Juvenile Idiopathic Arthritis (JIA)

Basic Information

  1. ▪JIA is a chronic autoimmune condition affecting the joints and eyes
  2. ▪By definition, age of onset is <16 years, and symptoms of arthritis must be present for at least 6 weeks
  3. ▪Untreated arthritis leads to joint contractures and permanent joint damage
  4. ▪Untreated uveitis (eye inflammation) leads to blindness
  5. ▪There are six subtypes with varying prognosis and clinical manifestations:
    • ▪Oligoarticular JIA
    • ▪Polyarticular JIA with negative rheumatoid factor (RF)
    • ▪Polyarticular JIA with positive RF
    • ▪Psoriatic JIA
    • ▪Enthesitis-related JIA
    • ▪Systemic-onset JIA

Clinical Presentation

  1. ▪In all subtypes, stiffness and joint swelling are more prominent than joint pain
    1. ▪Decreased range of motion progresses over time
    2. ▪Leg length discrepancies or even growth retardation can result from chronic lower-extremity arthritis
    3. ▪Micrognathia and jaw asymmetry can result from temporomandibular joint arthritis

Oligoarticular JIA

Most commonly occurs in toddler-age (3 years old) Caucasian females

Four or more joints are involved initially

Large joints, knee > ankle > wrist (but almost never hip or shoulder)

Insidious onset

Frequently antinuclear antibody (ANA) positive → highest risk of uveitis

Uveitis is usually asymptomatic; therefore all patients require regular ophthalmologic screening

Polyarticular JIA

Bimodal peak at age 1 to 3 years, and then adolescence, with female predominance

More than five joints are involved

Symmetrically involves small joints of hands and feet, in addition to large joints

RF positivity confers a worse prognosis:

Similar to adult rheumatoid arthritis; subcutaneous rheumatoid nodules may be present

Asymptomatic uveitis is less common than in oligoarticular JIA

Psoriatic JIA

Arthritis and psoriasis or other features that overlap with psoriasis:

Dactylitis (“sausage digits”), nail pits or onycholysis, family history of psoriasis

Asymmetrically involves small joints (especially distal interphalangeal [DIP]) and large joints

Asymptomatic uveitis (especially if ANA positive)

Enthesitis-related JIA/juvenile ankylosing spondylitis

  • ▪Frequently HLA-B27 positive, and more common in adolescent boys
  • ▪Family history of other HLA-B27-positive spondyloarthropathies (ankylosing spondylitis, sacroiliitis with inflammatory bowel disease, reactive arthritis)
  • ▪Peripheral arthritis, enthesitis, or axial involvement:
    1. ▪Inflammatory back pain is associated with sacroiliitis
      • ▪Back stiffness that is worse in the morning or with prolonged sitting and that improves with activity
        1. □Difficulty with forward flexion and flattening of the natural lumbar lordosis
        2. □Tenderness over the sacroiliac joints
    2. ▪Enthesitis is tenderness at insertion sites of tendons/ligaments into bone
    3. ▪Enthesitis-related JIA can progress to ankylosing spondylitis in adult years (fusion of lumbar vertebrae results in the classic “bamboo spine” radiographic finding)
  • ▪Uveitis presents as an acute, painful red eye rather than asymptomatic uveitis
  • ▪Significant overlap with inflammatory bowel disease–associated arthropathies, so close monitoring for gastrointestinal symptoms is necessary

Systemic-onset JIA

Previously known as Still disease, it is a completely separate disease from other JIA subtypes

Characterized by severe autoinflammation with peak onset at 1 to 5 years old:

High-spiking fevers for at least 2 weeks, classically in a quotidian (daily) pattern

Evanescent salmon-colored macules appear in conjunction with fever

May appear in linear streaks or look urticarial with surrounding pallor

Lymphadenopathy and hepatosplenomegaly

Serositis (pleural/pericardial effusions, ascites)

Polyarticular arthritis (especially hip and cervical spine)

Not associated with a risk of uveitis

Frequently complicated by macrophage activation syndrome (MAS), also known as secondary hemophagocytic lymphohistiocytosis, which is a severe, life-threatening state of dysregulated systemic inflammation and organ failure

Diagnosis and Evaluation

Laboratory testing can help characterize the type of JIA but is not used to make a diagnosis of JIA:

ANA determines risk of uveitis

A positive ANA at low titers (1:160) can be detected in up to 20% of healthy children, and therefore it is not useful for diagnosis

RF and HLA-B27 help determine JIA subtype

Lyme should be excluded as a cause of chronic arthritis

A mild leukocytosis, thrombocytosis, normocytic anemia, and mildly elevated ESR/CRP may be associated with active oligoarticular or polyarticular JIA

In contrast, systemic-onset JIA is characterized by prominent leukocytosis, thrombocytosis, anemia, and elevated acute-phase reactants, especially ferritin

± Transaminitis, hypoalbuminemia, prolonged coagulation time

Cytopenias and dropping ESR (from fibrinogen consumption) in the setting of rising ferritin levels are indicators of MAS

Synovial fluid analysis confirms that the effusion is inflammatory (WBC 5,000–20,000; up to 100,000 in systemic-onset JIA)

Ultrasound can be used to demonstrate joint effusions if clinical examination is equivocal

Demonstration of uveitis on slit-lamp examination can substantiate the diagnosis


All children suspected of having JIA should be referred to a rheumatologist

Those diagnosed with JIA require ophthalmologic screening at regular intervals

Mono- or oligoarticular arthritis is usually amenable to intraarticular corticosteroid injections

Immunosuppressants such as low-dose methotrexate are usually needed for polyarticular arthritis

NSAIDs can be helpful for pain and very mild arthritis

Systemic-onset JIA is treated with systemic corticosteroids in combination with other antiinflammatory medications

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