William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Diarrhea facts
- What is diarrhea?
- How is diarrhea defined?
- Why does diarrhea develop?
- What symptoms are associated with diarrhea?
- What are common causes of acute diarrhea?
- Viral gastroenteritis
- Food poisoning
- Traveler's diarrhea
- Bacterial enterocolitis
- What are common causes of chronic diarrhea?
- What are the complications of diarrhea?
- When should the doctor be called for diarrhea?
- What tests are useful in the evaluation of diarrhea?
- How can dehydration be prevented and treated?
- What is the treatment for diarrhea?
- When should antibiotics be used for diarrhea?
- Find a local Gastroenterologist in your town
Viral gastroenteritis (viral infection of the stomach and the small intestine) is the most common cause of acute diarrhea worldwide. Symptoms of viral gastroenteritis include nausea, vomiting, abdominal cramps, and diarrhea typically last only 48-72 hrs. Unlike bacterial enterocolitis (bacterial infection of the small intestine and colon), patients with viral gastroenteritis usually do not have blood or pus in their stools and have little if any fever.
Viral gastroenteritis can occur in a sporadic form (in a single individual) or in an epidemic form (among groups of individuals). Sporadic diarrhea probably is caused by several different viruses and is believed to be spread by person-to-person contact. The most common cause of epidemic diarrhea (for example, on cruise ships) is infection with a family of viruses known as caliciviruses of which the genus norovirus is the most common (for example, "Norwalk agent"). The caliciviruses are transmitted by food that is contaminated by sick food-handlers or by person-to-person contact.
Food poisoning is a brief illness that is caused by toxins produced by bacteria. The toxins cause abdominal pain (cramps) and vomiting, and also cause the small intestine to secrete large amounts of water that leads to diarrhea. The symptoms of food poisoning usually last less than 24 hours. With some bacteria, the toxins are produced in the food before it is eaten, while with other bacteria, the toxins are produced in the intestine after the food is eaten.
Symptoms usually appear within several hours when food poisoning is caused by toxins that are formed in the food before it is eaten. It takes longer for symptoms to develop when the toxins are formed in the intestine (because it takes time for the bacteria to produce the toxins). Therefore, in the latter case, symptoms usually appear after 7-15 hours.
Staphylococcus aureus is an example of a bacterium that produces toxins in food before it is eaten. Typically, food contaminated with Staphylococcus (such as salad, meat or sandwiches with mayonnaise) is left un-refrigerated at room temperature overnight. The Staphylococcal bacteria multiply in the food and produce toxins. Clostridium perfringens is an example of a bacterium that multiplies in food (usually canned food), and produces toxins in the small intestine after the contaminated food is eaten.
Next: Traveler's diarrhea
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