What is Juvenile Idiopathic Arthritis (JIA)?

From the Guidelines

Juvenile Idiopathic Arthritis (JIA) is a chronic inflammatory condition affecting children under 16 years of age, characterized by joint pain, swelling, stiffness, and potential growth issues, with treatment typically involving a combination of medications and physical therapy to manage symptoms and prevent long-term damage. According to the 2019 American College of Rheumatology guideline for the treatment of JIA 1, the condition encompasses several subtypes, including oligoarticular, polyarticular, and systemic, resulting from an autoimmune response where the immune system mistakenly attacks healthy joint tissues. Some key points to consider in the management of JIA include:

• The use of disease-modifying antirheumatic drugs (DMARDs) such as methotrexate as a first-line treatment for patients without risk factors, with biologic therapy considered for those with high-risk joints, high disease activity, or judged to be at high risk of disabling joint damage 1
• The importance of shared decision-making between the physician, parents, and patient when initiating or escalating treatment, including discussion of recommended treatments and potential alternatives 1
• The role of physical therapy in maintaining joint mobility and muscle strength, as well as regular eye examinations to monitor for uveitis in some forms of JIA. While there is no cure for JIA, proper management with a combination of medications, physical therapy, and regular monitoring can allow most children to lead active lives and potentially experience remission by adulthood. Early diagnosis and treatment are crucial to prevent joint damage and growth complications, with the clinical Juvenile Arthritis Disease Activity Score (cJADAS-10) used to define low disease activity and guide treatment decisions 1.

From the FDA Drug Label

1.4 Polyarticular Juvenile Idiopathic Arthritis (PJIA) ACTEMRA® (tocilizumab) is indicated for the treatment of active polyarticular juvenile idiopathic arthritis in patients 2 years of age and older. 1.5 Systemic Juvenile Idiopathic Arthritis (SJIA) ACTEMRA® (tocilizumab) is indicated for the treatment of active systemic juvenile idiopathic arthritis in patients 2 years of age and older.

1. 2 Polyarticular Juvenile Idiopathic Arthritis Enbrel is indicated for reducing signs and symptoms of moderately to severely active polyarticular juvenile idiopathic arthritis (pJIA) in patients 2 years of age and older.

Juvenile Idiopathic Arthritis (JIA) is not explicitly defined in the provided drug labels. However, based on the indications for treatment, it can be inferred that JIA refers to a group of chronic inflammatory diseases that affect children, including:

• Polyarticular Juvenile Idiopathic Arthritis (PJIA): a type of JIA characterized by inflammation in multiple joints.
• Systemic Juvenile Idiopathic Arthritis (SJIA): a type of JIA characterized by systemic inflammation, which can affect multiple organs and joints. The exact definition and classification of JIA are not provided in the drug labels, and therefore, a conservative clinical decision would be to consult additional resources for a comprehensive understanding of the condition 2, 3, 3.

From the Research

Definition of Juvenile Idiopathic Arthritis (JIA)

• Juvenile idiopathic arthritis (JIA) is an umbrella term for seven or more clinical patterns of arthritis of unknown cause in children 4
• JIA is a chronic inflammatory disease and an exclusion diagnosis that includes all forms of arthritis that persists for more than 6 weeks under the age of 16 5
• JIA comprises a group of heterogenous disorders characterized by childhood-onset chronic joint inflammation 6

Characteristics of JIA

• JIA is the most common rheumatologic disease in the pediatric population and an important cause of chronic illness in children 6
• JIA can have significant complications, including uveitis and macrophage activation syndrome 6
• The etiology of JIA remains incompletely understood, and efforts are underway to refine the classification of JIA 6

Treatment and Management of JIA

• Treatment strategies for JIA have changed significantly in recent years with the availability of multiple newer targeted therapies 6
• Methotrexate remains the first-line disease modifying (DMARD) therapy for most children with JIA due to its proven efficacy and safety 7
• Biological agents, such as tumor necrosis factor inhibitors (TNF-I), have shown tremendous benefit in children with polyarticular JIA, enthesitis related arthritis (ERA), and psoriatic arthritis 7

Long-term Implications of JIA

• A significant portion of patients with JIA require the continuation of treatments in adulthood 8
• Patients with JIA may experience extra-articular manifestations, residual irreversible disabilities, comorbidities related to an inflammatory process, and extended immunosuppressive treatments during the age of development 8