Diarrhea is a frequent symptom of intestinal infection and inflammatory response. People are typically well aware when they are experiencing diarrhea. There is a more than usual amount of bowel movements with the stool being softer or more liquid than normal. Depending on the cause of the diarrhea, the stool may contain blood, mucus or excessive amounts of fat. When diarrhea is excessive or accompanied by vomiting, dehydration may occur and fluids will need to be replaced.
Bacterial Infections
There are many bacterial causes of diarrhea including Salmonella, Shigella, E. coli, cholera and Campylobacter are a few examples. These microorganisms are usually acquired by consuming undercooked or raw food and dairy and drinking contaminated water. Most bacterial causes of diarrhea resolve on its own without antibiotic treatment. Certain high-risk patients such as newborns and infants may require antibiotics to treat the infection and prevent dehydration, however.
Viral Infections
Viral causes of diarrhea are also acquired through contaminated food or water. Common viral causes of diarrhea include rotaviruses and noroviruses. Rotavirus can cause severe diarrhea in children and, according to the U.S. Centers for Disease Control and Prevention (CDC), more than 500,000 children worldwide die as a result of this infection. There is a vaccine available to prevent children from getting infected with this virus. Noroviruses are what people generally call the 24-hour stomach flu. It is commonly read about in the newspapers when there is an outbreak of gastrointestinal illness on cruise ships.
Parasitic Infections
Many parasites that infect humans can cause diarrhea as one of the symptoms; however, with protozoan parasites such as Giardia and Cryptosporidium, the main symptom is acute and chronic diarrhea. People get infected with these two parasites through ingesting contaminated water. Giardia infection, which is also common in young children in day care settings, is characterized by intestinal gas and foul-smelling, greasy stools that will float in the toilet.
Medicine
Certain medications such as antibiotics have been implicated in non-infectious disease diarrhea. Antibiotics can cause diarrhea because the drug may disrupt the normal intestinal bacteria. This is a common side effect of many antibiotics. Sometimes antibiotic usage, particularly in the hospital setting, can cause more severe disease. Pseudomembraneous colitis as a result of overgrowth and toxin production of Clostridium difficile can cause life-threatening diarrhea.
Intestinal Disorders and Diseases
Crohn's disease, irritable bowel syndrome (IBS) and celiac disease can all lead to diarrhea. Crohn's disease is an inflammation of the gastrointestinal tract which is characterized swelling that causes diarrhea. IBS is a common disorder of the intestines that results in cramping and diarrhea. Diet and controlling stress are two things that can be done to minimize the effects of IBS. Celiac disease is a genetic disease that is associated with the ingestion of gluten.
References
- Koneman's Color Atlas and Testbook of Diagnostic Microbiology, 6th Ed., Elmer Koneman, M.D.
- CDC: Giardia
- CDC: Rotavirus
