Nejm 2008;359:1932 (Pseudomembranous Colitis)

Pathophys: Overgrowth and disruption of normal bowel flora, usually after po antibiotics, esp clindamycin; produces toxin

Primarily in hospitalized; emerging importance in institutionalized pts; common after antibiotic use esp in the elderly; worse after 2 or more abx or prolonged course >2 weeks; 25% mortality in elderly

Sx:Fever, abdominal pain, diarrhea, bloody stools

Si:Fever, fecal leukocytes sometimes present

Lab:Stool cytotoxin 95% sens, 99% specif; rapid enzyme immunoassay up to 87% sensitive; culture is not helpful because nontoxic strains exist

Inv:Endoscopy shows plaques and pseudomembranes (eg, “pseudomembranous colitis”)

Rx:

Rehydration and supportive care; cessation of causative antibiotic; 95% respond to po or iv tx with metronidazole or vancomycin for 10 days. Fidaxomicin (Didicid) 200 mg po qd for 10 d; macrolide, FDA approved 2011, same efficacy as oral vanco plus fewer recurrences (Nejm 2011;364:422). Avoid antidiarrheals, as they prolong illness. Bacteriotherapy enemas experimental, have infection risk

Of relapse: common (5-50%); often mild and resolve without tx; may retreat with same abs originally used bcs resistance not typically the cause of relapse.