Introduction Kingella kingae is increasingly being recognised as a common aetiology of osteoarticular infections, especially in younger children. Infections are usually mild with a favourable outcome. However, unusually complicated cases have been rarely reported.
Case Report Three children with complicated K. kingae osteoarticular infection were identified. The age varied between 2 to 3 years-old and the diagnostic delay was 12 ± 6 days. All had lower limb claudication, low grade fever and normal-to-mild elevated acute-phase reactants. Radiologic exams showed unifocal bone lytic lesions compatible with abscess (astragalus, calcaneus and external malleolus). Cultures of bone exudate or joint fluid identified Kingella kingae. Osseous lytic lesions were drained in all cases and joint fluid was aspirated in one. Antibiotherapy with cephalosporins or amoxicillin-clavulanate was done: intravenous for 8 ± 2 days, followed by oral treatment for 26 ± 5 days (total duration 34 ± 6 days). There was complete clinical recovery at 3 month, with disappearance of the osteolytic lesions in two patients.
Conclusions In these cases several characteristics of Kingella kingae infections are identified, as young age, mild clinical presentation, normal-to-mild elevated inflammatory markers, single focus and favourable response to antibiotics. Although K. kingae bone lytic lesions are rarely identified they could led to important sequels and should be vigorously treated.