Update on Clostridium difficile-induced colitis, Part 1

Abstract

Recent findings on the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of Clostridium difficile-induced colitis (CDIC) are discussed. CDIC is a gastrointestinal disorder that results from colonization by and overgrowth of C. difficile. Among patients in the community who are treated with an oral antimicrobial, only 1 to 3 individuals per 100,000 develop CDIC, compared with as many as 1 per 100 hospitalized patients treated with an antimicrobial. The requirements for CDIC are (1) a readily available source of C. difficile; (2) exposure to drugs, most commonly certain antimicrobials, that disrupt the normal colonic microflora; (3) production of the requisite cytotoxins by the C. difficile strain colonizing the colon; and (4) the presence of individual risk factors, including advanced age, severe underlying illness, and a prolonged hospital stay. Among the varied clinical manifestations of CDIC, diarrhea is predominant and is often the sole symptom. In more severe cases, fever and leukocytosis are also present. The formation of pseudomembranous plaques is pathognomonic but relatively infrequent. Presumptive diagnosis is usually based on a positive cytotoxin assay result in the symptomatic patient. Patients who respond to discontinuation of the inciting drug or drugs should not be treated indiscriminately with antimicrobials. Asymptomatic carriers should not be treated, and a period of watchful waiting may be advisable in mild cases. When treatment is necessary, oral metronidazole is the agent of choice in all but the most severe cases. Whether oral metronidazole is therapeutically equivalent to oral vancomycin in severe CDIC is controversial. Regardless of the antimicrobial used, some patients suffer a recurrence of CDIC and a few have several relapses. There have been no comparative studies of treatment for relapsing CDIC. Of the investigational treatments, the tiacumicin macrolides and the yeast Saccharomyces boulardii appear most promising. Diagnostic assays based on the polymerase chain reaction should allow more timely intervention. Health care professionals who improve their understanding of CDIC will be better able to recognize the disorder, select the best treatment, and perhaps reduce the frequency of CDIC in hospitalized patients by working to alter patterns of antimicrobial use.