Cause:Clostridium difficile
Pathophys:Proliferates when there is suppression of normal bowel flora by various broad-spectrum antibiotics; cytotoxic toxin production. IgG antibody to the toxin develops variably and is protective (Nejm 2000;342:390)
Associated with antibiotic rx, usually broad-spectrum types and esp clindamycin, and/or cancer chemoRx. Also the cause of 20% of all antibiotic-associated diarrhea without pseudomembranous colitis
Prevalence increasing in 2006 due to quinolone selection of a strain that produces higher toxin levels
Sx:H/o antibiotic use, esp cephalosporin or clindamycin >6 d before loose but not watery diarrhea onset; occasionally fever, abdominal pain
Si:Raised plaques (pseudopolyps) on sigmoidoscopy or colonoscopy, "swollen rice grains," bleed when scraped; rectum may be spared often
Lab:
Bact:Fecal leukocytes by methylene blue stain or Gram stain of stool
Chem:Toxin A and B in stool by various methods; by tissue culture assay, 94-100% sens, 99% specif; by latex agglutination assay (poorest test but most often used), 50% sens, 99% specif; by enzyme-linked methods, 75% sens, 99% specif; order if positive fecal leukocytes stain
Hem:Increased polys, often 20 000-60 000/mm3
Rx:
(Med Let 2006;48:89)
Prevent by restricting clindamycin use (Ann IM 1994;120:272)
of colitis:
Of recurrences (Jama 2009;301:954): Vancomycin 125 qid × 1 wk, then bid × 1 wk, then qd × 1 wk, then qod × 1 wk, then q 3 d × 3 wk. If quinolone-resistant strains (Nejm 2005;353:2433, 2443), which recur frequently, rifaximine (Xifaxan) 300 mg po bid or tolevamer, or nitazoxanide (Alinia). Perhaps monoclonal antibodies iv; decr recurrence rate from 25% to 7% (Nejm 2010;362:197). Avoid agents that slow gi motility, eg, Lomotil, narcotics