What is the workup and treatment for juvenile arthritis?

Workup and Treatment for Juvenile Idiopathic Arthritis

Begin with DMARD therapy (methotrexate) as first-line treatment for polyarticular JIA, escalating to biologics if inadequate response after 3 months, while NSAIDs and intraarticular glucocorticoids serve as adjunctive therapy. 1

Diagnostic Workup

Clinical Assessment

• Confirm arthritis duration ≥6 weeks in children <16 years of age to meet JIA diagnostic criteria 1
• Document number of joints involved in first 6 months to determine subtype classification 1
• Assess for extraarticular manifestations including fever, rash, enthesitis, and inflammatory back pain 1
• Perform ophthalmologic examination to screen for uveitis, particularly in oligoarticular JIA with ANA positivity 2

Laboratory Evaluation

• Obtain rheumatoid factor (RF), anti-CCP antibodies, and ANA to identify risk factors for aggressive disease 1
• Test for HLA-B27 in patients with suspected enthesitis-related arthritis or sacroiliitis 1
• Baseline CBC, liver function tests, and creatinine are required before initiating therapy 3
• Exclude other diagnoses: systemic lupus erythematosus, rheumatic fever, infection, malignancy 1, 4

Imaging Studies

• Plain radiographs establish baseline joint damage but lack sensitivity for early inflammatory changes 5
• MRI or ultrasound are more sensitive than clinical examination for detecting synovitis and should be considered when diagnosis is uncertain 5
• MRI with contrast is recommended to confirm active sacroiliitis when clinically suspected 1

Treatment Algorithm

Initial Therapy for Polyarticular JIA (≥5 joints)

For patients WITHOUT risk factors (RF-, anti-CCP-, no joint damage):

• Start methotrexate as first-line DMARD over biologic therapy 1, 6
• Subcutaneous methotrexate is preferred over oral formulation for better bioavailability 1
• Typical dosing: 10-15 mg/m² weekly, maximum 25 mg weekly 2
• Add NSAIDs as adjunctive therapy for symptom control 1
• Intraarticular triamcinolone hexacetonide (strongly preferred over triamcinolone acetonide) for accessible joints 1
• Consider bridging with oral glucocorticoids <3 months if moderate/high disease activity (cJADAS-10 >2.5) 1

For patients WITH risk factors (RF+, anti-CCP+, or joint damage):

• Still initiate DMARD therapy first in most cases 1
• However, initial biologic therapy may be appropriate for patients with high-risk joint involvement (wrist, hip, cervical spine), very high disease activity, or physician assessment of high risk for disabling damage 1

Escalation Strategy for Inadequate Response

Define adequate trial: 3 months of methotrexate, though escalation at 6-8 weeks is reasonable if minimal/no response 1, 6

For patients with moderate/high disease activity (cJADAS-10 >2.5):

• Add biologic DMARD to methotrexate rather than switching to second DMARD or triple DMARD therapy 1
• First-line biologics: TNF inhibitors (etanercept, adalimumab, infliximab), abatacept, or tocilizumab 1, 3
• Tocilizumab is FDA-approved for polyarticular JIA in patients ≥2 years 3

For patients with low disease activity (cJADAS-10 ≤2.5 with ≥1 active joint):

• Escalate therapy to achieve complete disease control 1, 6
• Options include: optimizing DMARD dose, adding intraarticular glucocorticoids, or adding biologic 1

For biologic failure:

• After primary TNF inhibitor failure, switching to non-TNF biologic (abatacept, tocilizumab) is preferred over second TNF inhibitor 1
• Alternative options include rituximab for refractory cases 1

Initial Therapy for Oligoarticular JIA (1-4 joints)

• Trial of scheduled NSAIDs as part of initial therapy 6
• Intraarticular glucocorticoid injections strongly recommended as initial therapy 6
• Oral glucocorticoids are NOT recommended for initial therapy 6
• If inadequate response to NSAIDs/IAGCs: start methotrexate as preferred csDMARD 6
• If inadequate response to ≥1 csDMARD: add biologic DMARD 6

Systemic JIA Management

• NSAIDs conditionally recommended as initial monotherapy 6
• IL-1 inhibitors (anakinra, canakinumab) or IL-6 inhibitors (tocilizumab) strongly recommended over conventional DMARDs for inadequate response to NSAIDs/glucocorticoids 6, 2
• Conventional DMARDs are NOT recommended as initial monotherapy 6
• For residual arthritis despite IL-1/IL-6 inhibition, biologics or csDMARDs are preferred over long-term glucocorticoids 6

Enthesitis-Related Arthritis and Sacroiliitis

• NSAIDs as initial therapy for active enthesitis 1
• TNF inhibitors are first-line biologics for inadequate NSAID response 1, 2
• Sulfasalazine may be considered for peripheral arthritis 2
• Physical therapy is essential adjunctive treatment 1

Critical Monitoring Parameters

Laboratory Monitoring on Methotrexate

• CBC and liver function tests every 2-4 weeks initially, then every 8-12 weeks once stable 3
• Do not initiate if ANC <2000/mm³, platelets <100,000/mm³, or ALT/AST >1.5× ULN 3

Infection Screening Before Biologics

• Test for latent tuberculosis (tuberculin skin test or interferon-gamma release assay) before initiating biologics 3
• Treat latent TB before starting biologic therapy 3
• Screen for hepatitis B and C 3

Disease Activity Assessment

• Use validated measures (cJADAS-10) to guide treat-to-target approach 1, 6
• Target: low disease activity (cJADAS-10 ≤2.5) or inactive disease 1

Critical Pitfalls to Avoid

• Never use chronic low-dose oral glucocorticoids regardless of disease activity—strongly contraindicated due to growth suppression and osteoporosis 1
• Do not delay DMARD initiation in polyarticular disease—early aggressive treatment prevents permanent joint damage 1, 2
• Do not combine multiple biologic DMARDs due to excessive immunosuppression risk 3
• Do not miss uveitis screening—particularly critical in young girls with oligoarticular JIA and ANA positivity 2
• Recognize macrophage activation syndrome in systemic JIA—life-threatening complication requiring immediate intervention 2, 7

Adjunctive Therapies

• Physical and occupational therapy strongly recommended throughout disease course 1
• Multidisciplinary team including pediatric rheumatologist, ophthalmologist, orthopedist, and physiotherapist 2
• Shared decision-making with patients and caregivers regarding treatment choices 1