Causes of diarrhea

Causes of diarrhea include bacteria, viruses or parasites, certain medicines, food intolerances and diseases that affect the stomach, small intestine or colon. In many cases, no cause can be found. The most common causes of diarrhea include:

1. Viruses - Viral infections such as the Rotavirus, Adenovirus, Enterovirus, Norwalk virus, cytomegalovirus, viral hepatitis and the herpes simplex virus can cause diarrhea. Rotavirus is the most common cause of acute childhood diarrhea.

2. Bacteria and parasites - Contaminated food or water can transmit bacteria and parasites to your body, which is common when travelling in developing countries (called traveller's diarrhea). Parasites such as Giardia lamblia and Cryptosporidium can cause diarrhea. Bacterial causes of diarrhea include Campylobacter, Salmonella, Shigella and Escherichia coli.

3. Medications - Many medications, especially antibiotics, can cause diarrhea. Antibiotics destroy both good and bad bacteria, which can disturb the natural balance of bacteria in your intestines, which can also cause diarrhea. Certain medications such as NSAIDs, antacids, antihypertensives, antibiotics and antiarrhythmics can also cause diarrhea in some people. Finally, radiation therapy may bring on episodes of diarrhea.

Other causes of diarrhea

Diabetes - Diabetes mellitus may be associated with diarrhea due to nerve damage and bacterial overgrowth and occurs mainly in people with long-standing, poorly-controlled diabetes.

Digestive disorders - Chronic diarrhea has a number of other causes, such as Crohn's disease, ulcerative colitis, celiac disease and irritable bowel syndrome. Other less common causes include ischemia of the gut, infections, and colon cancer or polyps.

Food intolerance - Recent dietary changes can also lead to acute diarrhea (coffee, tea, colas, dietetic foods, gums or mints). Additionally, carbohydrate malabsorption can develop into either lactose, sorbitol, or fructose intolerance. Lactose, a sugar found in milk and dairy products, and can trigger diarrhea in some people. Fructose, a sugar found in many fruits, is a common cause of diarrhea, especially in children. Artificial sweeteners found in chewing gum and other sugar-free products (sorbitol and mannitol) can cause diarrhea in otherwise healthy people.

Maldigestion or malabsorption syndromes - These types of medical conditions typically cause fatty stools which are characterised by bulky, greasy or very bad smelling stools. Chronic pancreatitis (caused by alcohol abuse, cystic fibrosis, hereditary pancreatitis, trauma to the pancreas and pancreatic cancer) can lead to maldigestion and fatty stools. Biliary tract obstruction, cholestatic liver disease, and bacterial overgrowth can also lead to maldigestion problems.

Celiac disease, or gluten sensitive enteropathy is the most common small bowel disease causing malabsorption. Additional common causes of malabsorption include small bowel mucosal diseases or surgical resection of the small bowel. Whipple's disease, tropical sprue and Zollinger-Ellison syndrome, are very uncommon and rare conditions that can lead to malabsorption.

Surgery - Abdominal surgery or gallbladder removal surgery can trigger bouts of diarrhea.

When to seek help
Although usually not harmful, diarrhea can become dangerous or signal a more serious problem. You should see your doctor if diarrhea persists for more than a couple of days. You should also talk to your doctor if you feel ill, have a strong pain in your abdomen or rectum, a fever, blood or mucus in your stools, severe diarrhea for more than three days or symptoms of dehydration. If your child has diarrhea, do not hesitate to call the doctor for advice, as diarrhea can be dangerous in children, leading to fast dehydration and electrolyte imbalance.

The first step to treating diarrhea is to seek a diagnosis. But how doctors diagnose diarrhea and what tests or procedures can you expect if you visit a doctor's office with this common complaint? Continue reading the next section on how to diagnose diarrhea to learn to stop diarrhea.