Which condition is characterized by acute onset of fever, joint pain, and refusal to bear weight?

The condition characterized by the acute onset of fever, joint pain, and refusal to bear weight is septic arthritis. This condition is a result of infection in the joint, most commonly caused by bacteria, which leads to rapid inflammation and pain. The fever indicates a systemic response to the infection, while the joint pain and refusal to bear weight reflect the localized impact on the affected joint(s). In pediatric patients, prompt recognition is critical as septic arthritis can lead to severe joint damage if not treated quickly.

In contrast, rheumatoid arthritis and juvenile idiopathic arthritis usually have a more insidious onset and are generally associated with prolonged symptoms rather than an acute fever. Osteomyelitis, while it may present with fever and localized pain, usually involves pain in the bone rather than the joint specifically, and can also have a different clinical presentation compared to septic arthritis.