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Juvenile arthritis

Evidence: Antibody

Names

Juvenile arthritis
Juvenile chronic arthritis
Juvenile idiopathic arthritis (JIA)
Juvenile rheumatoid arthritis (JRA)
Pediatric rheumatic disease

Description

Juvenile arthritis is a pediatric disorder affecting the joints.  Damage occurs when immune cells penetrate the lining of the joints, causing inflammation.  Patients typically experience joint pain and swelling, which may occur in a flare/remission pattern.  Some subtypes have strong evidence of being autoimmune.

The condition is described as “not a disease, but an exclusion diagnosis” that is made when other causes of joint inflammation lasting more than 6 weeks in a patient 16 years-old or younger cannot be positively diagnosed with another condition.

There are 7 types of juvenile arthritis:

  1. Systemic juvenile idiopathic: arthritis in at least one joint accompanied by fever for 2 weeks or longer.   Other possible symptoms include rash or enlargement of the lymph nodes, liver, or spleen.

  2. Oligoarticular juvenile arthritis (oligoarthritis): arthritis in not more than 4 joints in the 6 months following disease onset. After this point, the condition may remain stable (persistent oligoarthritis), or it may spread to additional joints (extended oligoarthritis). The eyes may also be affected.

  3. Rheumatoid factor positive polyarticular juvenile idiopathic arthritis (polyarthritis and rheumatoid factor positive are alternative terms) has symptoms similar to adult rheumatoid arthritis but occurs in children. Patients typically experience arthritis in a minimum of 5 joints in the 6 months following disease onset. Blood tests reveal the presence of rheumatoid factors, a type of autoimmune antibody. The evidence suggests strongly that this subtype is autoimmune.

  4. Rheumatoid factor negative polyarticular juvenile idiopathic arthritis (polyarthritis and rheumatoid factor negative are alternative terms) marked by the same symptoms as patients with rheumatoid factor positive.  The negative variety is distinguished from the positive variety by an absence of rheumatoid factors in the blood. 

  5. Psoriatic juvenile idiopathic arthritis causes both arthritis and red skin rashes with white scaling (psoriasis). Irregularities in the fingers, nails, or eyes may also occur.

  6. Enthesitis-related juvenile idiopathic arthritis causes discomfort where the bone joins with other tissues, such as tendons and ligaments.  Irritation is frequent in the hips, knees, and feet.  Tissue besides the joints may also become inflamed.

  7. Undifferentiated arthritis describes patients whose symptoms are not compatible with the other 6 categories of juvenile arthritis, or whose presentation includes symptoms from multiple categories.

Some patients experience full relief from symptoms with medical attention, while others experience relapses throughout life.  Treatments are available to control symptoms and improve function.

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Prevalence

US Cases: 29,000 to 38,000 [Harrold 2017]. 44.7 (CI 39.1–50.2) per 100,000 based on children under 15. ARI’s case estimate is based on the US Population under 18, estimated at 74 million in 2020.

Typical Age of onset

16 years or younger

Symptoms

  • Joint pain

  • Stiffness, especially after waking

  • Joint swelling

  • Dry eyes

  • Eye pain

  • Redness in the eyes

  • Vision changes

  • Fever

  • Swollen lymph nodes

  • Rash with scaling

  • Fatigue

  • Loss of appetite

  • High spiking fever