The impact of the current epidemiology of pediatric musculoskeletal infection on evaluation and treatment guidelines.

BACKGROUND: Methicillin-resistant Staphylococcus aureus is thought to have led to an increase in the incidence of severe musculoskeletal infection in children. Our purpose was (1) to compare the current epidemiology of musculoskeletal infection with historical data at the same institution 20 years prior and (2) to evaluate the spectrum of the severity of this disease process within the current epidemiology.

METHODS: Children with musculoskeletal infection, treated between January 2002 and December 2004, were studied retrospectively. Diagnoses of osteomyelitis, septic arthritis, pyomyositis, and abscess were established for each child based on overall clinical impression, laboratory indices, culture results, radiology studies, and intraoperative findings. Comparison was made with the experience reported at the same institution in 1982. Children within each diagnostic category were compared with respect to mean values of C-reactive protein and erythrocyte sedimentation rate at admission, number of surgical procedures, intensive care unit admissions, identification of deep venous thrombosis, and length of hospitalization.

RESULTS: Five hundred fifty-four children were studied (osteomyelitis, n = 212; septic arthritis, n = 118; pyomyositis, n = 20; and deep abscess, n = 204). The annualized per capita incidence of osteomyelitis increased 2.8-fold, whereas that of septic arthritis was unchanged when compared with historical data from 20 years prior. Methicillin-resistant Staphylococcus aureus was isolated as the causative organism in 30% of the children. We identified increasing severity of illness according to a hierarchy of tissue involvement (osteomyelitis > septic arthritis > pyomyositis > abscess) and according to the identification of contiguous infections within in each primary diagnostic category.

CONCLUSIONS: The incidence of musculoskeletal infection appears to have increased within our community. We found that a more comprehensive diagnostic classification of this disease is useful in understanding the spectrum of the severity of illness and identifying those who require the greatest amount of resources. Magnetic resonance imaging is useful early in the diagnostic process to enable a more detailed disease classification and to expedite surgical decisions. The recognition of the incidence of methicillin-resistant Staphylococcus aureus within our community has also led to a change in empirical antibiotic selection.