American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment alternative may be considered if Fidaxomicin or Metronidazole was used in the first episode of non-fulminant C. diff?

1. Increased dosage of the same medication

2. Vancomycin 125 mg orally four times daily

3. Complete rest and hydration

4. Immediate surgery

The correct answer is: Vancomycin 125 mg orally four times daily

In the management of non-fulminant Clostridioides difficile infection (CDI), if the initial treatment with either Fidaxomicin or Metronidazole has been unsuccessful or if there is a recurrence, Vancomycin is a key alternative. The choice of Vancomycin 125 mg orally four times daily is particularly relevant because it is considered a first-line treatment for CDI. This dosing regimen has demonstrated effectiveness in treating subsequent episodes of CDI, particularly in patients who have had a previous recurrence after the initial treatment. Treating recurrent CDI with Vancomycin not only addresses the infection effectively but also provides a different antibiotic mechanism compared to Fidaxomicin and Metronidazole, which may have already been used. This approach helps to minimize the risk of antibiotic resistance and potential side effects associated with repeated cycles of the same medication. Options such as increasing the dosage of the same medication may not provide the desired therapeutic effect, as the recurrence indicates that the initial treatment was inadequate. Complete rest and hydration are important supportive measures in the recovery of any infection but do not address the underlying cause, and therefore, are insufficient as standalone treatments. Immediate surgery is reserved for severe cases or complications such as toxic megacolon or