflammatory bowel disease (Crohn's disease and ulcerative colitis), malabsorption syndromes, and chronic infections. There are also many other less common causes of chronic diarrhea.

Irritable bowel syndrome — Irritable bowel syndrome (IBS) is one of the most common causes of chronic diarrhea. IBS can cause crampy abdominal pain and changes in bowel habits (diarrhea, constipation, or both). IBS can develop after having an infection. (See "Patient information: Irritable bowel syndrome".)

Inflammatory bowel disease — There are several types of inflammatory bowel disease, two of the most common of which are Crohn's disease and ulcerative colitis. These conditions may develop when the body's immune system attacks parts of the digestive tract. (See "Patient information: Crohn's disease" and "Patient information: Ulcerative colitis".)

Infections — Intestinal infections, sometimes called "food poisoning," are an uncommon cause of chronic diarrhea in people who live in developed countries, such as the United States. Infections that cause chronic diarrhea can be seen in people who travel or live in tropical or developing countries, especially older adults and those affected by HIV. Intestinal infections can also develop after eating contaminated food or drinking contaminated water or unpasteurized ("raw") milk. (See "Patient information: Food poisoning (food-borne illness)".)

Endocrine disorders — An overactive thyroid (hyperthyroidism) can cause chronic diarrhea and weight loss. Diabetes can cause chronic diarrhea if the nerves that supply the digestive tract are injured.

Food allergy or sensitivity — Food allergies and hypersensitivity can cause chronic diarrhea. People with celiac disease often have diarrhea and weight loss. (See "Patient information: Celiac disease in adults".)

Medicines — Medicines (prescription and nonprescription), herbs, and dietary supplements can cause diarrhea as a side effect. To determine if a medicine could be the cause of your diarrhea, review your list of medicines with your doctor, nurse, or pharmacist. This information may also be available on the medicine bottle or paperwork that comes with most prescriptions.

CHRONIC DIARRHEA EVALUATION

You should seek medical attention if you have loose or watery stools that last more than four weeks. You may need to be seen sooner than this if you have complications of diarrhea (eg, bloody diarrhea, fever, dehydration, or weight loss).

During your visit, it is important to mention when your diarrhea began, any recent changes in medicines or medical problems, and if you have had accidents (leaking or smearing of stool in the underwear).

Tests — Blood, stool, and urine tests can help to find the underlying cause of diarrhea. If these tests do not find the cause, other approaches may be needed, including X-rays or procedures, such as colonoscopy or sigmoidoscopy. Your primary care provider can order these tests or refer you to a specialist (a gastroenterologist). (See "Patient information: Colonoscopy" and "Patient information: Flexible sigmoidoscopy".)

In some cases, your doctor or nurse will recommend a trial of treatment before more invasive tests (see 'Treatment trial' below).

CHRONIC DIARRHEA TREATMENT

Treatment of chronic diarrhea aims to eliminate the underlying cause (if the cause is known), firm up the bowel movements, and treat any diarrhea-related complications.

Treating the cause — The underlying cause of chronic diarrhea should be found and treated whenever possible. For example, infections may be treated with antibiotics. In people with Crohn's disease or ulcerative colitis, long-term treatment and follow-up is needed.

In some cases, treatment may be as simple as eliminating a food or medicine.

• For people with lactose intolerance, this may include foods or drinks that contain lactose (table 1).
• Other ingredients that are known to cause diarrhea include sugar-free products made with sorbitol and foods made with fat replacements (eg, Olestra®).
• Certain medicines can also cause diarrhea (such as laxatives and antacids).

Treating diarrhea — In some people, the goal is simply to have less diarrhea. This approach is often used before testing, when the results of tests are normal or not helpful, or if diarrhea is caused by a chronic medical problem.

Diarrhea treatments include:

• Bismuth (sold as Kaopectate®, Pepto-Bismol®)
• Treatments that bulk the stools, such as a high-fiber diet or fiber supplement (see "Patient information: High fiber diet")
• Antidiarrhea medicines, such as loperamide (sold as Imodium®, available without a prescription) or prescription medicines, such as diphenoxylate (Lomotil®)
• Octreotide, a prescription medicine that might be given to people with severe diarrhea

Treatment trial — Your doctor or nurse might recommend trying a treatment before further testing. This approach can help to narrow down the list of possible causes of your diarrhea.

Treatments that might be offered include:

• A trial of antibiotics, for an infection
• Stopping a medicine
• Changing your diet, for a possible food allergy or problem absorbing nutrients (such as lactose intolerance)

Treating complications — Chronic or severe diarrhea can lead to potentially serious complications, including dehydration and malnutrition. While you are being evaluated, you should be sure to drink plenty of fluids. You are drinking enough fluids if your urine is a light yellow color.

If you are not able to drink enough fluids and you become dehydrated, you may be given fluids into a vein (IV) to replace the fluids and electrolytes (salts) lost in diarrhea. This will not cure your diarrhea, but it can prevent more serious complications.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed every four months on our Web site (www.uptodate.com/patients).

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information

Patient information: Irritable bowel syndrome
Patient information: Crohn's disease
Patient information: Ulcerative colitis
Patient information: Food poisoning (food-borne illness)
Patient information: Celiac disease in adults
Patient information: Colonoscopy
Patient information: Flexible sigmoidoscopy
Patient information: High fiber diet

Professional level information

Approach to the adult with chronic diarrhea in developed countries
Clinical features and diagnosis of malabsorption
Clinical manifestations and diagnosis of small intestinal bacterial overgrowth
Clinical manifestations, diagnosis, and prognosis of ulcerative colitis in adults
Cryptosporidiosis
Cyclospora infections
Definition of and risk factors for inflammatory bowel disease
Differential diagnosis of microbial foodborne disease
Eosinophilic gastroenteritis
Epidemiology, clinical manifestations, and diagnosis of giardiasis
Etiology and pathogenesis of small intestinal bacterial overgrowth
Evaluation of the HIV-infected patient with diarrhea
Isospora infections
Lactose intolerance
Lymphocytic and collagenous colitis (microscopic colitis)
Medical management of Crohn's disease in adults
Medical management of ulcerative colitis
Overview of the management of Crohn's disease in children and adolescents
Treatment and prevention of giardiasis in adults
Treatment of irritable bowel syndrome

The following organizations also provide reliable health information.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/diarrhea.html)

• National Institute of Diabetes and Digestive and Kidney Diseases

      (http://digestive.niddk.nih.gov/ddiseases/pubs/diarrhea/)

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