Snapshot A 50-year-old female is hospitalized for a course of intravenous clindamycin to treat an abscess. Four days later she develops a watery diarrhea with > 3 stools /day. Temperature is 102.2°F (39°C). Physical exam reveals abdominal tenderness with no guarding. Her WBC is 15,000 mm³ with a positive fecal leucocyte test. Sigmoidoscopy reveals 0.2-2 cm raised adherent yellow plaques. Introduction Classification bacteria gram-positive bacilli spore-forming Clostridium C. difficile Presentation Antibiotic-associated diarrhea affects hospitalized adult patients most commonly tested causative antibiotics clindamycin "Linda gives me diarrhea" ampicillin cephalosporins amoxicillin bacteria are non-invasive Fever, abdominal pain Fecal RBCs and WBCs Most commonly causes colitis but may involve small bowel Complications toxic megacolon Evaluation Test for C. difficile toxin in stool Pseudomembranes on sigmoidoscopy Differential Infectious diarrhea: S. aureus, C. perfringens Non infectious diarrhea: Crohn's disease, irritable bowel syndrome Acute abdomen: small bowel ileus, volvulus Treatment Conservative discontinue inciting antibiotic indication this is an important initial step when treating patients with C. difficile infection Medical metronidazole indication oral metronidazole is used for non-severe C. difficile infection oral metronidazole can be used for initial recurrence of non-severe C. difficile infection vancomycin indication oral vancomycin is used for non-severe and severe C. difficile infection oral vancomycin can be used for second recurrence of non-severe C. difficile infection fidaxomicin can be used as an alternative oral vancomycin in addition to intravenous metronidazole in patients who are critically ill with fulminant or refractory disease Prognosis, Prevention and Complications Recurrences occur in 25% of cases after completion of antibiotic therapy repeat PO metronidazole or vancomycin fidaxomicin is an acceptable alternative