Juvenile chronic arthritis Flashcards
1
Q
JIA (juvenile idiopathic arthritis) - background
A
- Definition = persistent joint swelling >6 weeks presenting before 16y in the absence of infection or any other defined cause
- 95% of children have a disease that is clinically and immunogenetically distinct from RA in adults. Typically starts any time after 1yo
- Commonest chronic inflammatory joint disease in children and adolescents (UK), prevalence 1:1000
- Divided into 7 subsets for research categories; not diagnostic, but useful for clinical groups
- As a child’s symptoms evolve with time (e.g. the appearance of a psoriatic rash), they may change subtypes
2
Q
JIA - classification
A
- Systemic arthritis, acute illness with malaise and high daily fever initially (10-13%)
- Oligoarthritis, 1-4 joints (40%)
- Polyarthritis (rheumatoid factor +ve) (3%)
- Polyarthritis (rheumatoid factor -ve) (27%)
- Psoriatic arthritis (2-15%)
- Enthesitis-related (1-7%)
- Undifferentiated arthritis (2-15%)
3
Q
JIA - symptoms
A
- Gelling (stiffness after periods of rest, e.g. long car rides)
- Morning joint stiffness
- Pain
Young child
- Intermittent limp
- Deterioration in behaviour or mood, or avoidance of previously enjoyed activities (rather than complaining of pain)
Note: before labelling the child with a dx of JIA, it is imperative to exclude the ddx of sepsis, trauma and malignancy.
4
Q
JIA - signs
A
Initially
- Joint effusion
- Synovitis/proliferation and thickening of synovium (?)
- Swelling of periarticular soft-tissues
Long-term
4. Leg length discrepancy/valgus deformity if knee affected
5. Digit length
discrepancy if hands affected
Distinguishing between types:
- Systemic JIA -> fever, salmon-coloured evanescent rash
- Polyarticular JIA -> symmetrical joint involvement, >4 joints
- Oligoarticular JIA -> fewer than five joints affected
- Psoriatic JIA -> skin and nail disease (psoriasis)
- Enthesitis-related JIA -> enthesitis, axial symptoms, positive family history of spondylitis
5
Q
JIA - complications
A
- Chronic anterior uveitis - common but asymptomatic and can lead to severe visual impairment
- Flexion contractures of joints - occur when joint is held in most comfortable position (minimising intra-articular pressure) -> if untx, can lead to joint destruction and the need for joint replacement
- Growth failure (from anorexia, chronic disease and systemic corticosteroid therapy) + localised overgrowth (e.g. leg length discrepancy due to prolonged active knee synovitis)
- Constitutional problems - anaemia of chronic disease, delayed puberty
- Osteoporosis - etiology = diet, reduced weight bearing, systemic corticosteroids and delayed menarche
6
Q
JIA - ix
A
- Bloods (5) = FBE, ESR, CRP, rheumatoid factor, ANA (but ANA non-specific)
- Infection screen (if rash?) = throat swab, urinalysis, blood for ASOT, viral serology (CMV, EBV, parvovirus B19, hepatitis), culture
- X-rays - to exclude fracture or tumour. Early = soft-tissue swelling and juxta-articular osteopenia. Later = joint space narrowing and erosions
- U/S - helpful for confirming synovitis and joint effusion. MRI - for atypical monoarthritis
- Synovial fluid aspirate - culture for sepsis
7
Q
JIA - mx
A
- NSAIDs (initially, e.g. naproxen, indomethacin)
2. Intra-articular corticosteroid therapy under GA in child
8
Q
JIA - prognosis (3)
A
- 1 in 3 have ongoing active disease into adult years
- Morbidity - joint damage requiring joint replacmement surgery, visual impairment from uveitis, fractures from osteoporosis
- Psychosocial morbidity