Natasha Press, MD, FRCPC (biography and disclosures)
What I did before
Clostridium difficile infection (CDI) can range from asymptomatic carriage, to mild or moderate diarrhea, to fulminant and sometimes fatal pseudomembranous colitis. Risk factors for CDI include antibiotic use, duration of hospitalization, and age >65. In the past few years, a hypervirulent strain of C. difficile, called NAP-1, has caused hospital outbreaks that have been unusually severe and recurrent.
What changed my practice
Clinical practice guidelines, published in 2010, by the Infectious Diseases Society of America, provide treatment recommendations for initial and recurrent episodes of C. difficile. The guidelines are available free online at www.idsociety.org. They help to clarify when to use oral vancomycin versus oral metronidazole, and how to treat recurrences, which occur in 20% of patients.
What I do now
The guidelines have changed my practice in 6 ways:
- In the hospital, when a patient has a high white blood count, I order a stool test for C. difficile. Most patients with CDI will have diarrhea, and may have abdominal discomfort or fever, but some patients will present with leucocytosis, which prompts me to consider CDI, in addition to other causes.
- If a patient has severe CDI, I prescribe oral vancomycin 125 mg po qid x 14 days. Severe CDI is defined as a WBC>15 or creatinine >1.5x above baseline. (“Severe” can also include older patients, particularly if they are febrile or have a low albumin). For patients with mild to moderate CDI (normal WBC and creatinine), I prescribe metronidazole 500 mg po tid x 14 days. When I see patients in my office, and I’m not sure if their CDI is severe or not, I will send them for bloodwork to determine their WBC and creatinine.
- If a patient has a recurrence of CDI after I’ve treated them, I again consider whether or not it’s severe. If it’s severe, I prescribe oral vancomycin just like I did for their initial episode. Sometimes patients who’ve initiated treatment for CDI in hospital, follow-up with their family doctor after discharge. Once the patient has completed treatment, no further investigations are required. However, if their diarrhea recurs, then they should be re-tested for C. difficile. Different labs do different types of testing for C. difficile, but all the tests detect the toxin-producing C. difficile, so you don’t have to specify which type of test you want. If patients have a second recurrence, they can receive a longer course of vancomycin as described in the guidelines. For the longer course, the vancomycin dose is tapered, then pulsed. At this point, family physicians may decide to refer the patient to a specialist (infectious diseases or gastroenterology).
- If a patient is very sick with CDI, and has hypotension or ileus or toxic megacolon, I ask for a surgical consult, and order a higher dose of oral vancomycin (500mg po qid) and add IV metronidazole 500 mg q8h. In very sick patients, colectomy may be necessary and can be life-saving.
- In terms of vancomycin, I only give it orally. I never give it IV because IV doesn’t work to treat CDI.
- Probiotics require further study, and are not recommended as standard-of-care. They may be considered as an adjunct to CDI treatment in patients with recurrent disease that is not severe, as long as there are no significant comorbidities.
One more thing for patients in British Columbia: Oral vancomycin is very expensive. Filling out a special authority form for Pharmacare allows eligible patients to qualify for coverage. These forms are available online at www.health.gov.bc.ca/exforms/pharmacare/5328fil.pdf.
Once the CDI treatment is completed, if the patient feels well, I do not re-test them for C. difficile, and I do not test their family members for asymptomatic carriage. The reason is that patients may continue to have C. difficile in their stool, but as long as it’s not causing them symptoms, treatment is not necessary.
To prevent recurrence of CDI, I tell patients to avoid antibiotics unless absolutely necessary. They should also avoid anti-secretory therapy (PPIs) if possible (see Dr. Ted Steiner’s post, thischangedmypractice.com/ppis-and-c-difficile-infection July 4, 2011).
Clinical Practice Guidelines for Clostridium difficile Infection in Adults: 2010 Update by the Society for Healthcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA). Stuart H. Cohen, Dale N. Gerding, Studart Johnson et al. Infection Control and Hospital Epidemiology, Vol. 31, No. 5 (May 2010), pp. 431-455. http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/cdiff2010a.pdf