Enthesitis-related juvenile idiopathic arthritis

Other Names: Juvenile enthesitis-related arthritis; Enthesitis related arthritis, juvenile; Enthesitis-related arthritis; ERA; Juvenile spondylarthropathy; Enthesitis-related JIA

Enthesitis-related juvenile idiopathic arthritis is a subtype of juvenile idiopathic arthritis that is characterized by both arthritis and inflammation of an enthesitis site (the point at which a ligament, tendon, or joint capsule attaches to the bone). The knee and the back of the ankle (at the Achilles tendon) are the most commonly affected parts of the body

Cause and inheritance

The underlying cause of enthesitis-related juvenile idiopathic arthritis is currently unknown (idiopathic). It is very rare for more than one member of a family to have juvenile arthritis; however, research suggests that having a family member with juvenile arthritis or any autoimmune disease may increase the risk of having juvenile arthritis, in general.

Risk factors

Most cases of juvenile idiopathic arthritis are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of cases of juvenile idiopathic arthritis have been reported to run in families, although the inheritance pattern of the condition is unclear. A sibling of a person with juvenile idiopathic arthritis has an estimated risk of developing the condition that is about 12 times that of the general population.

Signs and symptoms

Signs and symptoms generally develop in late childhood or early adolescence and include pain, tenderness, and swelling in joints and at the enthesis. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Anterior uveitis
• Elevated C-reactive protein level
• Elevated erythrocyte sedimentation rate(High ESR)
• Joint swelling
• Juvenile [[rheumatoid arthritis]
• Sacroiliac arthritis

30%-79% of people have these symptoms

• Cartilage destruction
• Dental malocclusion(Bad bite)
• Enthesitis

Diagnosis

This subtype of arthritis is diagnosed by the presence of arthritis and enthesitis, or by the presence of arthritis or enthesitis alone with 2 or more of the following features: (1) Presence or history of sacroiliac joint tenderness and/or inflammatory back pain; (2) Presence of the HLA-B27 antigen; (3) Onset of arthritis in a male over 6 years of age; (4) Acute (symptomatic) anterior uveitis; or (5) a history of Ankylosing spondylitis, enthesitis related arthritis, sacroiliitis with Inflammatory bowel disease, or acute anterior Uveitis in a first-degree relative. Enthesitis is tenderness at the insertion sites of tendons, ligaments and fascia caused by inflammation. This type of arthritis is common in adolescent boys and typically affects large joints in the lower limbs, including the hips. It can also involve the Sacroiliac joint and the spine.

Treatment

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Methotrexate oral solution (Brand name: Xatmep) methotrexate oral solution (Xatmep) was approved for the treatment of oligoarticular juvenile idiopathic arthritis (persistent oligoarthritis, psoriatic juvenile idiopathic arthritis, enthesitis-related arthritis, or undifferentiated arthritis) and polyarticular juvenile idiopathic arthritis in children 0 through 16 years of age.

NIH genetic and rare disease info

• NIH info on Enthesitis-related juvenile idiopathic arthritis

Enthesitis-related juvenile idiopathic arthritis is a rare disease.