Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases that affect children under 16 years of age and cause stiff or swollen joints and pain that last 6 weeks or more^1,2,3.

The International League of Associations for Rheumatology (ILAR) classifies JIA into seven different types. Although chronic arthritis is mandatory for all types, they have distinct extraarticular and systemic clinical manifestations, genetic predispositions, and disease course^2,3:

• Oligoarthritis
• Juvenile enthesitis-realted arthritis
• Polyarthritis (it has 2 subtypes)
• Juvenile psoriatic arthritis
• Systemic
• Others

• Fever
  It is the most common symptom of systemic JIA. Fever usually occurs daily at the same time for 2 weeks or more^1,5.
• Rash
  It is the second typical extra-articular manifestation in children who have systemic
  JIA. The rash is usually described as small salmon pink patches. It occurs with fever spikes but may persist when fever is resolved^1,5.
• Eye redness (uveitis)
  It is the most serious complication for all children with JIA. Uveitis is usually painless, but can lead to vision loss^1,5.

The cause and trigger of JIA remain unclear, as it is not known what causes the immune system to malfunction in JIA^2,4.

It is thought that the abnormal immune response is triggered by environmental factors in genetically susceptible individuals².

There is strong evidence for a genetic component to the aetiology of JIA, being the strongest genetic association with genes of the major histocompatibility complex (MHC), which are central to immunity and and inflammatory processes^3,5.

All types of JIA lead to a final common pathway: thickening and inflammation of the joint lining³.

Physical exam and medical history

Diagnosis of JIA based on physical exam and medical history⁴. The following items are essential for diagnosis and classification of JIA²:

• Age of onset
• Affected joints
• Duration of arthritis
• Associated symptoms or diseases
• Physical and musculoskeletal examination

Laboratory tests

Chlidren often test negative for blood tests that are commonly found in adults with rheumatoid arthritis such as rheumatoid factor (RF)⁴. Other inflammatory markers evaluated are²:

• Erythrocyte sedimentation rate (ESR)
• C-reactive protein (CRP)
• Human leukocyte antigen (HLA)-B27

Imaging

Imaging serves to improve the certainty of a diagnosis of JIA and to evaluate joint damage².

• X-rays
• Ultrasound (US)
• Magnetic resonance imaging (MRI)

The best care for children with arthritis is provided by a paediatric rheumatology team that has extensive experience and can diagnose and manage the complex needs of the child and family most effectively⁴.

Pharmacological treatment

NSAIDs
Non-steroidal anti-inflammatory drugs are the most commonly used medicine in JIA as they have analgesic and anti-inflammatory properties⁵.

Corticosteroids
When only a few joints are involved, a steroid can be injected into the joint before any additional medications are given. Steroids injected into the joint do not have significant side effects⁴.

DMARDs
Disease-modifying anti-rheumatic drugs (DMARDs) are added as a second-line treatment when arthritis involves many joints or does not respond to steroid joint injections⁴.  Some DMARDs are known as “biologics”, and all of them may cause side effects that need to be monitored and discussed with the paediatric rheumatologist treating your child^1,4.

Physical and occupational therapies
Physical and occupational therapy can improve children’s quality of life by teaching
them ways to stay active and how to perform daily tasks with ease⁶

Hot and cold treatments
Heat pads or warm baths are useful for soothing stiff joints and tired muscles.
Cold is useful for acute pain⁶

Children with JIA should attend school, participate in extra-curricular and family activities, and live life as normally as possible⁴.

Exercising regularly⁶

• Regular exercise helps ease joint stiffness and pain.
• Low-impact and joint-friendly activities such as walking, swimming, biking and yoga are the best option.
• However, children with well-controlled disease can participate in just about any activity they wish.

Having a healthful diet⁶

• There is no special JIA diet, but consumption of some foods and avoidance of others may help to reduce inflammation
• Foods to include in your child’s diet: fatty fish, fruits, vegetables, whole grains and extra virgin olive oil among others.
• Foods to avoid: high-fat, sugary and processed foods.

Balancing activity with rest⁶

• When JIA is active it is important to balance light activity with rest.
• Rest helps reduce inflammation and fatigue.
• Taking breaks throughout the day protects joints and preserves energy.

Managing stress and emotions⁶

• Children and teens with JIA are more likely to get depressed because they are living with a chronic disease.
• It is important to have a strong support system of friends and family that can provide emotional support during tough times.