A Systematic Approach to the Evaluation of a Limping Child.

A limp is defined as a deviation from a normal age-appropriate gait pattern resulting in an uneven, jerky, or laborious gait. It can be caused by pain, weakness, or deformity as a result of a variety of conditions. Transient synovitis is the most common diagnosis. Other causes of acute limp include contusion, foreign body in the foot, fracture, osteomyelitis, septic arthritis, reactive arthritis, and Lyme arthritis. Causes of chronic limp include rheumatic disease, dermatomyositis, acute rheumatic fever, inflammatory bowel disease, and systemic lupus erythematosus. Evaluation of a limping child should begin with a history focused on identifying pain, trauma, and associated systemic symptoms. For a limping child with focal findings on physical examination, initial imaging includes anteroposterior and lateral radiography of the involved site. If there are no focal findings on physical examination, radiography of both lower extremities should be performed. Laboratory testing is guided by history and physical examination findings. Septic arthritis of the hip should be suspected in a child with an oral temperature more than 101.3°F (38.5°C), refusal to bear weight, erythrocyte sedimentation rate more than 40 mm per hour, peripheral white blood cell count more than 12,000 per mm3 (12 × 109 per L), or C-reactive protein level more than 20 mg per L (180.96 nmol per L).