Juvenile Idiopathic Arthritis
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Introduction
Juvenile Idiopathic Arthritis (JIA), also known as Juvenile Rheumatoid Arthritis, is a family of conditions characterized by persistent arthritis in children under age 16.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
Pathophysiology
Signs and Symptoms
JIA is diagnosed as arthritis one or more joints lasting >6 weeks in a child <16 years of age, excluding other causes of arthritis.
- history
- classification
- physical exam
History
Classification
JIA is classified according to the features and numbers of joints affected, during the first 6 months:
- systemic: arthritis, fever, and other constitutional symptoms
- polyarticular: 5 or more joints
- oligoarticular: 4 or less joints (most common)
- enthesitis-related arthritis
- psoriatic arthritis
- unclassified
Systemic (Still's Disease)
- high, spiking fever for at least two weeks
- salmon-coloured maculopapular rash
- lymphadenopathy
- hepatosplenomegaly
- leukocytosis, thrombocytosis
- anemia
- serositis
- high ESR, CRP
Oligoarticular arthritis
- persistent or extended
- typically large joints
- ANA positive in 80%, RF negative
- screen for asymptomatic anterior uveitis
Polyarticular
Physical Exam
Associated with uveitis
- acute uveitis, especially in enthesitis-related arthritis
- chronic, asymptomatic uveitis
- most common cause of acquired blindness in children in North America
Rash that comes and goes
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Differential Diagnosis
Juvenile idiopathic arthritis is a diagnosis of exclusion. Other possibilities which need to be ruled out include:
- infection
- reactive arthritis
- malignancy
- connective tissue disease
- mechanical conditions
- bleeding disorders
Treatments
Exercise is important to maintain strength and range of motion. Health care professionals involved include OT, PT, social work, orthopedics, opthalmology, rheumatology.
Medications
NSAIDs and intra-articular corticosteroids are first-line.
Second line:
- DMARDs - methotrexate, sulfasalazine
- systemic corticosteroids if warranted
- topical eye drops for uveitis
- biological agents: etanercept
Enthesitis-related JIA should be screened for uveitis approx. once yearly; oligo- and polyarticular more frequently.
Consequences and Course
Resources and References
Topic Development
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