Snapshot A 9-year-old girl presents to his pediatrican's office by his mother due to fever and joint pain. The mother reports that she has been having knee and wrist pain for approximately 7 weeks. Her pain is worse in the morning and is associated with swelling of the affected joint. She develops a fever daily that later subsides. On physical exam, there is tenderness to palpation of the affected joint. Laboratory studies are significant for an elevated ANA, ESR, and CRP. She is negative for rheumatoid factor. Introduction Clinical definition a broad term that encompasses different types of pediatric chronic arthritis that is characterized by joint pain and inflammation 1 or more joints are involved for at least 6 weeks in patients < 16 years of age subtypes polyarticular juvenile idiopathic arthritis (JIA) ≥ 5 joints involved pauciarticular JIA 1-4 joints involved systemic JIA visceral involvement Epidemiology incidence the most common chronic rheumatologic disorder in children demographics more frequently with European ancestry Pathogenesis not well understood but may involve both genetic and environmental factors the humoral and cell-mediated immune system are involved T-cells release tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1 the humoral immune system is involved by increasing antinuclear antibody (ANA) production, immunoglobulins, and circulating immune complexes Prognosis postitive improved with advances in treatment negative early hip or wrist involvement presence of rheumatoid factor Presentation Symptoms fever quotidian pattern fevers occurring once or twice per day that eventually subside morning stiffness and joint pain joint stiffness and pain can also be noted with prolonged periods of inactivity (e.g., sitting) visual changes can be suggestive of a uveitis Physical exam joint involvement swelling limited range of motion tenderness to palpation uveitis visceral involvement in cases of systemic JIA such as evanescent and salmon-colored macular rash hepatosplenomegaly serositis e.g., pleural and pericardial effusion Studies Labs ↑ c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) typically in systemic and polyarticular JIA positive ANA in most cases Diagnostic criteria a patient < 16 years of age with 1 or more joints involved for at least 6 weeks Differential Reactive arthritis Rheumatoid arthritis Systemic lupus erythematosus Leukemia Pediatric sarcoidosis Treatment Conservative period ophthalmologic exams indication for monitoring of eye involvement (e.g., uveitis) Medical nonsteroidal antiinflammatory drugs (NSAIDs) indication for symptomatic relief disease-modifying antirheumatic drugs (DMARDs) indication for controlling inflammatory process medication methotrexate etanercept adalimumab intra-articular glucocorticoids indication effective in managing inflamed joint Complications Infection Macrophage-activation syndrome Pericarditis Hemolytic anemia Enarteritis