A 2-year-old Caucasian girl has had left knee swelling for 2 months (Figure 172-1). On physical examination, she has a warm left knee with limited range of motion and an effusion. Her left leg is longer than her right, and she walks with an antalgic gait. She has no other systemic signs and symptoms. Her antinuclear antigen (ANA) test is positive (1:160, speckled pattern) and her erythrocyte sedimentation rate is normal. She is diagnosed with oligoarticular juvenile idiopathic arthritis (oligoJIA). After initially taking nonsteroidal antiinflammatory medication around the clock, she is given an intra-articular steroid injection to treat her synovitis followed by physical therapy. Six weeks later, her knee exhibits full range of motion and is free of swelling. Six months later, she is found to have anterior uveitis (Figure 172-2) on routine screening slit lamp ophthalmology exam. Her uveitis is treated with ocular steroid drops, but her eye disease remains active, and requires the disease modifying antirheumatic drug, methotrexate.
Swelling of the left knee in a 2-year-old girl with oligoarticular JIA. (Used with permission from Vidya Raman, MD.)
Synechiae complicating anterior nongranulomatous uveitis in a child with juvenile idiopathic arthritis. (Used with permission from Carol A. Wallace, MD.)
Juvenile Idiopathic Arthritis (JIA), the most common chronic rheumatologic disease of childhood,1 is defined by arthritis lasting greater than 6 weeks clinically beginning in a child before their 16th birthday after infection or other systemic etiologies have been ruled out. JIA is divided into 7 phenotypic subtypes which include: oligoarticular (persistent, extended), polyarticular (rheumatoid factor [RF] positive), polyarticular (RF negative), systemic onset, psoriatic, enthesitis related, and undifferentiated.2
Juvenile chronic arthritis (JCA) and juvenile rheumatoid arthritis (JRA).
JIA occurs worldwide.
The prevalence is ~1 per 1,000 children, and the incidence is ~12 new cases per 100,000 children.3
JIA appears to occur more commonly in children of Northern European ancestry.
A striking age of onset peak in the oligoarticular type is noted between 1 to 2 years of age, in contrast to polyarticular JIA, which has a biphasic clinical onset with one peak between 1 to 3 years of age and another late in school age and into adolescence. Systemic onset JIA is more common in toddler-aged children, but otherwise onset is rather equally distributed amongst ages.
In general, girls are affected more often than boys, but gender distribution varies with disease subtypes. The most common subtype, oligoJIA, occurs most commonly in toddler-aged girls (F: M, 3:1) and accounts for close to half of JIA diagnoses.
Anterior nongranulomatous uveitis occurs in ~15 percent of ANA-positive ...