Native joint arthritis in children

Bacterial and fungal joint infections in children are medical emergencies. Septic arthritis is more common in childhood than in any other period, and more than half of cases are diagnosed in individuals younger than 20 years of age. Because joint infections in children usually result from hematogenous seeding, the etiology of septic arthritis frequently overlaps that of pediatric bacteremia. Some microorganisms such as Staphylococcus aureus or K. kingae are remarkably overrepresented in childhood arthritis, indicating joint tissue tropism. Pediatric septic arthritis may also result from direct inoculation of organisms in the joint by a human or animal bite, joint taps especially with the injection of corticosteroids, or surgical procedures. The key to the diagnosis of bacterial arthritis in children is a high index of clinical suspicion. The differential diagnosis of septic arthritis is wide and depends on the patient's age, underlying clinical conditions, and the joint involved.