Diarrhea is characterized by loose, watery stools occurring three or more times a day. While many instances of diarrhea resolve within a few days, it is considered persistent when it lasts for two weeks or longer. This extended duration can point to various underlying issues within the digestive system or broader bodily functions. This article explores several factors that can contribute to diarrhea lasting for an extended period.
Infectious Agents
Infectious organisms commonly cause digestive upset, with some leading to persistent diarrhea. Bacterial infections, such as Salmonella, Campylobacter, Shigella, and certain E. coli strains, can disrupt the intestinal lining, leading to inflammation and fluid secretion. Clostridioides difficile (C. difficile) is another bacterium causing persistent diarrhea, often emerging after antibiotic use when gut flora is disturbed.
Viral infections, while often acute, can sometimes cause lingering symptoms, especially in certain individuals. Viruses like rotavirus and norovirus, though typically brief, may contribute to extended digestive discomfort in some cases.
Parasitic infections are known for causing long-lasting diarrhea due to their prolonged presence within the digestive tract. Common parasitic culprits include Giardia lamblia, Cryptosporidium, and Entamoeba histolytica. These parasites can damage the intestinal lining or interfere with nutrient and water absorption, resulting in persistent watery stools. Identifying the specific infectious agent often requires stool tests to guide targeted treatment.
Dietary Triggers and Sensitivities
Certain foods or dietary components can provoke persistent diarrhea. Food intolerances, such as lactose intolerance (lack of the enzyme lactase for dairy sugar) or fructose intolerance (difficulty digesting fruit sugar), cause osmotic diarrhea when undigested sugars draw excess water into the intestines.
Celiac disease is an autoimmune condition where consuming gluten, a protein found in wheat, barley, and rye, triggers an immune response that damages the small intestine. This damage impairs nutrient absorption and frequently results in chronic diarrhea. A strict, lifelong gluten-free diet is necessary to manage this condition and allow the intestine to heal.
Artificial sweeteners like sorbitol and xylitol, found in sugar-free foods, can also cause osmotic diarrhea if consumed in large quantities, as they are poorly absorbed and draw water into the bowel. Excessive caffeine intake or a high-fat diet may also contribute to persistent loose stools.
Chronic Digestive Conditions
Long-term medical conditions affecting the digestive system frequently cause persistent diarrhea. Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain, bloating, and altered bowel habits, including diarrhea-predominant IBS. This condition is chronic, meaning symptoms can fluctuate but often require ongoing management.
Inflammatory Bowel Disease (IBD) encompasses chronic inflammatory conditions of the digestive tract, primarily Crohn’s disease and ulcerative colitis. These conditions involve immune system overactivity, leading to intestinal lining inflammation and damage, commonly manifesting as persistent diarrhea, abdominal pain, and weight loss.
Microscopic colitis is another inflammatory condition of the colon, where inflammation is only visible under a microscope. It typically causes watery, persistent diarrhea and can be associated with autoimmune diseases or certain medications.
Diverticulitis, inflammation of small pouches in the colon wall, can also alter bowel habits, including diarrhea. Inflamed pouches irritate the area and disrupt water absorption, contributing to loose stools.
Medication Side Effects and Other Factors
Various medications can cause diarrhea as a side effect. Antibiotics, for instance, can disrupt gut bacteria balance, leading to diarrhea by allowing harmful bacteria like C. difficile to overgrow or by directly affecting intestinal function. Other common culprits include antacids containing magnesium, nonsteroidal anti-inflammatory drugs (NSAIDs), certain blood pressure medications, and chemotherapy drugs.
Endocrine disorders can also influence bowel function. Hyperthyroidism, where the thyroid produces too much hormone, can accelerate metabolism and gut transit time, leading to frequent bowel movements and diarrhea. This increased speed reduces water absorption time, resulting in loose stools.
The gut-brain axis means psychological stress and anxiety can contribute to functional diarrhea. Brain signals affect gut motility and sensation, leading to symptoms even without an underlying physical cause.
Other less common factors include malabsorption syndromes like exocrine pancreatic insufficiency, where the pancreas doesn’t produce enough digestive enzymes, leading to undigested food. Post-surgical changes to the digestive tract can also alter bowel function and cause persistent diarrhea.