Chapter 81. Osteomyelitis
Case pertaining to questions 1–6:
An 82-year-old woman with no known allergies was admitted to the hospital to receive surgical and medical management for suspected osteomyelitis of the tibia. During surgical debridement, a bone biopsy was obtained for culture and histopathology. The microbiology laboratory reported Staphylococcus aureus, susceptible to vancomycin, linezolid, daptomycin, trimethoprim-sulfamethoxazole but resistant to penicillin, oxacillin, ciprofloxacin, erythromycin, and clindamycin.
Select an appropriate intravenous antimicrobial regimen for this patient.
Option A: Incorrect. Linezolid can be used for osteomyelitis, but given the common treatment duration is not optimal due to adverse effects.
Option B: Incorrect. The organism cultured is resistant to oxacillin and should be considered resistant to nafcillin as well.
Option C: Incorrect. Even though it is susceptible, use of trimethoprim-sulfamethoxazole is usually used as an oral option and is not considered to be an appropriate initial therapy in most cases.
Option D: Correct. Vancomycin is widely considered the first-line therapy for MRSA infections including osteomyelitis.
Which laboratory parameter(s) should be monitored weekly in this patient receiving intravenous antibiotic therapy?
Option A: Incorrect. Liver function tests are not considered to be routinely needed in patients receiving intravenous antimicrobial therapy. This is also dependent on the antimicrobial regimen selected.
Option B: Correct. BUN/SCr should be routinely be monitored in most regimens which include an agent with renal clearance.
Option C: Incorrect. Eosinophils are not routinely monitored in patients receiving intravenous antibiotics.
Option D: Incorrect. Eosinophils are not frequently monitored unless the possibility of allergy arises.
Response to therapy can be evaluated by the following laboratory test(s):
Option A: Incorrect. CPK is monitored with daptomycin therapy, but is not associated with response to therapy.
Option B: Incorrect. CRP is an inflammatory marker which can be followed to assess response to therapy ...