Laboratory Findings in Juvenile Rheumatoid Arthritis The only way to keep up with the latest about Rheumatoid, Arthritis,Juvenile,synovitisoligoarthritis is to constantly stay on the lookout for new information. If you read everything you find about Rheumatoid, Arthritis,Juvenile,synovitisoligoarthritis, it won't take long for you to become an influential authority.
Hematologic abnormalities often reflect the degree of systemic or articular inflammation, with elevated white blood cell and platelet counts and decreased hemoglobin concentration and mean corpuscular volume. The ESR and CRP usually mirror these findings, along with elevated serum immunoglobulins. It is not unusual for the ESR to be normal in some children with chronic arthritis. Elevated ANA titers are present in at least 40–85% of children with oligoarticular or polyarticular JRA, but are unusual in children with systemic-onset disease. ANA seropositivity is associated with increased risk for the development of chronic uveitis in a child with limited joint disease.
Rheumatoid-factor (RF) seropositivity may be associated with onset of polyarticular involvement in an older child (?8%) and the development of rheumatoid nodules, and with a poor overall prognosis with eventual functional disability. Both ANA and RF seropositivity occur in association with transient events during childhood, such as viral infections, particularly Epstein-Barr virus. Bone mineral metabolism and skeletal maturation are often abnormal in children with JRA with a history of active synovitis, relatively independent of onset type or course subtype, and predominantly affect appendicular cortical bone, with less effect on the normal age-related development of trabecular bone. Increased levels of cytokines such as IL-6 may decrease bone formation (reflected by decreased serum levels of osteocalcin and bone-specific alkaline phosphatase) to a greater extent than bone resorption (which may also be decreased, as reflected by decreased levels of tartrate-resistant acid phosphatase). Abnormalities of skeletal growth become most prominent during the pubertal growth spurt and in postpubertal children (Tanner stages IV–V) and lead to failure of the child to achieve acceptable peak bone mass (osteopenia).
Early radiographic changes of arthritis include soft tissue swelling, regional osteoporosis, and periosteal new-bone apposition about affected joints . Regional epiphyseal closure may be stimulated, and local bone growth decreased. In large joints, linear growth may be accelerated and limb length discrepancy, especially with involvement of a knee, becomes prominent. Characteristic radiographic changes in cervical spine, most frequently in the neural arch joints at C2-3 may progress to atlantoaxial subluxation.
Clinical Manifestations of Juvenile Rheumatoid Arthritis
Juvenile rheumatoid arthritis (JRA) is a common, rheumatic disease of children and a major cause of chronic disability. It is characterized by a synovitis of the peripheral joints manifesting in soft tissue swelling and effusion.
In the Classification Criteria of the American College of Rheumatology (ACR), JRA is regarded not as a single disease but as a category of diseases with three principal types of onset:
(1) oligoarthritis or pauciarticular disease,
(2) polyarthritis, and
(3) systemic-onset disease.
Initial symptoms may be subtle or acute, and often include morning stiffness and gelling, easy fatigability, particularly after school in the early afternoon, joint pain later in the day, and objective joint swelling. The involved joints are often warm, resist full range of motion, are painful on motion, but are not usually erythematous.
Oligoarthritis (pauciarticular disease) predominantly affects the joints of the lower extremities, such as the knees and ankles . Often, only a single joint is involved at onset. Isolated involvement of upper extremity large joints is not characteristic of this type of onset. Hip disease may occur later, particularly in polyarticular JRA, and is often a component of a deteriorating functional course.
Polyarthritis (polyarticular disease) is generally characterized by involvement of both large and small joints of both upper and lower extremities . Polyarticular disease may resemble the characteristic presentation of adult rheumatoid arthritis and the HLA profile is often similar. Micrognathia reflects chronic temporomandibular joint disease. Cervical spine involvement of the apophyseal joints occurs frequently with a risk of atlantoaxial subluxation and potential neurologic sequelae.
Systemic-onset disease is characterized by arthritis and prominent visceral involvement that includes hepatosplenomegaly, lymphadenopathy, and serositis, such as a pericardial effusion. Each febrile episode is frequently accompanied by a characteristic faint, erythematous, macular rash; these evanescent salmon-colored lesions may be linear or circular, from 2–5 mm in size, and are often distributed in groups with a linear distribution most commonly over the trunk and proximal extremities . This rash is not pruritic. Its most diagnostic feature is its transient nature, with a group of lesions usually lasting <1 hr. The Koebner phenomenon, which is cutaneous hypersensitivity to superficial trauma resulting in a localized recurrence of the rash, is suggestive, but not diagnostic, of systemic-onset disease.
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