Intestinal Disorders Diarrhea

Diarrhea describes loose stools and watery bowel movements, sometimes accompanied by unusual stool color, odor, frequency and volume. Diarrhea is a symptom of underlying causes, and not an independent health condition.

Chronic diarrhea describes diarrhea and loose stools that persist for longer than four weeks. When left untreated, chronic diarrhea causes serious health complications, including electrolyte imbalance and dehydration. Whether acute or chronic, diarrhea in infants and the elderly can quickly cause dehydration.

Diarrhea Causes

Many diarrhea causes exist, but viral gastroenteritis is perhaps the most common acute diarrhea cause. Often called “stomach flu,” viral gastroenteritis causes diarrhea and sometimes fever, but usually resolves within a few days.

Infectious diseases can be either acute or chronic causes of diarrhea. Parasites, bacterial infections and viral infections can all be responsible for loose stools. Bacterial infections that cause diarrhea include Salmonella enteritidis and Escherichia coli. Chronic diarrhea cases also include the viral agents HIV, Norwalk agent, and rotavirus.

Non-Infectious Diarrhea Causes

Non-infectious diarrhea causes cover many different conditions. Food poisoning, food allergies and food additives may trigger attacks of acute diarrhea. Malabsorption syndromes such as gluten or lactose intolerance can also trigger acute diarrhea.

Travel is often a factor in attacks of both acute and chronic diarrhea. Acute diarrhea related to travel may be triggered by disruptions in the normal schedule of eating, exercising and resting.

Eating food or drinking water contaminated with fecal matter are common chronic diarrhea causes when traveling to underdeveloped countries. Many infectious chronic diarrhea causes are encountered through contact with contaminated food when traveling.

Medical Diarrhea Causes

Numerous medications list diarrhea or loose stools among their side effects. Medications commonly associated with diarrhea include antibiotics, magnesium-based laxatives, high blood pressure medications and certain chemotherapy drugs. Abdominal radiation therapy and abdominal surgery can also trigger chronic diarrhea.

Medical causes of diarrhea can include:

  • abdominal trauma
  • celiac disease
  • Crohn’s disease
  • diabetes
  • diverticular disease
  • endocrine disorders
  • fecal impaction
  • gallbladder disorders
  • hereditary factors
  • intestinal obstructions
  • irritable bowel syndrome
  • pancreas disorders
  • reduced intestinal blood flow
  • thyroid disorders
  • tumors
  • ulcerative colitis.

Diagnosing Diarrhea

A diagnosis of persistent diarrhea begins with a detailed medical history. Provide your doctor with as much information as you can, including:

  • any accompanying abdominal pain, nausea, or vomiting
  • any contact with potentially contaminated food or water
  • changes in appetite
  • changes in weight
  • consistency, color and odor of loose stools
  • contact with people with infectious diarrhea
  • duration, severity and frequency of loose stools
  • medications (both prescription and nonprescription)
  • pre-existing medical conditions
  • recent travel
  • when diarrhea symptoms began.

A physical exam will explore the abdominal region for possible diarrhea causes. Expect a digital rectal exam, where the doctor palpates the inside of the rectum with a gloved, lubricated finger.

During diagnosis, stool, blood and urine tests may be required to evaluate possible dehydration or electrolyte imbalance. Chronic diarrhea may require several stool samples, x-rays or endoscopic examinations to rule out or confirm diarrhea causes.

Treatment of Diarrhea

Acute cases of diarrhea usually resolve by themselves, although care must be taken to avoid dehydration. As diarrhea is a symptom, treating underlying diarrhea causes often is necessary for diarrhea relief. Infectious diarrhea, for instance, is often treated with antibiotics.

During treatment of diarrhea, loose stools, dehydration, and other diarrhea symptoms may be treated directly to provide some symptom relief. Adding bulk and fiber to the diet may reduce loose stools in some people, although adding too much fiber too quickly can sometimes worsen diarrhea symptoms.

Adequate salt, sugar and fluid intake is vital to prevent dehydration and electrolyte imbalance during attacks of diarrhea. Despite popular belief, sports drinks and clear broths are insufficient to prevent dehydration caused by severe or chronic diarrhea.

To prevent dehydration, your doctor may recommend over-the-counter oral rehydration solutions (ORS). ORS products contain the correct mix of fluids, sugar, salt and other elements required to fight dehydration and prevent electrolyte imbalance.

Antidiarrheal medications are available in both prescription and nonprescription forms. However, diarrhea medication should be used only after consulting a doctor, as these medications can worsen some diarrhea-causing infections.

Preventing Diarrhea

Diarrhea can’t always be avoided or prevented, but some strategies for reducing your risk of diarrhea include:

  • avoiding alcohol and caffeine
  • avoiding the use of ice when traveling
  • drinking only bottled or purified water when traveling
  • washing your hands regularly
  • using hygienic food-handling techniques.

When traveling in underdeveloped countries, avoid eating the following foods: raw shellfish, undercooked meat, dairy products, raw vegetables and fruit without peels.

Electrolyte Imbalance, Dehydration, and Diarrhea

The watery, loose stools associated with diarrhea rob the body of fluids and can result in dehydration. Severe dehydration causes a dangerous medical condition known as electrolyte imbalance. A person with electrolyte imbalance has insufficient amounts of the elements sodium, potassium, magnesium and calcium. Electrolyte imbalance is a serious medical condition requiring prompt treatment to avoid seizures, coma and death.


American Academy of Family Physicians. (nd). Health tools: Diarrhea.

American Academy of Family Physicians. (updated 2002). Vomiting and diarrhea: Helping your child through sickness.

Beers, M.H.