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Toxins produced
by Clostridium difficile strains
in the GI tract cause pseudomembranous colitis, typically after
antibiotic use. Symptoms are diarrhea, sometimes bloody, rarely progressing
to sepsis and acute abdomen. Diagnosis is by identifying C. difficile toxin in stool. Treatment
is oral metronidazole or vancomycin.
C. difficile is the most common cause of antibiotic-associated colitis and is typically hospital-acquired. C. difficile–induced diarrhea occurs in up to 8% of hospitalized patients and is responsible for 20 to 30% of cases of hospital-acquired diarrhea. Extremes of age, severe underlying disease, prolonged hospital stay, and living in a nursing home are risk factors.
C. difficile is carried asymptomatically by 15 to 70% of newborns and 3 to 8% of healthy adults and is common in the environment (soil, water, household pets). Disease may result from overgrowth of intrinsic organisms or infection from an external source. Health care workers are frequently the source of transmission.
Antibiotic-induced changes in GI flora are the dominant predisposing factor. Although most antibiotics have been implicated, cephalosporins (particularly 3rd-generation), penicillins (particularly ampicillin , amoxicillin ), and clindamycin pose the highest risk. C. difficile colitis also may follow use of certain antineoplastic agents.
The organism secretes both a cytotoxin and an enterotoxin. The main effect is on the colon, which secretes fluid and develops characteristic pseudomembranes—discrete yellow-white plaques that are easily dislodged. Plaques may coalesce in severe cases. Toxic megacolon, which rarely develops, is somewhat more likely after use of antimotility agents.
Symptoms and Signs
Symptoms typically begin 5 to 10 days after starting antibiotics but may occur on the 1st day or up to 2 mo later. Diarrhea may be mild and semiformed or frequent and watery. Cramping or pain is common, but nausea and vomiting are rare. Limited tissue dissemination occurs very rarely, as do sepsis and acute abdomen. Reactive arthritis has occurred after C.
difficile–induced diarrhea.
Diagnosis
and Treatment
Diagnosis should be suspected in any patient developing diarrhea within 2 mo of antibiotic use or 72 h of hospital admission. Diagnosis is confirmed by stool (sample, not swab) assay for C. difficile toxin. A single sample is usually adequate, but repeat samples should be submitted when suspicion is high and the 1st sample is negative. Fecal leukocytes are often present but not specific.
Metronidazole 250 mg po q 6 h or 500 mg po q 8 h for 10 days is the therapy of choice. If the patient does not respond or relapses, metronidazole as above can be repeated for 21 days, or vancomycin 125 to 500 mg po q 6 h for 10 days may be given. Some patients require bacitracin 500 mg po q 6 h for 10 days, cholestyramine resin, or Saccharomyces boullardii yeast. Relapses occur in 15 to 20% of patients. A few patients have required total colectomy for cure.
Infection control measures are vital to reduce the spread of C.
difficile among patients and health care workers.
Last full review/revision November 2005
Content last modified November 2005
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