Review Question - QID 103519

This patient is presenting with Clostridium difficile (C. difficile) colitis, which is characterized by pseudomembranous colitis on histology as demonstrated in figure D.

C. difficile is a gram positive bacterial infection causing pseudomembranous colitis which often presents with recurrent, watery, foul smelling diarrhea. It is often caused by recent antibiotic use, especially clindamycin or ampicillin. C. difficile has a wide range of severity from mild diarrhea to severe-life threatening diarrhea and colitis. Treatment is either metronidazole or PO vancomycin depending upon severity of symptoms. On histology, pseudomembranous colitis is observed, which is characterized by small surface erosions of the superficial colonic crypts and overlying accumulation of neutrophils, fibrin, mucus and necrotic epithelial cells.

Schroeder reviews the prevalence and treatment of C. difficile associated diarrhea. He states that C. difficile infection is responsible for approximately 3 million cases of diarrhea and colitis annually in the United States. The mortality rate is 1 to 2.5 percent. Early diagnosis and prompt aggressive treatment are critical in managing C. difficile-associated diarrhea. Treatment of C. difficile-associated diarrhea includes discontinuation of the precipitating antibiotic (if possible) and the administration of metronidazole or vancomycin.

Korman reviews the management of C. difficile, especially severe C. difficile. She states oral vancomycin and metronidazole have been the recommended antimicrobial therapy options, and fidaxomicin is an effective new alternative. There is ongoing concern regarding the potential inferiority of metronidazole, in particular for severe C. difficile. Biological therapies for the restoration of the intestinal microbiota (e.g., fecal microbiota transplantation) and monoclonal antibody therapy are promising approaches for C. difficile management, in particular for troublesome recurrent C. difficile.

Figures are described in the Incorrect Answer choice explanations below. Illustration A demonstrates the histological findings in C. diff.

Incorrect Answers:
Answer 1: Figure A demonstrates the histology that would be observed in Crohn's disease. Note the non-caseating granuloma which is characteristic of Crohn's.
Answer 2: Figure B demonstrates the histology that would be seen on normal large bowel biopsy.
Answer 3: Figure C demonstrates the large bowel histology that would be observed in ulcerative colitis. Note the crypt abscesses and ulcers.
Answer 5: Figure E demonstrates the small bowel histology that would be observed in celiac sprue. Note the blunting of the villi and crypt hyperplasia.