Juvenile Idiopathic Arthritis COPY Flashcards
Define Juvenile Idiopathic Arthritis
- Group of systemic inflammatory disorders affecting children <16 y/o
- The most commonly diagnoses rheumatic disease in children
- An important cause of disability blindness
Causes of JIA
- Autoimmune disease
- Multifactorial + different from adult RA
- Genetic, environmental, immunological
Criteria for diagnosis of JIA
-Age of onset <16 y/o
->6 week duration of disease
-Presence of arthritis
Joint swelling OR 2 from the following
Painful/limited joint motion
Tenderness
Warmth
Subtypes of JIA
-Pauciarticular (55%)
-Polyarticular (25%)
-Systemic onset (20%)
-
Most common subtype of JIA and its subtypes
- Pauciarticular
- Type 1, 2, 3
Presentation of pauciarticular JIA
- <5y/o (peak age 1-3)
- Girls:boys = 8:1
- Limp rather than pain
- Mainly lower limb joints
- Knee>Ankle>Hand/Elbow (hip v rare)
- +ve ANA in 40-75%
- Irregular iris due to posterior synechiae (iris adheres to lens)
- Chronic uveitis in 20%
What presenting symptom is increased in rate in girls <2y/o
Chronic uveitis (95% from 20%)
Presentation of type 2 pauciarticular JIA
- > 8/9y/o
- Boys:Girls = 7:1
- Limp due to lower limb affection
- Mainly knee + ankle
- Hip can be affected with rapid damage (requiring THR)
In type 2 pauciarticular JIA what may the hip damage lead to
- THR
- Enthesitis
- AS or spondyloarthritis
Presentation of type 3 pauciarticular JIA
-Any age during childhood
-Girls:boys = 4:1
-Asymmetric upper + lower limb arthritis
-Dactylitis (inflamed finger)
-Can be v destructive
-
FHx of psoriasis in 40%(child may develop psoriasis later in life)
-+/-nail pitting
-Chronic iridocyclitis
How many joints need to be affected to classify JIA as polyarticular JIA
5 or more
How many joints need to be affected to classify JIA as pauciarticular JIA
4 or less
Most common type of JIA
Pauciarticular arthritis
Presentation of polyarticular JIA when RF is -ve
-Any age, often early
-Girls:boys = 9:1
-Systemic features (low grade fever + malaise)
-Hepato-splenomegaly
-Mild anaemia
-Growth abnormalities
-Symmetric large + small joints affection (knees, wrists, ankles, MCPs, PIPs, neck)
-Iridocyclitis is rare
-
Presentation of polyarticular JIA when RF is +ve
- Late childhood (12-16y/o)
- Girls:boys = 7:1
- Systemic features (low grade fever, malaise, weight loss)
- Anaemia
- Nodules
- Similar to adult RA
What may be seen on X-rays of RF +ve polyarticular JIA
Erosions may occur early
What may complicate RF +ve polyarticular JIA
-Vasculitis
-AR
-Pulmonary fibrosis
and others
What is rare in both RF +ve and -ve polyarticular JIA
Iridocyclitis
Least common but most serious subtype of JIA
Systemic onset JIA
What defines systemic onset JIA
Extra-articular features (start early and disappear after 2-5 years)
Systemic onset JIA AKA
Still’s Disease
Presentation of systemic onset JIA
- Throughout childhood (4-6 years)
- Girls:boys = 1.5:1
- Fever
- Rash
- Non-tender lymphadenopathy
- Abdo pain
- Hepato-splenomegaly
- Polyserositis, pericarditis
- Arthritis in knees, wrists, ankles, C-spine, hips and TMJ
Describe the fever seen in systemic onset JIA
- Rise to 39.5 daily for at least 2 weeks
- Late afternoon/evening + returns to normal/subnormal in morning
- Child appears toxic with fever +/- chills but looks well when fever goes away
Describe the rash seen in systemic onset JIA
- Evanescent salmon red eruption
- On trunk + thighs
- Accompanies fever
- Can be brought by scratching (+ve Koebner’s phenomenon)
- Occurs in 90%
What are rare CVS and resp. presentations of systemic onset JIA
- Tamponade
- Myocarditis
- Pulmonary fibrosis
- Pleural effusion
When is the arthritis seen in systemic onset JIA
Within first 3-12 months of onset of fever
Investigations for systemic onset JIA
- ESR (very high)
- ASO(elevated with no evidence of recent strep infection)
Investigations for polyarticular JIA
-RF
Investigations for pauciarticular JIA
-ANA (antinuclear antibodies)
Rx of JIA
-Simple analgesics
-IA NSAIDs/steroids
If no response
-Methotrexate
-Anti-TNF (if methotrexate fails)
Physio + Occ therapy
Indication for systemic steroids in JIA
- Systemic onset JIA
- Serious complication with any disease (Pericardial effusion, tamponade, vasculitis)
- As a bridge between DMARDs
- Children undergoing surgery
Risk of using systemic steroids
- Osteoporosis
- Infections
- Growth abnormalities
Surgical Rx for JIA
- Synovectomy
- Reconstructive/joint replacement