Diarrhea is defined as loose, watery stools that occur frequently, according to Medline Plus. Diarrhea is usually mild and resolves quickly, but when it lasts for more than four weeks, it is considered chronic. There are many possible causes for diarrhea, which can quickly cause dangerous dehydration in infants, children and the elderly.
Viral Gastroenteritits
Gastroenteritis is an inflammation of the stomach and intestines that causes diarrhea and vomiting. Viral gastroenteritis is caused by viruses such as rotovirus and norovirus, and is commonly referred to as "stomach flu," according to the U.S. Centers for Disease Control and Prevention. Besides diarrhea and vomiting, symptoms of can include abdominal cramping, headache and fever. Viral gastroenteritis is contagious and is spread through contaminated food and utensils, and close contact with infected people. It can be life-threatening to infants, children, elderly persons and those with immune disorders if fluids lost through vomiting and diarrhea are not replaced. Treatment includes prevention of dehydration. The CDC recommends oral rehydrating solutions available over-the-counter for those at high risk for dehydration.
Irritable Bowel Syndrome
Sufferers of irritable bowel syndrome, or IBS, experience abdominal pain and changes in bowel habits not explained by commonly known causes, according to the journal "American Family Physician." It is estimated that 10 to 15 percent of the population is affected by IBS. A diagnosis of IBS may be made if abdominal pain or discomfort has occurred for 12 weeks during the previous 12 months, accompanied by relief of pain after a bowel movement, increase or decrease in the frequency of bowel movements and a change in their appearance. Additional symptoms include alternating diarrhea and constipation, passage of white mucus with a bowel movement and abdominal bloating. These symptoms can also indicate other serious disorders and should be evaluated by a physician.
Ulcerative Colitis
Ulcerative colitis causes sudden and severe diarrhea that may be bloody, abdominal cramps and fever that result from inflammation of the colon, or large intestine. The cause of ulcerative colitis is unknown, explains the Merck Manual Online Medical Library. Flare-ups can cause severe symptoms and profound illness. Complications include anemia from blood loss, inflammation of the spine, pelvic joints and eyes, colon cancer, and an expansion and possible rupture of the colon, called toxic megacolon. Treatment is based on control of symptoms and includes dietary restrictions and supplements, medications to control inflammation and diarrhea and drugs that inhibit the immune system to reduce damage to the colon.
