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.  https://www.ncbi.nlm.nih.gov/pubmed/21285771
  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. https://www.ncbi.nlm.nih.gov/pubmed/26322317
  3. Darouiche RO, Landon GC, Klima M et al. Osteomyelitis associated with pressure sores. Arch Intern Med 1994;154:753-58. https://www.ncbi.nlm.nih.gov/pubmed/8147679
  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. https://www.ncbi.nlm.nih.gov/pubmed/27369321
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 appears to be!  Ceftriaxone is active against MSSA and may be an option for treatment of infections due to this organism at least in certain situations.  

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). 

Several other studies have reported no significant difference in treatment failure between cefazolin and ceftriaxone in MSSA infections (3).  A smaller retrospective study, however, reported higher rate of treatment failure (defined to include unplanned extension of parenteral therapy) with ceftriaxone in MSSA bacteremia without finding any difference in time to blood culture clearance, or rates of persistent bacteremia, relapse after treatment, achievement of source control, mortality or readmission (3).

References

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. https://www.ncbi.nlm.nih.gov/pubmed/22144536

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 2013;41:769-774. https://www.ncbi.nlm.nih.gov/pubmed/23686435

3. Carr DR, Stiefel U, Bonomo RA, etal. A comparison of cefazolin versus ceftriaxone for the treatment of methicillin-susceptible Staphylococcus aureus bacteremia in a tertiary care VA medical center. Open Forum Infectious Diseases, Volume 5, Issue 5, 1 may 2018, ofy089. https://academic.oup.com/ofid/article/5/5/ofy089/4999397

 

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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?