Juvenile Idiopathic arthritis

Rheumatology classification of JIA

Systemic arthritis (10–20%)

Oligoarthritis (50–60%)

Polyarthritis (20–30%) (rheumatoid factor negative)

Polyarthritis (5–10%) (rheumatoid factor positive)

Psoriatic arthritis (2–15%) – Psoriasis associated

Enthesitis related arthritis (1–7%)- HLAB27 associated

Clinical features

Pain in the joints especially in the morning 

Swelling. Joint swelling is common but is often first noticed in larger joints such as the knee.

Morning Stiffness in the joints.

Fever

Swollen lymph nodes

Rash

Extra-articular manifestations

Uveitis

cataract,

band keratopathy,

glaucoma

macular oedema

Growth failure in JIA (secondary to prolonged disease activity and the frequent need for prolonged oral corticosteroid therapy. Growth hormone is sometimes used with short stature associated with JIA

Investigations

The diagnosis of JIA is essentially a clinical one. Therefore, laboratory investigations are used to confirm the diagnosis

Preliminary investigations include

FBE

ESR

CRP

The RACGP guidelines recommend that these be performed if symptoms are present for more than 4 weeks.

FBC may show anaemia of chronic disease if there has been longstanding inflammation.

White cell count is often moderately elevated at diagnosis,

Rheumatoid factor (RF) should be performed in patients with polyarthritis as its presence has prognostic significance

ANA confers risk for the development of asymptomatic uveitis.

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are not routinely tested in JIA,

The RACGP guidelines suggest that imaging be performed if symptoms are present for more than 4 weeks. Further imaging, such as whole-body bone scan and magnetic resonance imaging (MRI), is usually performed by paediatric rheumatologists if needed

Differential diagnosis of JIA 

Septic arthritis •

Post infective/reactive arthritis •

Systemic lupus erythematosus •

Acute lymphoblastic leukaemia •

Trauma •

Osteomyelitis

Inflammatory bowel disease •

Henoch-Schönlein purpura or another vasculitis •

Rheumatic fever

Treatment

NSAIDs

Corticosteroid therapy

Methotrexate

Biologic agents, such as tumour necrosis factor-alpha (TNF-α)