Group A -Hemolytic Streptococcal Osteomyelitis in Children

Objective Little attention has been given to acute hematogenous osteomyelitis (AHO) caused by group A -hemolytic Streptococcus (GABHS), although up to 10% of cases are caused by this microorganism. The objective of this study was to define the clinical and laboratory characteristics of AHO caused by GABHS. Methods. Between January 1983 and June 1999, 29 patients were treated at Children’s National Medical Center with AHO caused by GABHS. The characteristics of these patients were compared with those of 28 patients with AHO caused by Streptococcus pneumoniae and those of a matched sample of 45 patients with AHO caused by Staphylococcus aureus. Results. Median ages of children with GABHS, S pneumoniae, and S aureus AHO were 36.0, 13.7, and 96.0 months, respectively. On admission, patients with GABHS AHO had a mean temperature of 38.9 1.3°C and a mean white blood cell count of 17 000 7800/mm3, findings similar to those from patients with S pneumoniae AHO. Patients with S aureus AHO had significantly lower admission temperature (38.1 1.1°C) and white blood cell count (10 600 4900/mm3). Varicella infection was the risk factor in 5 cases (17%) of GABHS AHO, whereas none of the cases of AHO caused by S pneumoniae and S aureus was associated with varicella infection. Adjacent septic arthritis occurred in 22%, 28%, and 61% of children with GABHS, S aureus, and S pneumoniae AHO, respectively. Admission erythrocyte sedimentation rate and frequency of bacteremia were similar in all groups. However, time to normalization of erythrocyte sedimentation rate was longer for GABHS and S aureus than for S pneumoniae AHO. GABHS, like S pneumoniae, affected fewer nonextremity bones compared with S aureus. Conclusions. GABHS should be considered in preschooland early school-aged children who are suspected of having AHO and whose clinical and laboratory features are characterized by high fever and marked leukocytosis. It should also be highly considered in any child with AHO associated with varicella infection. Pediatrics 2003;112:e22–e26. URL: http://www.pediatrics.org/cgi/ content/full/112/1/e22; acute hematogenous osteomyelitis, group A -hemolytic streptococcus, varicella. ABBREVIATIONS. AHO, acute hematogenous osteomyelitis; GABHS, group A -hemolytic Streptococcus; WBC, white blood cell; ESR, erythrocyte sedimentation rate. Although acute hematogenous osteomyelitis (AHO) seems to have become less prevalent in industrialized countries,1 the diagnosis and management of AHO continue to challenge clinicians who care for children with this infection.2 Staphylococcus aureus is the predominant cause of AHO (40%–80% of cases),3–5 and group A -hemolytic Streptococcus (GABHS) is the next in frequency.2,3 Other organisms, including Streptococcus pneumoniae, Haemophilus influenzae type b, and Kingella kingae, are less frequently associated with AHO.2 In the United States, the widespread use of conjugate vaccine against H influenzae since the late 1980s has virtually eliminated AHO caused by this organism.6 In addition, the recent approval by the Food and Drug Administration of a new 7-valent conjugate vaccine against S pneumoniae should have a significant impact on the incidence of invasive diseases caused by this bacterium.7 Despite numerous studies pertaining to AHO, many important aspects of this infection remain to be elucidated fully. In fact, the majority of studies of AHO analyzed all cases as a group but not according to the causative agent.1,5,6,8 Because S aureus is the most frequent causative agent, published data have emphasized the characteristics of S aureus AHO with apparent marginalization of other less frequent causative microorganisms. Scattered reports in the literature have focused on AHO caused by specific organisms such as H influenzae4,9 and S pneumoniae.10,11 However, to the best of our knowledge, no published studies have addressed the characteristics of AHO caused by GABHS, the second most common causative agent of AHO in children. In this article, we provide information on the clinical and laboratory characteristics of childhood AHO caused by GABHS and compare these characteristics with those of AHO caused by S aureus and S pneumoniae.