Juvenile Idiopathic Arthritis

What is JIA?

Chronic arthritis beginning before age 16, 1+ joint, and persisting >6 weeks. Can result in growth disturbances, joint contracture/destruction, chronic pain

What is the most common chronic rheumatologic disease of childhood?

Juvenile idiopathic arthritis (JIA)

What are the diagnostic criteria for JIA?

Age <16 years, arthritis >6 weeks, exclusion of other causes

Are there diagnostic laboratory tests for JIA?

No, JIA is a clinical diagnosis

What is arthralgia?

Joint pain without objective evidence of inflammation

What major diagnoses are in the differential for pediatric joint pain?

Trauma, biomechanical causes, infection(Lyme, Septic joint, Parvo), reactive causes(Acute Rheumatic Fever, Enteric), malignancy(leukemia, bone tumors), rheumatologic disease

What infections can mimic JIA?

Septic arthritis, osteomyelitis, Lyme disease, parvovirus, gonococcal infection

What malignancies should be considered in the differential of JIA?

Leukemia and bone tumors

What rheumatologic diseases can mimic JIA?

SLE, juvenile dermatomyositis, MCTD, vasculitis

How many categories of JIA exist?

Seven

What are the 7 categories of JIA?

Oligoarticular, Polyarticular RF-, Polyarticular RF+, Psoriatic, Enthesitis-related, Systemic, Undifferentiated

What defines Oligoarticular JIA? (Demographic, joint number, common joints, antibody present, complication)

<4 involved joints during the first 6 months; Girl age 1-3 years; Knee > ankle > fingers, ANA positive, asymptomatic chronic iritis/uveitis

What defines Polyarticular RF negative JIA? (Demographic, joint number, common joint)

5+ joints within first 6mo, RF negative, 1-3yrs or adolescence,TMJ disease, less joints than RF positive, uveitis 15-20%

What characterizes RF-positive Polyarticular JIA? (Demographic, joint number, resembles)

5+ joints within first 6mo, RF positive disease in teenage females resembling adult RA(antiCCP-erosive), symmetric, RARE uveitis

What defines enthesitis-related arthritis (ERA)? Genetic marker?)

Arthritis with enthesitis or arthritis plus characteristic spondyloarthritis features, presence of HLA B27 antigen,FHx of AS, ERA

What are common sites of enthesitis?

Achilles insertion, plantar fascia, tibial tubercle, patellar insertion

What is another name for Systemic Juvenile Idiopathic Arthritis?

Still disease

What are the hallmark features of systemic JIA ?

Emergent: Arthritis and quotidian fever for 2 weeks + at least 1: salmon colored rash, koeber phenomenon(trauma to skin spreads it), lymphadenopathy, enlarged liver/spleen, serositis

What is a quotidian fever?

Daily fever spike to ~39°C with return to normal between spikes

What rash is associated with systemic JIA?

Transient salmon-colored evanescent rash

What laboratory findings are common in systemic JIA?

High WBCs, anemia, thrombocytosis, elevated ESR/CRP, elevated ferritin

What is the most feared complication of systemic JIA?

Macrophage activation syndrome (MAS)- uncontrolled activation and expansion of T cells and macrophages leading to overwhelming systemic inflammatory response

What causes macrophage activation syndrome?

Uncontrolled activation of T cells and macrophages

What treatments are used for MAS?

Steroids, anakinra, canakinumab, tocilizumab, cyclosporine

What are the major complications of JIA?

Uveitis, Macrophage Activation Syndrome, TMJ disease, limb-length discrepancy, contractures, muscle atrophy, psychological effects

What type of eye disease occurs in JIA?

Chronic anterior uveitis

In which JIA subtype is uveitis most common?

Oligoarticular JIA

Is JIA-associated uveitis usually symptomatic or asymptomatic?

Usually asymptomatic

What late symptoms may occur with JIA uveitis?

Eye pain, redness, photophobia, vision changes

What eye complications can result from untreated uveitis?

Synechiae, cataracts, band keratopathy

What growth abnormality can result from JIA?

Limb-length discrepancy

What muscle finding is commonly seen in JIA?

Muscle atrophy

What jaw complication can occur in JIA?

TMJ (Temporomandibular Joint) disease with abnormal jaw growth

What is first-line local treatment for oligoarticular JIA?

Intra-articular triamcinolone injection

What are advantages of intra-articular steroid injections?

Rapid action, prolonged effect, reduced synovitis

What is the main conventional DMARD used in JIA?

Methotrexate

What factors predict a worse prognosis in JIA?

Early hand involvement, systemic disease, prolonged active disease

Acute Rheumatic Fever criteria

JONES: Joint(arthritis), Carditis, Nodules, Erythema, S>chorea