Juvenile rheumatoid arthritis
Affecting children younger than age 16, juvenile rheumatoid arthritis (JRA), also known as juvenile chronic arthritis, is an immune-mediated inflammatory disorder of the connective tissues characterized by joint swelling and pain or tenderness. It may also involve such organs as the skin, heart, lungs, liver, spleen, and eyes, producing extra-articular signs and symptoms.
JRA has three major types: systemic (Still’s disease or acute febrile type), polyarticular, and pauciarticular. Depending on the type, this disease can occur as early as age 6 weeks—although rarely before 6 months—with peaks of onset between ages 1 and 3 and 8 and 12. It’s considered the major chronic rheumatic disorder of childhood; overall incidence is twice as high in girls, with variation among the types.
Causes
JRA is thought to be an autoimmune disorder. Research has linked causation to genetic and immune factors. Viral or bacterial (particularly streptococcal) infection, trauma, and emotional stress have been identified as precipitating factors.
Signs and symptoms
Signs and symptoms vary with the type of JRA.
Systemic JRA
Affecting boys and girls almost equally, systemic JRA accounts for 20% to 30% of cases. Affected children may have mild, transient arthritis or frank poly-arthritis associated with fever and rash.
Clinical TipJoint involvement may not be evident at first, but the child’s behavior may clearly suggest joint pain. Such a child may want to constantly sit in a flexed position, may not walk much, or may refuse to walk at all. Young children with JRA are noticeably irritable and listless.
Fever in systemic JRA occurs suddenly and spikes to 103° F (39.4° C) or higher once or twice daily, usually in the late afternoon, then rapidly returns to normal or subnormal. (This sawtooth, or intermittent spiking, fever pattern helps differentiate JRA from other inflammatory disorders.) When fever spikes, an evanescent rheumatoid rash typically appears, consisting of small, pale or salmon pink macules, most commonly on the trunk and
proximal extremities and occasionally on the face, palms, and soles.
proximal extremities and occasionally on the face, palms, and soles.
Massaging or applying heat intensifies this rash, which is usually most conspicuous where the skin has been rubbed or subjected to pressure, such as that from underclothing.
Other signs and symptoms of systemic JRA include hepatosplenomegaly, lymphadenopathy, pleuritis, pericarditis, myocarditis, and nonspecific abdominal pain.
