Juvenile Arthritis (JA), also known as Juvenile Idiopathic Arthritis (JIA), is an umbrella term for a group of autoimmune and inflammatory conditions that affect children under the age of 16. It causes persistent joint inflammation, pain, stiffness, and swelling, potentially leading to long-term damage if untreated.
Types of Juvenile Arthritis
There are several types of JA, each with different characteristics:
- Oligoarticular JIA:
- Affects fewer than five joints in the first six months.
- Commonly affects large joints (knees, ankles, elbows).
- Eye inflammation (uveitis) is common in this type.
- Polyarticular JIA:
- Affects five or more joints in the first six months.
- Can involve both large and small joints (hands, knees, feet).
- Subtypes include rheumatoid factor-positive and rheumatoid factor-negative forms.
- Systemic JIA (Still’s disease):
- Affects the entire body, not just the joints.
- Symptoms include high fevers, rash, and inflammation of internal organs like the liver and spleen.
- This type can be more severe due to systemic involvement.
- Enthesitis-related JIA:
- Involves inflammation where tendons or ligaments attach to bones (entheses).
- Commonly affects the spine, hips, and knees.
- Often associated with a family history of conditions like ankylosing spondylitis.
- Psoriatic JIA:
- Associated with psoriasis, a skin condition that causes red, scaly patches.
- Symptoms may include swollen fingers or toes (dactylitis) and nail pitting.
- Undifferentiated JIA:
- Does not fit into any of the specific subtypes or may have overlapping features of different types.
Causes
The exact cause of juvenile arthritis is unknown, but it is believed to result from a combination of genetic predisposition and environmental factors that trigger an abnormal immune response. The immune system mistakenly attacks the body’s own tissues, causing inflammation in the joints and sometimes other parts of the body.
Symptoms
- Joint pain: Often worse in the morning or after periods of inactivity (morning stiffness).
- Swelling: Joints may become visibly swollen or feel warm to the touch.
- Stiffness: Reduced range of motion in affected joints, especially after rest.
- Fatigue: Children may feel tired or run-down.
- Eye problems: Inflammation of the eye (uveitis) can occur, especially in oligoarticular JIA.
- Growth issues: Inflammation can affect bone growth and development.
Diagnosis
Diagnosis is often based on:
- Physical examination: Swelling, tenderness, and range of motion in the joints.
- Blood tests: To check for inflammation markers (C-reactive protein, ESR), autoantibodies (rheumatoid factor, ANA), and to rule out other conditions.
- Imaging: X-rays, ultrasound, or MRI to assess joint damage or inflammation.
Long-term Outlook
With early and aggressive treatment, many children with JA can achieve remission, where symptoms disappear for an extended period. However, juvenile arthritis can have long-term effects, including joint damage, growth problems, and eye inflammation, so regular monitoring and treatment adjustments are crucial.
Children with JA benefit from a multidisciplinary approach involving pediatricians, rheumatologists, physical therapists, and sometimes ophthalmologists for eye issues.