JRA is the most frequent chronic arthritis of children.

The evidence of its was discovered from remained

skeleton from 1000 years ago .

It was prescribed at first in the 1800s, and its criteria established in 1973 .

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Historically, until recently, the terms JRA (in USA),and JCA ( In Europe) ,were used; but recent literatures use JIA instead of them because of :

Only 5-10% of JRA patients havecharacteristic of adult-RF positive RA, so usage ofrheumatoid term may be confusing.

The JRA classification criteria focuses the patternof onset, not the course and progression.

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Epidemiology

. The true prevalence of JRA is not determined, but

estimates about 1 to 2 per 1000.

. The incidence is about 10 to 20 cases per 100000 children.

. It was reported from all of the world and all ethnics.

. Prevalence and in incidence in Iran were not precisely

defined.

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1 3 5 7 9 11 13

10

20

30

40

50 Total

Girls

Years

Pat

ien

t N

um

ber

Boys

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Classically ,JRA subdivided to :

1. Oligoarthritis

2. polyarthritis

3. Systemic onset-disease

Its diagnosis requires to

. Onset before 16th birthday

. Objective arthritis in≥ 1joints

. Exclusion of other causes of

childhood arthritis

for ≥ 6 weeks

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Oligoarthritis

Arthritis in < 4 joints

Persistent type

extended type

at any time during the onset or course of the disease

In first 6 months of disease

but > 5 joints after 6 months

It is the most common type of JRA (60%)

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Manifestations

The typical child with oligoarticular JRA is a girl who is:

. Often the family notices that the child "walks funny" in

the morning, but after a little while seems fine.

. Usually begins at 1-4 years of age

. limping without complaint.

and unusual after

7 years.

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.They are often ANA positive( 65-85%)

.They have the greatest risk of uveitis than other types of JRA

(30-50%) .

.Arthritis usually occurs in large joints

Knee

Ankle

Wrist

Elbow

fingers,toes,hip

Early hip or small joints involvement are unusual

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. Systemic manifestations are characteristically

absent (other than uveitis).

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. Uveitis is the most common complication.

. Leg length discrepancy is another complication

(due to increased blood flow to the inflamed joint) .

. Persistent form has the best articular outcome of all

JRA forms; many cases are benign and resolving

within six months .

Course & Prognosis

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. Up to 50% of oligo JRA progress to extended form

(30% in first 2 years).

Persistent form Extended form

wrist, hand or ankle Involvement

Symmetric Arthritis Arthritis >1 joint ESRPositive ANA

Risk Factors

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Polyarthritis JRA

. It is more frequent in girls than boys (3:1).

. It Is an arthritis in > 5 joints during the first 6 months;

and is second most common type of JRA (30%).

. It has a bimodal distribution of the age at onset

although may occur at any age < 16.1-3 years 8-10 years

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Poly JRA

RF+ RF- (majority)

Usually Girl

Later onset HLA-DR4+symmetric small joint involvement

erosionSubcutaneous nodules prognosis

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Manifestations

. Large joints generally ( knee, wrist,…) involve, but small

joints (hand, foot) too .

. Often the child does not complain pain ,but has pain on

motion.

. Systemic symptoms or sign is not dominant features, but

fever, organomegaly & adenopathy may be present.

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. Apophyseal joint involvement (neck pain),

C1-C2 subluxation & TM joint involvement (micrognathia)

may also occur.

. Uveitis also occurs as in oligoJRA but less often (5%) .

. Many children in the younger age group are ANA positive .

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Course & Prognosis

Onset at later ageEarly involvement of small joints (hand, foot)Hip involvementResistance to treatmentSystemic manifestationsErosionsRF+Nodules

Prognosis

. Prognosis is better for RF- poly JRA than RF+ form, except uveitis that is more common in former.

Arthritis Rheum. 2007 Feb

Systemic-onset Disease

10% of JRA

A child typically 1-6 years (girls=boys), with:

. Fever for ≥ 2 weeks, that is quotidian for ≥ 3 days

(usually afternoon or evening) .

