Chronic Diarrhea: Causes and Consequences

Chronic Diarrhea
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Frequent diarrhea lasting longer than a few weeks is described as chronic diarrhea, whether it occurs every day or every few days. Chronic diarrhea can be a signal of a serious health condition and, over time, it can cause health problems as well.

Diarrhea is most commonly described as watery stools, but it also means frequent stools (more than three times per day), a substantially larger than normal quantity of stool, or sudden urges to have a bowel movement. If you experience these patterns for several weeks, then you have chronic diarrhea and you should be evaluated by a doctor.

How Diarrhea Develops

The colon, also known as the large intestine, is responsible for forming solid waste from the unabsorbed remains of the food you eat. Fluid is also absorbed into the colon as part of that waste, which allows the stool to pass through the colon more smoothly. Muscles in the colon move the stool along to the rectum for passage out of the body.

When something disrupts this process, causing too much water to be absorbed or the solid waste to pass too quickly through the large intestine, diarrhea can result.

Causes of Chronic Diarrhea

Most people have experienced acute, short-term diarrhea, usually as the result of a gastrointestinal infection. Chronic diarrhea, on the other hand, is less common and is typically caused by medical conditions, allergies, medications, or chronic infections.

  • Medical conditions: Inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis, are common causes of intermittent, chronic diarrhea. Diarrhea, stomach pain, rectal bleeding, fever, and weight loss may occur for weeks or months on end, often resolving for a period of time before recurring. With these conditions, diarrhea alternates with constipation or with what are sometimes called "pencil stools," which are very thin stools. Colon cancer rarely causes any symptoms and is a rare cause of chronic diarrhea accompanied by bloody stools and weight loss.
  • Food sensitivities: Several food sensitivities can cause diarrhea, either due to allergic responses or to intolerance. For example, if you are lactose intolerant, you cannot absorb lactose, which is present in dairy products, and this causes a series of events that result in watery stools. Some foods cause an inflammatory allergic reaction, resulting in excessive water absorption in the colon and diarrhea. Often, with dietary sensitivity, it is unclear whether the cause of the diarrhea is an allergy or difficulty processing the food.
  • Medications: Medications can induce diarrhea, either as an allergic reaction or as a normal medication side effect. You can develop chronic medication-induced diarrhea even if you have already been taking the medicine without problems for years. Antibiotics can also cause infectious diarrhea because they often destroy the normal bacteria that line your intestines, in turn, allowing an infectious organism to flourish.
  • Infections: Sometimes gastrointestinal infections either don't resolve, have a tendency to recur, or are followed by other infections as a result of antibiotic use (even when used as directed), resulting in lingering infections and diarrhea. Parasites, which may not be easily recognized, require specialized medications and can cause chronic diarrhea.
  • Gastric bypass: Gastric bypass surgery, also often referred to as bariatric surgery or weight loss surgery, often results in substantially diminished absorption of food and liquid in the gastrointestinal system, which results in persistent diarrhea.

    Consequences of Chronic Diarrhea

    If you have chronic diarrhea, you can experience serious health problems, even if your diarrhea is caused by a situation that isn't dangerous, such as a food allergy.

    • Nutrition: Chronic diarrhea can cause you to become dehydrated, as your body loses too much fluid. You can also miss out on vitamins, minerals, proteins, and fats when your diarrhea is associated with lack of absorption of these vital nutrients. And, chronic diarrhea can also result in weight loss if you aren't absorbing enough carbohydrates and calories from the food you eat.
    • Bleeding and irritation: Chronic diarrhea can cause irritation of the colon or the rectum, potentially resulting in fragile tissue and bleeding.

    When to See a Doctor

    If you have long-term diarrhea, don't put off seeing your doctor. Your doctor may order blood tests or a stool sample to check for blood in the stool or an infection due to bacteria, a virus, or a parasite. You may need a colonoscopy or flexible sigmoidoscopy, which may identify IBD or early signs of colon cancer. Even if it turns out that you have colon cancer, it is highly curable with long-term survival rates well over 90 percent when detected early.

    Signs that you should see your doctor include:

    • Your diarrhea has lasted for more than two weeks (either intermittently or the entire time).
    • You see blood in or on your stool.
    • You have persistent abdominal cramps or severe pain.
    • You're vomiting a lot.
    • You experience alternating constipation and diarrhea.
    • You notice you're losing weight even though you haven't been trying to.

    A Word From Verywell

    Persistent diarrhea is hard to ignore. Most of the time, the cause is not life-threatening, but the cause and the potential health complications need to be addressed so that you can maintain your energy, nutrition, and a healthy weight.

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