Juvenile Chronic Arthritis -

Definition

Heterogeneous group of Inflammatory Joint Diseases with

non-infective aetiology
greater than 3 months duration
age less than 16

Epidemiology

1: 1000
M = F
Different subgroups have association with different HLA types

Aetiology

Unknown
Genetic predisposition with possible infectious trigger
Immune sensitive host
Auto antibodies & possible persistant antigens
Immune complex disease recognised
- Particularly in the JRA form
T helper & suppressor cell types ↑
Autoantibodies include RF & Antinuclear antibodies
- Ie. similar to RA

Classification

Three classification systems & criteria for diagnosis
- Juvenile Rheumatoid Arthritis (American College of Rheumatology)
- Juvenile Chronic Arthritis (European League Against Rheumatism)
- Juvenile Idiopathic Arthritis (ILAR)

Three types JCA

Type	Epidemiology	Description
Systemic JCA	20%	AKA Stills Disease 20%
Pauciarticular JCA	40-60%	4 joints or less in first 3/12 Divided into Early onset (< 6 years) Late onset (> 9 years) Tends to be like AS High incidence of iridocyclitis can go blind need quarterly slit-lamp check-ups
Polyarticular JCA	30-40%	5 joints or more within first 3/12 Divided into Seronegative (85%) Seropositive (15%) = Juvenile RA Tends to be like RA

Types of Juvenille Chronic Arthritis

Clinical Features

Depends on classification

Systemic disease (Stills Disease)

20% cases
M = F
Usually < 3 years
Intermittent
Fevers – up to 40°C
Rashes – maculopapular & erythematous
Malaise
May be ill with intermittent well periods
Less constant features are
- Splenomegaly
- Hepatomegaly
- Lymphadenopathy
- Leucocytosis & Anaemia
Joint involvement usually weeks-months after onset
Usually subsides with the systemic illness
- 25% have > 1 attack
- 50% proceed to chronic arthropathy
- May proceed to polyarthropathy
Joints involved include
- Wrists
- Knees
- Ankles
- Midfoot
Also involves
- Flexor tenosynovitis of fingers
- MCPJ & PIPJ swelling
If persists can extend to
- Hip
- Cervical Spine
May stunt growth & can be abetted (made worse) by earlier use of steroids
Rheumatoid factor & Antinuclear antibodies negative

Pauciarticular arthritis

40% cases & is commonest form
Few joints involved & no systemic illness (4 or less in first 3/12)
Two subgroups
- Onset < 6 years
  - F > M
  - Most commonly affects medium-sized joints
    - Knees
    - Ankles
    - Wrists
    - Hips rarely affected
  - Flexor tenosynovitis
  - PIPJ swelling
  - Generally good joint outcome
    - Resolves after a few years
    - However deformity & growth defects (usually asymmetrical) can occur
  - 10-50% will have evidence of iridocyclitis
    - Usually at time of the disease but may precede by up to 10 years
    - Recommend quarterly Slit Lamp examinations
  - Generally RF negative but ANA positive
- Onset > 9 years
  - M > F
  - Spondyloarthritis picture
    - Sacroilitis & Hip involvement common
    - May involve
      - Knee
      - Ankle
    - Enthesopathy with
      - Plantar fasciitis
      - Achilles tendonitis
      - Tibial tubercle & Patella
      - Greater trochanter
    - Generally see HLA-B27 positive in 50%
  - ANA & RF negative
  - Family history common

Polyarticular disease

40% cases
5 or more joints affected in first 3/12
F > M
Any age affected
Two subgroups
- 1. Seronegative
  - Most common (85%)
  - Similar to Polyarthritis following systemic onset
    - Knees most common but also
    - Wrists & ankles
    - Cervical Spine
    - Hand with flexor tenosynovitis
    - Foot with first MTPJ involvement
  - If persists tends to spread
- 2. Seropositive
  - AKA Juvenile RA
  - Older girls > 8 years
  - Severe disabling disease much more likely to occur
  - Similar to RA
    - Small joints of hands & feet
    - Wrists
    - Nodules
  - Positive rheumatoid factor
  - Rapidly progressive joint destruction can occur

Investigations

Laboratory Tests

Systemic
- ESR > 100
- Increased WCC + Neutrophilia
- Mild Anaemia
- Increased IgG
- Increased CD4 T Cells
- ANA negative
- RF negative
Pauciarticular
- ESR normal or slightly ↑
- Normal WCC & RCC
- ANA may be present
- RF negative usually
Polyarticular
- ESR ~70
- Mildly ↑ WCC
- RF in seropositive subtype

XR

Non-specific changes & soft tissue swelling early
Have severe periarticular (epiphyseal) osteopaenia
Progressive joint erosion & deformity later

