Juvenile Idiopathic Arthritis

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Original Editors - Emily Betz from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Emily Betz, Lucinda hampton, Jess Bell, Ines Musabyemariya, Admin, Naomi O'Reilly, Khloud Shreif, Kim Jackson, Elaine Lonnemann, Mande Jooste, Wendy Walker, George Prudden, WikiSysop and Meaghan Rieke

Introduction

File:JIA-swollenjoint.jpg

Figure.1 Swollen Right Knee in Patient with JIA

Juvenile idiopathic arthritis (JIA) is used to describe types of arthritis of unknown cause, where symptoms last more than 6 weeks, in individuals aged under 16 years at the time of onset. It is divided into the following types of arthritis:

• oligoarticular
• polyarticular
• systemic
• psoriatic
• enthesitis-related
• undifferentiated

JIA is "characterized by chronic arthritis and hallmarked by elevated levels of circulating immune complexes (CICs) and associated complement activation by-products in their sera."

JIA ranges in severity. It affects the joints, as well as other structures such as the eyes, skin, and organs.

Aetiology

The aetiology of JIA is unclear. The following factors have been proposed:

• genetic associations
• autoimmune factors
• environmental factors (e.g. infectious agents, antibiotics, stress etc) may be risk factors
• infectious viruses and bacteria may be causal factors
• maternal factors (e.g. smoking) may be involved, but breastfeeding / having household siblings may reduce risk

Epidemiology

JIA is the most common chronic heterogenous rheumatologic condition in children. It is estimated that around 3 million children and young adults have JIA. The global prevalence is believed to range from 3.8 to 400/100,000; the incidence is estimated to be 1.6 to 23/100,000.

• Females are at higher risk than males of JIA
• The oligoarticular subtype is more common

Characteristics and Clinical Presentation

File:Uveitis.jpg

Figure.3 Uveitis

Symptoms of JIA vary depending on the type of arthritis. There is a general pattern of inflammatory joint disease or one or more joints:

• synovitis
• joint effusion
• swelling of soft tissues
• osteopenia
• bone oedema, erosions

Individuals may also experience:

• fatigue

• fever
• rash
• feeling generally unwell
• eye inflammation (uveitis)

Diagnostic Tests

JIA is diagnoses according to patient and family medical history, symptoms, number of joints involved, lab tests and sometimes imaging.

Juvenile idiopathic arthritis is diagnosed using a number of tests including:

• medical history
• physical examination
• blood tests – however, most children diagnosed with juvenile idiopathic arthritis do not have rheumatoid factor in their blood, so blood tests do not eliminate juvenile idiopathic arthritis
• x-rays and scans
• eye examination.

Pathology

Figure.2 Prevalence of Major Subtypes of JIA

There are several subtypes of JIA:

1. Oligoarticular JIA (Pauciarticular)
   • affected ≤4 joints in the first six months of illness
   • peak age: 1-6 years
   • mainly affects medium and large joints
2. Polyarticular JIA (pJIA)
   • ≥5 joints are affected
   • peak age: 1-4 years; 7-10 years
   • mainly affects small and medium joints
3. Systemic onset JIA (Still's disease, not to be confused with adult onset Still's disease)
   • arthritis may present weeks to months after the onset of systemic symptoms
4. Enthesitis-related JIA
5. Psoriatic JIA
6. Undifferentiated JIA

Management and Interventions

Treatment of JIA requires anti-inflammatory and immuno-modulatory drugs and physical therapy, and eventually, surgery, nutritional support, and psychosocial support may be needed.

The choice of pharmacological treatment depends on the disease subtypes, disease severity and damage, associated disease, and family acceptance. Non-steroidal anti-inflammatory drugs (NSAIDs) are the mainstay of initial symptomatic treatment for all subtypes. The NSAID use in JIA has decreased over time with modern aggressive treatment, including methotrexate and biologics.

The main treatments for arthritis include:

• medications to control the inflammation (including tablets, injections, infusions, eye drops)
• exercises to keep the joints moving well and the muscles strong
• splints to support the joints
• joint injections to reduce inflammation in particular joints
• pain management strategies to reduce pain and to help your child cope with pain

Pharmacology Management

The doctor will always start with the simplest medications at the smallest doses and work their way up to more complex medications and larger doses depending on how the child’s condition responds to the treatments.

The most common types of medications used for JIA are:

• pain-relievers (analgesics) – for temporary pain relief
• creams and ointments – can be rubbed into the skin over a painful joint to provide temporary pain relief
• eye drops – to treat eye inflammation
• non-steroidal anti-inflammatory drugs (NSAIDs) – to control inflammation and provide pain relief
• corticosteroids – used to quickly control or reduce inflammation. They can be taken as tablets or given by injection directly into a joint, muscle or other soft tissue
• disease modifying anti-rheumatic medications (DMARDs) – work on controlling the immune system. These medications help relieve pain and inflammation, and can also reduce or prevent joint damage
• biologics and biosimilar medicines (bDMARDs) – are also a type of disease modifying drug. They also work on controlling the immune system. However unlike other disease modifying drugs, biologics target specific cells and proteins that are causing the inflammation and damage, rather than suppressing the entire immune system.  

Physiotherapy Management

Physical therapy is an important part of the treatment of JIA. It is important for the child to remain active and involved in sports and activities with their peers and friends. While pain may limit the amount of activity a child can handle it is important to encourage involvement during periods or remission and allow rest and symptom reducing therapies during periods of flare-ups. Regular activity and general exercise programs help to maintain range of motion in affective joints, build and maintain strength, maintain function and can even help with symptom reduction.

Aspects that should be focused on during a physical therapy session are as follows:

• Muscle tone
• Strengthening
• Range of motion
• Stretching
• Education on joint protection
• Home exercise plan
• Education on pain reducing techniques
• Muscle relaxation techniques
• Splints or Introduction to Orthotics maybe be beneficial to help maintain normal bone and joint growth/prevent deformities during growth

Some modalities that can be used to help reduce symptoms such as pain are:

• Ultrasound
• Paraffin wax dips (hands and feet primarily)
• Moist compress (hot pack)
• Hydrotherapy (warm)
• Cold packs

Differential Diagnosis

Some signs and symptoms of JIA are shared with those of the following diseases:

• Lyme Disease
• Rheumatic fever
• Osteomyelitis
• Psoriatic arthritis
• Inflammatory bowel disease
• Leukemia
• Caffey Disease
• Chronic Eosinophilic Granuloma
• Osteoporosis
• Involutional Osteoarthritis

Case Reports/ Case Studies

Juvenile Idiopathic Arthritis Treatment Roundup: What’s Available and What’s Upcoming? https://www.rheumatologyadvisor.com/home/topics/pediatric-rheumatology/juvenile-idiopathic-arthritis-jia-treatment-therapy-strategies-updates-future/

Clinical Trials: Rheumatology Network https://www.rheumatologynetwork.com/clinical/juvenile-arthritis