. Characteristic rash

Macule or maculopapule

Transient

Non pruritic

May occur at any site (trunk, proximal of limbs)

and Koebner phenomenon

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. Arthritis

wrists, knees, and ankles is most typical

hand, hip, cervical spine,..

and may occur with other symptoms or weeks to months later .

. Visceral involvement

Hepatomegaly, hepatitis

Splenomegaly

Generalized adenopathy

Pericarditis

Rarely: pulmonary fibrosis, CNS disease

Uveitis is rare in systemic disease

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Leukocytosis, thromboytosis, anemia & ESR, abnormal LFT

common

ANA RF

Rarely +

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Course & Prognosis

The typical child with systemic onset

relative quiescence of

4-6 months period of fever, rash & varying degree of arthritis

systemic manifestations

But up to 50% evolve chronic polyarthritisThe long term prognosis is determined by the severity of arthritis

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Poor prognostic sign

Those with > 6 months of fever, thrombocytosis & need for corticostreoid

Life-threatening complication :Macrophage activating syndrome

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Chronic disease activity may take several different forms

Continue with fever and rash for years, but little progression of their arthritis

Persistent systemic manifestations with progressive arthritis

Resolution of the fever & rash, but have a destructive arthritis

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Ocular involvement

. Uveitis is a serious complication of JRA.

The frequency of it differs by subtype

Oligo

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> poly > systemic

Risk factors

Age at onset of arthritis

Duration of disease

ANA+

Subtype of JRA

Uveitis is often initially silent Screening is necessary

Girls

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Screening

Subgroup Frequency

Any JRA category except SJRA≤ 6 years at onset, ANA +

Any JRA category except SJRA≤ 6 years at onset, ANA -

Any JRA category except SJRA ≥ 7 years at onset, ANA +/-

SJRA

Every 3-4 months for 4 years, then every 6 months for 3 years,then annually

Every 6 months for 4 years,then annually

Every 6 months for 4 years,then annually

Annually

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JRA

Immunologic Factors

Genetic Factors

EnvironmentalFactors

Familial Predisposition(especially in Oligoarticular form)

HLA II genes (DR1,..)

Non HLA-genes

Ethnicity (European descent > Asian or black) Differ in Incidence and subtype Arthritis Rheum. 2007 Jun

(Especially oilgo & poly forms) B cells RF

(poly forms)

ANA(oligo forms)

Immune complex

complement activation

Differ between oligo form & other forms

NK cell activity

Immunologic Factors

Changes in TH1& TH2 cytokines

TNF-α, IL-1, IL-6 & IL-18

IL-10

Regulatory T-cells (in persistent form of oligo and not extended form)

Activity of systemic JRA

Rubella

EBV

Influenza

Chlamydia

May be explain seasonal variations

Environmental

Factors

A trigger (such as an infectious agent)

Physical Trauma

Psychological Factors

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Management

. Management of JRA has many components, that

pharmacotherapy has is only one of which.

. Treatment in most children is prolonged over many years.

. Because of the impact of disease on family and child,

they mast be regard in management.

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. Keeping the child with JRA out of the hospital .

The best management is carried out by multi disciplinary team

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Aim of treatment

Control of pain

Prevention of loss or restoration of range of motion

promotion of normal growth

Considering psychological aspects

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So a comprehensive management needs

physical & occupational therapy

Psychologcal care

Nutritional aspectspharmacologic management

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Growth Retardation& Osteopenia

Disease Effect

Nutrition

Drug side Effects

Mechanical Problems

Control of disease

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Pharmacologic management

Oligoarthritis

Poor response to NSAIDS

Good respoonseto intra-articular corticostroids

. Not responder to

local injections

. Extended Type

. Small Joint

Involvement

Treat like Polyarthritis

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Polyarthritis

. Treat Like adult RA

. MTX should be prescribed early

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Systemic-onset Disease

. Systemic corticosteroids use for arthritis, fever &

serositis .

. Other DMARDS recommend like in polyarthritis; IVIG

occasionally prescribe for systemic manifestations.

. Anakinra recently prescribe as a first DMARD.34

Uveitis

Initial Therapy: Corticosteroids eye drop with mydriasis

Severe Disease

Dependency to Corticosteroids

Immunosuppressive Therapy

Mtx is the cornerstone of treatment

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