Colitis (cont.)

All types of colitis are associated with inflammation of the colon, though some types may be more severe and potentially dangerous than others. When a patient complains of pain and diarrhea with or without bloody stool, it is important to diagnose the type of colitis since treatments are different for the different types of colitis.

Many bacteria normally reside in the colon; they live in harmony with the body and cause no symptoms. However, if disease-causing bacteria are ingested with bacteria-contaminated foods, these bacteria may infect the small intestine and/or colon. Common infecting bacteria include:

• Campylobacter,
  
  
• Shigella,
  
  
• E. Coli, and
  
  
• Salmonella.

These infections, with the exception of Campylobacter infection, often cause bloody diarrhea and can lead to dehydration from the loss of fluids in the diarrheal stools. Similar symptoms can be seen with viral and parasitic infections, though common viral infections of the gastrointestinal tract more often involve infection of the small intestine rather than the colon.

Sometimes colitis may occur after antibiotics have been prescribed for an infection elsewhere in the body. The antibiotic suppresses some of the normal bacteria within the colon and allows an overgrowth of another type of bacteria, some of which can lead to colitis. Most commonly the bacterium that overgrows is a bacterium called, Clostridium difficile (C. difficile, C. diff). This bacteria produces toxins that cause diarrhea, usually non-bloody, associated with a fever and is called C. difficile colitis or pseudomembranous colitis (because of the membrane-like clumps of pus that form on the inner lining of the colon).

Source: MedicineNet.com
http://www.medicinenet.com/colitis/article.htm