Juvenile Idiopathic Arthritis Flashcards
What is the definition of juvenile idiopathic arthritis (JIA)?
Group of systemic inflammatory disorders affecting children below age of 16
Most commonly diagnosed rheumatoid disease in children
Important cause of disability and blindness
What is the pathogenesis of JIA?
Is an auto-immune condition
Multi-factorial and different of adult RA
Strong subset specific genetic markers affect immune response
What is the classification criteria of JIA?
Age of onset <16
Duration of disease >4weeks
Presence of arthritis - joint swelling or 2 of : limited or painful joint motion, tenderness or warmth
What are the clinical subtypes of JIA?
After 6 months can be identified
Oligoarticular - 4 or less joints (most common)
Polyarticular - 5 or more joints
Systemic Onset - systemically unwell
What will help to suspect the clinical subtypes of JIA?
Natural history, complications, prognosis and decide the strategy of treatment
What is the incidence of type 1 oligoarticular JIA?
Majority
Age is before 5 years, peak 1-3 years
8:1 girls to boys
Mainly lower limb (knee>ankle> hand or elbow)
What is the presentation of type 1 oligoarticular JIA?
Limp rather than a pain as mainly affects lower limbs
No constitutional manifestations
Look at eyes
+ANA (antinuclear antibody for autoimmune disease) in 40-75%
What is the incidence of eye disease and type 1 oligoarticular JIA?
Chronic uveitis in 20% of cases (95% if female and under 2 years)
Asymptomatic in 50%
Irregular iris due to posterior synechiae
Gradual progressive loss of vision
What is the incidence of type II oligoarticular JIA?
15%
Age after 8-9 years
Girl to boys 1:7
What is the presentation of type II oligoarticular JIA?
Constitutional symptoms are rare and limp due to LL affection- knee and ankle
May have erosions in heel, Achilles tendonitis and rapidly progressive inflammation in hip leading to OA
Describe type II oligoarticular JIA and hip joints
Hips can be affected early with rapid damage requiring THR early in life and enthesitis
Many have sacroiliac joints involved and may evolve to AS or spondyloarthritis
Acute iritis 10-20%
What is the diagnosis if present with HLA-B27 and back involvement?
Juvenile ankylosing spondylitis
What is the incidence of type III oligoarticular JIA?
15%
Age is any during childhood
Girls to boys 4:1
What is the presentation of type III oligoarticular JIA?
Constitutional symptoms are rare, asymmetric UL and LL arthritis and dactylitis (sausage finger or toe)
What is associated with type III oligoarticular JIA?
Arthritis can be very destructive
FH of psoriasis in 40% and possible nail pitting
These patients may develop psoriasis later in life
Chronic uveitis in 10-20%
What is extended oligoarthritis?
30% of these presenting with pauciarticular JIA can more to severe polyarticular course
Feature of poor prognosis
What is the incidence of JIA zero negative (polyarticular)?
15% of JIA
Negative rheumatoid factor
Age is any age and often early
Girls to boys 9:1
What is the presentation of JIA zero negative (polyarticular)?
Constitutional manifestation (low grade fever and malaise), hepato-splenomegaly, mild anaemia and growth abnormalities
Symmetric large and small joint affection - knees, wrists, ankles, MCPs, PIPs and neck
Uveitis is rare
What is the incidence of RF positive polyarticular JIA?
10% of JIA
Age is later childhood (teens, 12-16 years)
Girls to boys 7:1
What is the presentation of RF positive polyarticular arthritis?
Constitutional manifestations, anaemia and nodules
Can be complicated by Sjogren’s, Felty or vasculitis, AR, and pulmonary fibrosis
Similar to adult RA
Erosions in x-ray occur rarely
Uveitis rare
Which type of JIA has the most serious morbidity and mortality?
Systemic onset JIA
What is the incidence of systemic onset JIA (STILL’s disease)?
20% of JIA
Age is throughout childhood (4-6 years)
Girls to boys 1.5:1
What features define systemic onset JIA?
Extra-articular features
Start early and disappear after 2-5 years
Fever, rash, sore throat in absence of infection, abdo pain, pleural effusion, weight loss, pericardial effusion and lymphadenopathy
What can the fever be like in systemic onset JIA?
Rise to 39.5 degrees for at least 2 weeks
Late in afternoon or evening and return to normal/ subnormal in the morning
Child appears appears toxic with fever and possible chills but normal when fever goes away
