Juvenile rheumatoid arthritis

CASE: A mother of a 2-year-old girl brings her daughter to a pediatrician for a third opinion. For the past five weeks, the girl has been feeling “not quite herself in the morning.” She has been irritable and slow to get out of bed, sometimes refusing to get up altogether, and walks more stiffly than usual. She gets better as the day goes on but worsens again after her afternoon nap, and seems especially uncomfortable when her diaper is being changed. Two weeks after the onset of symptoms, the mother consulted with the child’s family doctor, who surmised the cause to be either normal growing pains or a bad fall on the knee. He referred the girl to an orthopedic surgeon, who failed to detect any evidence of a fall and referred the child to the pediatrician in question. EPIDEMIOLOGY AND CLINICAL PRESENTATION ‘Juvenile arthritis’ (JA), encompasses the spondyloarthropathies and reactive arthritis. Juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA), comprises three distinct presentations, the most common of which is early-onset pauciarticular disease seen most frequently in girls, as in the above case. By definition, one of the criteria for JRA requires the exclusion of other forms of JA. Estimates for the overall prevalence of JRA in children under 16 cluster around the 0.01% mark. JRA is subdivided into three types with distinct presentations and courses: • Pauciarticular JRA (paJRA, four or fewer joints involved) accounts for 50% of JRA cases. Juvenile rheumatoid arthritis