Juvenile idiopathic arthritis (JIA)

Juvenile Idiopathic Arthritis (JIA) is a chronic autoimmune inflammatory disease affecting children and adolescents under the age of 16. It encompasses a spectrum of phenotypes with varying clinical presentations, disease courses, and prognoses.

JIA is classified into several subtypes:

  • Oligoarticular JIA (persistent or extended): Involves four or fewer joints (persistent if it remains so, extended if it involves more joints after the initial few months).
  • Polyarticular JIA (rheumatoid factor positive or negative): Affects five or more joints, with or without rheumatoid factor positivity.
  • Systemic JIA: Characterized by arthritis with systemic features like fever, rash, lymphadenopathy, hepatomegaly, or splenomegaly.
  • Psoriatic JIA: Arthritis with psoriasis or a history of psoriasis in the patient or a first-degree relative.
  • Enthesitis-related arthritis: Inflammation at the site of tendon or ligament insertion into bone, with or without arthritis.
  • Undifferentiated arthritis: Doesn't fit into any of the above categories.

Diagnosis involves a comprehensive evaluation including medical history, physical examination, laboratory tests (e.g., inflammatory markers, rheumatoid factor, anti-cyclic citrullinated peptide antibodies), and imaging studies (e.g., X-rays, ultrasound, MRI). It's crucial to exclude other causes of childhood arthritis such as infections or malignancies.

Basic treatment aims to relieve pain, reduce inflammation, preserve joint function, and improve quality of life includes: Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation, intra-articular corticosteroid injections for localized joint inflammation and physical therapy and occupational therapy to maintain joint mobility and function.

Advanced treatment may be necessary for patients with inadequate response to basic therapies or severe disease. Options include:

  • Disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate, sulfasalazine, or leflunomide to suppress disease activity and prevent joint damage.
  • Biologic agents targeting specific inflammatory pathways, such as tumor necrosis factor (TNF) inhibitors, interleukin-6 (IL-6) receptor blockers, or interleukin-1 (IL-1) inhibitors.
  • Regular follow-up visits with a multidisciplinary team including rheumatologists, pediatricians, physical therapists, and occupational therapists are essential for monitoring disease activity, adjusting treatment, managing complications, and addressing the psychosocial aspects of the disease.

The prognosis of JIA varies depending on the subtype, disease activity, response to treatment, and presence of complications. With early diagnosis, aggressive treatment, and close monitoring, many children with JIA can achieve remission or low disease activity and lead normal lives.