Differential Diagnosis

Still’s
- Viral illness
Pauciarticular
- Septic arthritis
- Reiter’s
- TB Synovitis (if subacute)
Unwell Child
- Septic arthritis
- Leukemia
- SLE
- Acute rheumatic fever
- Henoch Schonlein Purpura
Well Child
- Toxic synovitis
- RSD
- PVNS
- Sarcoid
- Lyme disease
- Foreign body synovitis
- Hypermobility syndrome

Management

Counsel parents & patient
Rest
- Avoid prolonged bed rest (required for Stills)
- Avoid contractures
- Prone lying daily
- Resting splints
  - knees / ankles / wrists
- Working splints for
  - Wrist for writing
  - Neck for school work
  - Knees (if weak quadriceps) for walking
  - May require skin traction for acute spasm or contractures of hips / knees
- Splint can rest joint flare-up
Physiotherapy
- Maintain ROM
- Active / Passive ROM
- Minimize muscle wasting
- Daily gentle exercises
Drugs
- NSAID
  - Mainstay of treatment
  - Paediatric suspensions available
  - Avoid salicylates (aspirin) due to Reyes syndrome
- Disease Modifying Drugs
  - IV immunoglobulins in systemic disease
  - In seropositive disease may use Gold & Penicillamine
  - Spondyloarthropathy may use Sulphasalazine
  - Methotrexate in severe disease
  - Steroids
    - Systemic
      - Don’t affect progress of disease
      - Use limited by side affects
      - Growth retardation
      - Osteoporosis
      - Indications
        Stills unresponsive to other treatment
        Polyarthritis unresponsive to other treatment
        Alternate day treatment minimizes stunting
    - Intra-articular steroids
      - Flares of pauciarticular disease
        Knee
        Flexor sheaths
    - Topically used for iridocyclitis

Complications

Growth defects
- Generalized growth retardation
- Worse if use steroids
Epiphyseal disturbances
- External Tibial Torsion
- Dysplasia of Distal Ulna
Dens & Mandible Hypoplasia
Scoliosis
Joint Destruction
- Most common with seropositive disease
Common Deformity
- Protrusio Acetabuli
- Atlanto-axial Subluxation
- MCPJ Subluxation
Fractures
- More common if < 5 with osteoporosis
Iridocyclitis
Pauciarticular disease
- Blindness can occur
- Amyloidosis
Longstanding Stills
- May be fatal

Prognosis

Orthopaedic Interventions
- Early synovectomy
- Late – osteotomy, excision, fusion, epiphysiodesis, arthroplasty
- Anaesthesia referral – JRA has microagnathia & neck issues
Procedures
- Synovectomy
  - Controversial utility
  - Must have adequate trial of medical therapy
  - Also early joint involvement
  - > 6 years of age
  - large joint
  - “complete as is possible”
  - ROM does not improve
- Soft tissue release
  - Goal is to release contractures & improve on pain
- Osteotomy
  - Coorectionj of subluxation & angular deformity
- Arthrodesis
  - Particularly in the wrist, ankle or hindfoot
- Total Joint Arthroplasty
General
- Death uncommon (3%)
  - Two main causes
    - 1. Infection early
    - 2. Amyloidosis late
- 75% enter long remission with little or no residual disability
- Poor outcome more likely with
  - Young age at onset (esp < 1 year)
  - Long active period disease (> 5 years)
Joints
- Hip
  - is most serious joint involved
  - Hip abnormalities & degenerative disease follows
  - Total joint arthroplasty* may be needed for hips & knees but should
    - Be customised
    - Delay until all full bone growth near affected joints
- Arthrodesis in ankle, wrist & subtalar joints can be implemented
- Synovectomy will not alter the course of disease
- 91% Survival 10 year Charnely THR
- Wait until skeletal maturity
- Probably with valgus & anteversion & small medulla
Orthopaedic Considerations
- Synovectomy
  - Most consistent benefit is relief of pain
  - Best early in disease
  - Major side effect is loss of ROM
  - Hence contraindicated in children < 6 due to rehabilitation problems
Injection of joint with Triamcinolone will help settle pauciarticular JCA that not responded to NSAIDS – repeat 6 monthly & never more than 3 injections
Lower Limb
- Release of the ITB & adductors to preserve ROM in increasing deformity
- May need release of Iliopsoas as well
- The early hip disease may benefit from varus osteotomy – particularly if subluxation
- The use of THR has ↑ & proven good short term results
- Use of triple arthrodesis when deformity in hindfoot severe
- Should realign feet first then hip & knee
Upper Limb
- Hand deformity corrected with soft tissue releases
- Wrist fusion often required
- Cervical Spine
- May require fusion if atlanto-occipital instability
Treatment of Growth Problems
- Leg length inequality & valgus deformity at knees common
- Synovectomy in early stages may help equalise the leg length by reducing vascularity about the knee
- Staple epiphysiodesis useful in young child
- Difficulty with small / porotic bones