My patient has a sacral decubitus ulcer that can be probed to the bone. Should I assume she has osteomyelitis?

When dealing with pressure sores, there is no definitive way of making a diagnosis of osteomyelitis short of a biopsy of the involved bone1.  In fact, only about a third of stage IV pressure ulcers (those extending to the bone) may be associated with osteomyelitis2. In a study of pressure sores related to spinal cord injury or cerebrovascular accident, the clinical judgement of physicians with respect to the presence of osteomyelitis was accurate in only 56% of patients.  Only 3 of 21 patients with exposed bone had a diagnosis of osteomyelitis confirmed on biopsy3.

The “Probe to the Bone” bedside procedure has been studied primarily in diabetic foot infections with a recent systematic review reporting pooled sensitivity and specificity of 0.87 (95% confidence interval [CI], .75-.93) and 0.83 (95% CI, .65-.93), respectively4. Its performance in non-diabetic patients or those without a foot infection needs further study.

So in our patient, we should not assume a diagnosis of osteomyelitis; a bone biopsy is necessary for a definitive diagnosis.

References

  1. Larson DL, Gilstrap J, Simonelic K, et al. Is there a simple, definitive, and cost-effective way to diagnose osteomyelitis in the pressure ulcer patient? Plast Reconstr Surg 2011; 127:67
  2. Bodavula P, Liang SY, Wu J et al. Pressure ulcer-related pelvic osteomyelitis: a neglected disease? Open Forum Infect Dis 2015. DOI:10.1093/ofid/ofv112.
  3. Darouiche RO, Landon GC, Klima M et al. Osteomyelitis associated with pressure sores. Arch Intern Med 1994;154:753-58.
  4. Lam K, van Asten SA, Nguyen T, et al. Diagnostic accuracy of probe to bone to detect osteomyelitis in the diabetic foot: a systematic review. Clin Infect Dis 2016;63:944-8.
My patient has a sacral decubitus ulcer that can be probed to the bone. Should I assume she has osteomyelitis?

My patient with foot osteomyelitis due to methicillin-sensitive Staphylococcus aureus (MSSA) is ready to go home on IV antibiotic therapy. Is daily ceftriaxone therapy an appropriate option?

Yes, it is!  Ceftriaxone has excellent activity against MSSA .  In a retrospective study comparing ceftriaxone to oxacillin for osteoarticular infections due to MSSA, there was no difference in treatment success at 3-6 and > 6 months following completion of IV antibiotics; oxacillin had to be discontinued more often due to toxicity, however (1).    In another retrospective study comparing cefazolin to ceftriaxone for treatment of MSSA infections ( ≥50% of patients with osteomyelitis),  favorable outcomes, adverse events and complications were similar between the 2 groups (2). 

1. Wieland BW, Marcantoni JR, Bommarito KM, et al. A retrospective comparison of ceftriaxone versus oxacillin for osteoarticular infections due to methicillin-susceptible Staphylococcus aureus. Clin Infect Dis 2012;54:585-590

2.  Winans SA, Luce Am, Hasbun R. Outpatient parenteral antimicrobial therapy for the treatment of methicillin-susceptible Staphylococcus aureus: a comparison of cefazolin and ceftriaxone. Infection 2103;41:769-774.

My patient with foot osteomyelitis due to methicillin-sensitive Staphylococcus aureus (MSSA) is ready to go home on IV antibiotic therapy. Is daily ceftriaxone therapy an appropriate option?