pseudomembranous colitis

Alternative names 

Antibiotic associated colitis; Colitis - pseudomembranous; Necrotizing colitis 
Definition 

Pseudomembranous colitis is a complication of antibiotic therapy that causes severe inflammation (irritation and swelling with presence of excess immune cells) in areas of the colon.

Causes, incidence, and risk factors 

Almost any antibiotic can cause this condition. Clostridium difficile, which occurs normally in the intestine, overgrows when antibiotics are taken. This bacteria releases a powerful toxin which then causes the symptoms. The lining (mucosa) of the colon becomes raw and bleeds (hemorrhagic). Risk factors are antibiotic usage, chemotherapy for cancer, advanced age, recent surgery, and history of previous pseudomembranous colitis.

Ampicillin is the most common antibiotic associated with this disease in children. Pseudomembranous colitis is rare in infants less than 12 months old because of the presence of protective maternal antibodies. 
Symptoms  

Watery diarrhea 
Urge to defecate 
Abdominal cramps 
Low-grade fever 
Additional symptoms that may be associated with this disease: 
Stools, bloody 
Abdominal pain 
Signs and tests  

Either or both of the following tests will confirm the disorder: 
A stool culture positive for C. difficile toxin 
A colonoscopy showing pseudomembranous colitis (a characteristic appearance of the colon) 
Treatment 

The antibiotic causing the condition should be stopped. Metronidazole is usually used to treat the disorder, but oral vancomycin can also be used. Rehydration with oral electrolyte solutions or intravenous therapy may be indicated to replace fluids lost by diarrhea. In rare cases surgery is required to treat infections that worsen or do not respond to antibiotics. 
Expectations (prognosis)

The outcome is generally good without complications.