Disease Description (Causes and Symptoms)
- Definition summary: A type of chronic childhood arthritis that begins before age 16 and persists for at least 6 weeks (clinically within the Juvenile idiopathic arthritis/Juvenile rheumatoid arthritis spectrum). Unlike adult RA, involvement of large joints (knees, ankles, etc.) is common.
- Causes/pathophysiology: The exact cause is unknown, but genetic predisposition and environmental factors (such as infections) are thought to trigger immune abnormalities, causing inflammation in the joints and throughout the body. Inflammatory cytokines (e.g., TNF-α, IL-1, and IL-6) are involved in the pathophysiology. In children, rheumatoid factor (RF) is often negative.
- Major subtypes and characteristics
- Systemic: Fever (mainly in the afternoon to evening), salmon-colored skin rash (2–5 mm), hepatosplenomegaly, lymphadenopathy, and, rarely, pericarditis and vasculitis. Life-threatening complications such as MAS (macrophage activation syndrome) may occur.
- Oligoarticular (≤5 joints): The most common type in children (approximately 50%). Mainly involves large joints. Asymptomatic uveitis (especially when ANA-positive) is common, so regular ophthalmologic examinations are necessary.
- Polyarticular (≥5 joints): In some children, the disease progresses similarly to adult RA. RF may be positive, resulting in a different prognosis.
- Main symptoms: Joint stiffness (especially in the morning), joint pain, joint swelling, redness, and warmth, limping/avoidance of activity, limited jaw-joint movement, and stiffness and pain when spinal symptoms are present. In the systemic type, high fever, rash, hepatosplenomegaly, and other symptoms may accompany the condition.
- Risk of complications: Vision impairment due to chronic uveitis (which may lead to blindness), growth delay/localized growth disturbance (e.g., micrognathia), joint destruction and deformity, cardiac, pulmonary, and hematologic complications (systemic type), and MAS (risk in the systemic type).
Treatment Methods
- Treatment goals: Relieve pain, maintain joint mobility, preserve muscle strength, prevent complications (especially uveitis), and promote normal growth and development.
- Pharmacological treatment
- NSAIDs: Relief of initial symptoms (e.g., ibuprofen, naproxen).
- Topical/intra-articular steroids: Control of symptoms in specific joints.
- Systemic steroids: Used to control acute symptoms or severe inflammation in the systemic type (the risks to growth and infection associated with long-term use must be considered).
- Oral/injectable disease-modifying antirheumatic drugs (DMARDs): Methotrexate (MTX) is the standard first-line DMARD. Sulfasalazine, antimalarial drugs, and gold preparations may be used in some cases.
- Immunosuppressants: Azathioprine, cyclosporine, cyclophosphamide, and others may be used in refractory cases or specific situations.
- Biologics: TNF inhibitors (such as etanercept and adalimumab), IL-6 inhibitors (tocilizumab), IL-1 inhibitors (anakinra and canakinumab), and others. In particular, IL-1/IL-6 inhibition may be effective in the systemic type.
- Nonpharmacological treatment
- Physical and occupational therapy: Maintaining joint range of motion, strengthening muscles, correcting gait, and using braces/splints.
- Exercise and recreation: Activities that place less stress on the joints, such as swimming and cycling, are recommended.
- Nutritional management and growth monitoring.
- Surgical treatment
- In cases of joint stiffness, subluxation, or severe deformity, arthroplasty, corrective surgery, joint replacement, and other procedures may be considered. In children, the timing of surgery must be carefully determined until bone growth is complete.
- Precautions (related to treatment)
- Increased risk of infection during immunosuppressive treatment → Seek medical attention immediately if fever or symptoms of infection occur.
- Tuberculosis testing and vaccination status must be checked before starting biologics (administration of live vaccines is restricted during immunosuppression).
- Long-term steroid use may cause side effects such as growth retardation, osteoporosis, and weight gain.
- Regular ophthalmologic examinations are essential (especially for patients with the oligoarticular type and ANA-positive patients).
- Psychosocial support for children (adjustment at school and home) is important.
Checklist Before an Outpatient Visit (Including Example Questions)
- Items to prepare
- A list of currently taken medications (name, dosage, and start date)
- Copies or records of previous test results (blood tests, imaging tests, ophthalmologic findings, etc.)
- Records of symptom changes: areas of pain, timing (whether morning stiffness is present), fever patterns, and any limitations in walking or activities
- Effects on daily life: sleep, school attendance and activities, eating, and changes in growth
- Vaccination records
- Useful items to record for the outpatient visit
- Pain diary (pain severity, triggers, and ways of relieving it)
- Notes on the effects and side effects of medications
- Whether eye discomfort, redness, or changes in vision are present
- Items to show/provide to the doctor during the outpatient visit
- Medication list and recent temperature records
- Photos or videos showing mobility (walking) or joint deformities
- Example questions before the outpatient visit (for the patient/guardian to check themselves)
- Has there been a recent fever? Is there a pattern by time of day?
- Has there been eye redness or pain, or any change in vision?
- Are there greater limitations in daily activities (walking/exercise/school life)?
Examples of General Questions to Ask the Doctor
- What are the expected effects and possible side effects of this medication?
- What is the prognosis of the current condition, and what is the long-term management plan?
- Which vaccinations should be received, and by when? (Considerations before and during immunosuppression)
- What lifestyle precautions should be followed to reduce the risk of infection?
- How will the effects on growth and development be monitored?
Examples of Disease-Specific Questions
- Is our child at risk of uveitis (eye inflammation)? How often should ophthalmologic examinations be performed?
- If methotrexate or a biologic is started, how should school activities or exercise (swimming and physical education) be adjusted?
- What are the early signs of macrophage activation syndrome (MAS) in patients with the systemic type, and what immediate action should be taken if it is suspected?