Oligoarticular juvenile idiopathic arthritis

oligoarticular juvenile idiopathic arthritis (pauciarticular juvenile idiopathic arthritis)

The term pauciarticular onset refers to involvement of four or less joints. Medium sized joints are usually affected - the knees, ankles, elbows and wrists.

About 5% of children with this form of arthritis have IgA deficiency.

Oligoarticular JIA (Oligo-JIA) is the most common subset of JIA (50-60% of JIA)

• majority of patients are girls with peak age if onset between 1 and 3 years
• it is further divided into
  • persistent - no more than four joints affected during the course of the disease
  • extended - after the initial 6-month period, the total number of affected joints exceeds four (1,2)

Rheumatoid factor is negative but the ANA is positive in around 70%-80% of the patients. In ANA positive patients

• the risk of uveitis is higher
• uveitis (rather than arthritis) is the main disability factor (1)

Patients usually complains of arthritis in 4 or fewer joints during the first 6 months of disease

• at onset
  • symptoms could be sudden or insidious.
  • 50% have monoarthritis
  • morning stiffness may be present (if untreated may become prominent with limpimg)
• affected joints
  • are swollen and often warm (usually not very painful or tender).
  • predominantly involves lower-extremity joints, such as the knee and ankle joint (hip is rarely affected) (1,2)
• uveitis
  • almost always bilateral
  • may be present at diagnosis or later in the disease course
  • chronic anterior uveitis of JIA is often asymptomatic and rarely have symptoms such as erythema, pain, or change in vision
  • most respond to topical steroids

Children may modify their behaviour in order to avoid aggravating the affected joints. This will result in disuse atrophy or joint contractures over time e.g - a child with right wrist arthritis will stop using his dominant hand and switch to use the non dominant left hand (2)

Reference:

• (1) Barut K, Adrovic A, Şahin S, Kasapçopur Ö. Juvenile Idiopathic Arthritis. Balkan Medical Journal. 2017;34(2):90-101.
• (2) Kahn P.Juvenile idiopathic arthritis - an update on pharmacotherapy. Bull NYU Hosp Jt Dis. 2011;69(3):264-76.