View source for WBR1115

{{WBRQuestion
|QuestionAuthor={{M.P}}
|ExamType=USMLE Step 3
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|MainCategory=Emergency Room
|MainCategory=Emergency Room
|SubCategory=Gastrointestinal
|Prompt=A 50 year old male comes to the emergency department with complaints of abdominal pain, loose watery stools and fever for the past 2 days.  The patient has no nausea and vomiting and denies any blood or mucus in stools.  His past history is significant for treatment of upper respiratory tract infection with penicillin two weeks back.  He denies any recent travel outside the country or contacts with sick patients.  He is a known diabetic and hypertension on regular medications.  He is not a smoker and does not consume alcohol.  On examination his vitals are pulse: 102/min, BP: 110/80 mmHg, temperature: 38 degree Celsius. His mucus membrane is dry.  Abdominal examination reveals diffuse tenderness and active bowel sounds with no distension.  Initial lab evaluation shows Hb: 12 g/dl, RBC: 4.5 million/mm3, WBC: 18,000/mm3, sodium: 147 mEq/L, potassium: 3 mEq/L, chloride: 107 mEq/L, BUN: 50 mg/dl, serum creatinine: 2 mg/dl and serum albumin 2.5 g/dl.  Which of the following would be the most appropriate next step in the management of this patient? 
|Explanation=[[Clostridium difficile]] infection (CDI) is defined as the acute onset of [[diarrhea]] (≥ 3 unformed stools in ≤24 hours) with either documented toxigenic Clostridium difficile (C. difficile) or its toxin, or colonoscopic or histopathological findings of pseudomembranous colitis in the absence of any other documented cause of diarrhea.  Patients with typical manifestations of C. difficile and a positive diagnostic assay should receive antibiotics for treatment for C. difficile.  Empiric therapy with metronidazole or vancomycin can be started if the clinical suspicion is high.  Therapy for non-severe C. difficile infection (CDI) usually consists of oral [[metronidazole]] for 10-14 days and oral [[vancomycin]] is given if there is no response to oral metronidazole or in case of any allergy to sulfa drugs.  Severe C. difficile infection (CDI) is defined when patient develop signs of systemic toxicity with white blood cell count  >15,000 cells/microL or a serum creatinine level ≥1.5 times the premorbid level or serum albumin <2.5 mg/dL (25 g/L).  Oral vancomycin (125 mg four times daily) is the preferred therapy for severe or refractory cases and sometimes higher dosing of vancomycin (500 mg four times daily) with rectal and nasogastric formulations can be used especially when there is complicated disease with peritoneal signs and abdominal distension.
|AnswerA=Stool studies for Clostridium difficle toxin

|AnswerAExp=Empiric therapy with [[metronidazole]] or [[vancomycin]] can be started if the clinical suspicion is high.
|AnswerB=Oral metronidazole


|AnswerBExp=Therapy for non-severe C. difficile infection (CDI) usually consists of oral metronidazole for 10-14 days.  This patient has severe C. difficile infection and hence should be treated with vancomycin. 
|AnswerC=Oral vancomycin

|AnswerCExp=Oral vancomycin (125 mg four times daily) is the preferred therapy for severe or refractory cases and hence the right option.
|AnswerD=Intravenous metronidazole

|AnswerDExp=Intravenous metronidazole is used along with oral vancomycin in the treatment complicated disease with peritoneal signs and abdominal distension.
|AnswerE=Colonoscopy and biopsy
|AnswerEExp=Treatment should be promptly initiated in patients with severe C. difficile infection with high clinical suspicion. 
|EducationalObjectives=Empiric therapy with antibiotics should be started if the clinical suspicion of CDI is high.  Oral [[vancomycin]] is the drug of choice for severe CDI. 
|RightAnswer=C
|WBRKeyword=[[Clostridium difficile]] 
|Approved=Yes
}}