Diarrhea: what it is, causes, and when it is dangerous

Diarrhea is frequent loose stools that in most cases resolves within a few days. The consequences are dangerous: loss of fluid and salts, and a prolonged course often points to a chronic disease. Below is reference information on the mechanisms, symptoms, causes, and tests for diarrhea.

What diarrhea is and its scientific name

The scientific name for diarrhea comes from the Greek for "flowing through." Guideline criteria rely on frequency and volume: loose stools three or more times a day, or defecation (bowel movement) more than twice a day with a volume over 200 milliliters, with pain around the navel and imperative (hard to control) urges. Acute diarrhea lasts up to two weeks, chronic diarrhea four weeks or more. About 1.7 billion people suffer from acute diarrhea each year, and chronic diarrhea occurs in 7–14% of adults. The idea that diarrhea "cleanses" the intestines does not match the description of diarrhea as a pathological condition.

Symptoms of diarrhea

Frequent loose stools are accompanied by cramping abdominal pain, sudden urges, and loss of bowel control. With a viral or bacterial cause, there may be fever, chills, and blood in the stool. Dehydration is recognized by dark, strongly smelling urine or infrequent urination. With a chronic course, vitamin and mineral deficiencies, anemia, and hemorrhoids occur.

• loose watery stools three or more times a day;
• abdominal pain, more often around the navel;
• sudden urges and fecal incontinence;
• fever, chills, blood or pus in the stool with infection;
• dark urine and infrequent urination with dehydration.

Causes of diarrhea: infections, allergies, chronic diseases

The most common causes are intestinal infection and food poisoning. The pathogens are bacteria from contaminated food and water, viruses (influenza, norovirus, rotavirus; in children rotavirus is the leading cause of acute diarrhea), and parasites. Clostridium difficile overgrows after prolonged antibiotic use and hospital treatment; infection from contaminated water during travel is called travelers' diarrhea.

Among non-infectious causes are medications (antibiotics, anticancer drugs, magnesium-containing antacids), food intolerance and allergy, such as lactose intolerance. Diarrhea accompanies diseases of the stomach, small and large intestine: Crohn's disease, ulcerative colitis, celiac disease, diverticular disease, irritable bowel syndrome. Less often it is caused by appendicitis, anxiety, radiation therapy to the pelvic area, and stomach surgery. Sometimes the cause cannot be found.

Why diarrhea occurs in the morning and with influenza

With influenza, diarrhea is one of the possible symptoms along with fever and chills. Guidelines do not single out a separate diagnosis of "morning diarrhea": the list of causes includes irritable bowel syndrome and anxiety, and the motor variant of diarrhea is associated with stress. Chronic diarrhea may be continuous or intermittent.

What tests are done for diarrhea

Examination begins with a physical exam and questions about medications. Then stool and blood tests may be done to look for bacteria, parasites, and signs of disease. For chronic diarrhea the scope is broader: colonoscopy, fecal calprotectin, a test for Clostridium difficile, an ova and parasites test, fecal leukocytes, and a barium X-ray of the lower intestine.

When diarrhea is dangerous and you need to see a doctor

Guideline timeframes differ: a benchmark of 5–7 days, or seeking care for diarrhea lasting more than two days in adults and more than 24 hours in a child. Reasons for consultation are signs of dehydration, blood or pus in the stool, black tarry stool, a temperature of 102 °F (about 38.9 °C) or higher, severe abdominal or rectal pain, bleeding from the anus, and vomiting that prevents keeping fluids down. Diarrhea in an infant requires immediate medical attention.

Diarrhea by itself is not a reason to call an ambulance; 103 or 112 — for bloody vomit or coffee-ground vomit, green vomit, neck stiffness with pain when looking at bright light, sudden severe headache, sudden severe abdominal pain, bluish or pale skin, marked difficulty breathing, or confusion.

This material is for reference and does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer