Background: Staphylococcus aureus is the most common cause of acute hematogenous osteoarticular infections (AHOAIs) in children. While the vast majority of patients do well, a small proportion experience significant morbidity including chronic infection and pathologic fractures. We sought to describe clinical and microbiologic variables present on the index admission which may predict long term orthopedic complications (OC).
Methods: Cases of S. aureus AHOAI were identified from 2011-2016 at Texas Childrens Hospital (TCH). All cases were reviewed for the development of OC until April 1, 2018. OC included chronic osteomyelitis (CO), growth arrest/limb length discrepancy, avascular necrosis, chronic dislocation and pathologic fracture (PF) with or without angular deformity. All S. aureus isolates were characterized by PCR for Panton-Valentine Leukocidin (PVL) genes and agr group. Statistical Analyses were performed with STATA.
Results: 252 cases were identified meeting inclusion criteria (Figure). 24 (9.5%) developed OC of which 50% were CO and 25% PF. Patients who developed CO more often had positive blood cultures during the index admission (p<0.001), surgical drainage after hospital day 2 (33.3% vs. 8.8%, p=0.02) as well as a longer time to 50% reduction in C-reactive protein (CRP, 9 vs. 7 days, p=0.01). Patients who developed PF more often had infection due to PVL-positive organisms (83.3% vs. 38.6%, p=0.03) and had a longer duration of fever after admission (9.5 vs. 2.5 days, p=0.03). Overall, OC were associated with ICU admission (p=0.04), a slower decline in CRP (p=0.02) and a greater proportion of patients with surgery after hospital day 2 (p=0.04) as well as infection secondary to agr III isolates (p=0.03). There was no statistically significant relationship between OC and patient age, affected bone, time to initiation of effective antimicrobial therapy, duration of intravenous therapy or final antibiotic choice.
Conclusion: Patients with S. aureus AHOAI with a delay in source control, slow decline in CRP, prolonged fever or ICU admission are at higher risk of OC. While nonspecific, these findings suggest that such patients may warrant especially cautious clinical follow up to identify sequelae early. Large multicenter studies are needed to better predict OC in this setting.
J. C. McNeil,
L. Sommer, None
J. G. Vallejo, None
K. G. Hulten, None
S. L. Kaplan, None
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