Pseudomembranous colitis is a specific infection of the large intestine (colon) due to overgrowth of a bacteria called Clostridium difficile.

The Clostridium difficile bacteria is normally present in the intestine. However, it may overgrow when antibiotics are taken. The bacteria release a powerful toxin that causes the symptoms. The lining of the colon becomes raw and bleeds.

Ampicillin, clindamycin, and cephalosporins are the most common antibiotics associated with this disease in children. Pseudomembranous colitis is rare in infants less than 12 months old because they have protective antibodies from the mother and because the toxin does not cause disease in most infants.

Most cases of pseudomembranous colitis happen while the person is in the hospital because the bacteria can spread from one patient to another.

Risk factors include:

• Advanced age
• Antibiotic use
• Chemotherapy
• Medications that suppress the immune system
• Recent surgery
• Personal history of pseudomembranous colitis

• Abdominal cramps
• Bloody stools
• Low-grade fever
• Urge to have a bowel movement
• Watery diarrhea

Either or both of the following tests will confirm the disorder:

• Colonoscopy or flexible sigmoidoscopy
• Immunoassay for C. difficile toxin