Skip to Main Content

Chapter 150: Juvenile Idiopathic Arthritis

Sampath Prahalad

BACKGROUND

Arthritis is inflammation of synovial tissue within a diarthrodial joint*. Infection-related arthritides are discussed in Chapter 152, but idiopathic arthritides constitute another group. Because the pathogenesis of the idiopathic forms is not completely understood, a variety of schemes have been devised to classify childhood arthritides according to the pattern of involvement, associated symptoms, and genetic factors. The classification criteria for juvenile idiopathic arthritis (JIA) proposed by the International League of Associations for Rheumatology is the most current,1 and is followed in this chapter. Based on the number of inflamed joints, laboratory features, family history, and extra-articular features, seven subtypes are recognized: oligoarticular arthritis, rheumatoid factor (RF)-positive polyarthritis, RF-negative polyarthritis, systemic onset JIA, enthesitis-related arthritis (ERA), psoriatic arthritis, or undifferentiated arthritis (Table 150-1).

TABLE 150-1Clinical Features of Juvenile Idiopathic Arthritis
View Table||Download (.pdf)
TABLE 150-1 Clinical Features of Juvenile Idiopathic Arthritis
Type Peak Age of Onset Frequency (%) Typical Features
Oligoarthritis 2–4 years 27–56

Arthritis of ≤4 joints in the first 6 months

Few or no complaints of pain, but swelling is noticeable, especially in large joints

Morning limp or refusal to walk

Girls >> boys
Polyarticular, RF negative 2–4 years 11–28

Arthritis of ≥5 joints for at least 6 weeks

Insidious onset of joint symptoms

Symmetrical distribution

Small joints of hands and feet are commonly involved

Girls > boys
Polyarticular, RF positive Late childhood or adolescence 2–7

Arthritis of ≥5 joints for at least 6 weeks

Symmetrical distribution

Small joints of hands and feet are commonly involved

Early joint erosions

Subcutaneous nodules

Girls >> boys
Systemic onset Throughout childhood 5–15

Quotidian spiking fever

Transient, salmon-colored rash

Systemic features may precede arthritis

Pericarditis and macrophage activation syndrome are potential complications

Girls = boys
Enthesitis-related arthritis Late childhood or adolescence 3–11

Arthritis, more often in lower extremity joints

Enthesitis involving heels, ankles, and knees

Inflammatory spinal pain

At risk for acute iritis

Often positive for HLA B27

Boys >> girls
Psoriatic arthritis

Biphasic

2–4 years,

9–11 years

 2–11

Arthritis and psoriasis

Dactylitis, nail pitting, or family history of psoriasis

Girls > boys
Undifferentiated   11–21 Variable

HLA, human leukocyte antigen; RF, rheumatoid factor.

The diagnosis of JIA is clinical, defined as joint swelling or limitation of joint range of motion with joint pain or tenderness. These signs must be present consistently for at least 6 weeks in a patient younger than age 16 years. The annual incidence of JIA is estimated at 10 per 100,000 children, and the prevalence of JIA in the United States is about 1 in 1000 children younger than 16 years.2 Estimates of the actual number of American children with JIA vary between 70,000 and 100,000, including both active and inactive cases.

*Supported by The National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01-AR060893), The Arthritis Foundation, and the Marcus Foundation Inc., Atlanta, GA.

...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

This site uses cookies to provide, maintain and improve your experience. MH Privacy Center Close