Juvenile Idiopathic Arthritis Flashcards
What is juvenile idiopathic arthritis?
Group of systemic inflammatory disorders affecting children below the age of 16
Most commonly diagnosed rheumatic disease in children
Important cause of disability and blindness
What is the pathogenesis of juvenile idiopathic arthritis?
Autoimmune disease
Aetiopathogenesis is multi-factorial and different from that of adult RA
Strong subset-specific genetic markers may affect the immune response
What are the criteria for diagnosis of juvenile idiopathic arthritis?
Age of onset < 16 years Duration of disease > 6 weeks Presence of arthritis - joint swelling or 2 of - painful or limited joint motion - tenderness - warmth
After 6 months of JIA, 3 major subtypes can be identified, what will these help to identify?
Natural history
Complications
Prognosis
Strategy of treatment
What are the 3 major clinical subtypes of JIA?
Enthesopathy-related arthritis
Juvenile psoriatic arthritis - oligo or spondylo with psoriasis or potential psoriasis
Others - unclassified under above criteria
What is pauciarticular JIA?
4 or less joints involved
Most common type - accounts for 55% of JIA
What percentage of JIA is accounted for by;
Type 1
Type 2
Type 3
pauciarticular JIA?
Type 1 - 25%
Type 2 - 15%
Type 3 - 15%
What are the features of type 1 pauciarticular JIA?
Majority of pauci Onset < 5 years Peak at 1-3 years Girls:boys 8:1 Positive ANA in 40-75%
What is the clinical presentation of type 1 pauciarticular JIA?
Presentation of limping rather than pain
No constitutional manifestations
Mainly lower limb joints
Knee > ankle > hand or elbow
Hip very rarely affected
Chronic uveitis in 20% of cases, 95% of females < 2 years
Asymptomatic in 50%
Irregular iris due to posterior synechiae
What are the features of type 2 pauciarticular JIA?
15% of pauci
Onset after age 8-9
Girls:boys 1:7
What is the clinical presentation of type 2 pauciarticular JIA?
Mainly lower limb joints affected - knee and ankle
Hip can be affected early with rapid damage requiring THR early in life, may also have enthesitis and may have affected sacro-iliac joints, may evolve AS or spondyloarthritis
Those with HLA-B27 and back involvement will be categorised as juvenile ankylosing spondylitis
20% difficult to classify to a particular spondyloarthropathy group
Acute iridocyclitis in 10-20%
What are the features of type 3 pauciarticular JIA?
15% of pauci
Onset at any age during childhood
Girls:boys 4:1
What is the clinical presentation of type 3 pauciarticular JIA?
Constitutional presentation rare
Presents with asymmetric upper limb and lower limb arthritis, dactylitis
Arthritis may be very destructive
Family history of psoriasis in 40%
Nail pitting
Patients may develop psoriasis later in life
What percentage of children presenting with pauciarticular JIA go on to develop a more severe polyarticular course?
30%
What is polyarticular JIA?
5 or more joints affected
Second most common type - 25%