Do you, as a young individual, have concerns over sudden, persistent joint pain or swelling? Or are you a parent worried about these unexplained presentations in your child? Juvenile idiopathic arthritis (JIA) is an established rheumatological disorder which is characterised by these symptoms amongst others, and this article will provide you with additional information outlining the different types of JIA, how it’s diagnosed, managed, and treated, to broaden your understanding of this disorder. If you feel after reading this article that you or your child may have JIA, it is important for you to get in contact with a doctor as soon as possible for a diagnosis and to relieve any pain.

Overview

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatological disorder and is the umbrella term for all types of chronic childhood arthritis which manifests before 16 years old and is persistent for a minimum of 6 weeks. Its occurrence varies between every 1.6-23 new cases for every 100000 children, and in the UK around 15000 children are affected.^2,3 Arthritis refers to the inflammation of joints which results in pain, swelling, and stiffness. As it is idiopathic, the causation of this disorder is not well understood, however, JIA has been classified as an autoimmune disease. An autoimmune disease refers to when the body’s immune system attacks healthy cells, and in the case of JIA, the immune response results in chronic inflammation of joints which characterises the signs and symptoms of this disease. JIA persists from a few months to years or can be a lifelong disorder which requires treatment into adulthood.¹

Types of Juvenile Idiopathic Arthritis

According to the International League of Associations for Rheumatology (ILAR), there are seven types of JIA which differ due to their phenotype, determined by the interaction between your environment and genetics.^2,4

• Oligoarthritis: the most common type of JIA which affects <4 of larger joints such as the knees, ankles, and elbows.
• Rheumatoid factor positive polyarthritis and Rheumatoid factor negative polyarthritis: found in approximately 25% of children with JIA and is characterised by >5 large and small joints on both sides of the body being affected simultaneously.
• Systemic arthritis: affects around 10% of children with JIA and is not limited to the joints but impacts the entire body including the skin and internal organs.
• Psoriatic arthritis: affects >1 joint usually the fingers, wrists, knees, ankles, and toes, and presents with a rash 
• Enthesitis-related arthritis: most common in children between the ages of 8 to 15 years old where the muscles, ligaments, and tendons attached to the bone are affected in areas such as the hip and knees
• Undifferentiated arthritis: characterised by inflammation presenting with symptoms which don’t fit the other subtypes of JIA

Signs and symptoms of Juvenile Idiopathic Arthritis

• Swollen, inflamed and stiff joints particularly hands, knees, ankles, elbows, and wrists
• Fatigue
• Dry eyes
• Fever
• Rash
• Loss of appetite

Management and treatment for juvenile idiopathic arthritis 

There is no cure for JIA, however, varied treatments are available to help relieve the symptoms associated with each subtype of this disorder.

Treatments include:⁴

• Traditional disease-modifying antirheumatic drugs: a type of drug which aims to suppress the immune system to prevent it from attacking the body’s joints.
• Biologics: a type of drug which is  target processed in the inflammatory pathway to reduce inflammation.
• Nonsteroidal anti-inflammatory drugs: used to relieve joints of pain.
• Analgesics: used to relieve joints of pain.
• Surgery: involves the replacement of affected regions of joints with a metal prosthesis, (arthroplasty) fusion of joints (arthrodesis), or realigning of the bone (osteotomy), for children who experience loss of joint function and/or do not experience pain relief from medications.
• Physiotherapists or occupational therapists: Trained individuals who can help children strengthen their muscles, build on weaker motor skills and restricted movement, and can prescribe assistive devices such as splints.
• Exercise: regular low-impact exercises such as walking and swimming are beneficial to reduce stiffness of joints.

Diagnosis

There is no specific test to diagnose JIA, however, doctors are able to run other tests to rule out other conditions that have similar presentations. 

This includes taking a medical history to discuss which symptoms you or your child presents with and when they began, and whether autoimmune diseases exist in the family. A physical examination will be done which checks for pain, inflammation, and/or stiffness of your or your child’s joints, and to identify whether mobility such as walking is affected.¹

Doctors further request blood tests from pathology laboratories such as:

• Full blood count
• Liver function tests 
• Glomerular filtration rate 
• Urea and Electrolytes 
• Erythrocyte sedimentation rate and C-reactive protein: these tests measure inflammatory markers which provide insight into the degree of inflammation and elevated in children with JIA
• Autoantibodies: Autoantibodies are antibodies which attack the self. Therefore, an autoantibody blood test tests for autoantibodies which are typically found in children with JIA, such as antinuclear, rheumatoid factor, anti-cyclic citrullinated peptide, and HLA-B27, which characterise the autoimmune nature of this disorder.¹

Further testing includes:

• X-ray: used to assess the bone structure and is useful to rule out differential diagnoses such as fracture or bone cancer which may contribute to symptomatic joint pain.
• Ultrasounds: used to detect inflammation.
• Magnetic resonance imaging (MRI): used to create 3D images of joints, bones, and their associated inflammation in children with JIA.¹

Complications

The complications associated with medications that suppress the immune system in aim to manage JIA symptoms include the increased risk of infections due to a repressed immune response against bacterial and viral infections.⁵

FAQs

How can I prevent juvenile idiopathic arthritis?

There are no prevention strategies such as vaccinations for autoimmune diseases including JIA, however, there are different ways to manage the symptoms associated with JIA including various medications and exercise for pain relief.

How common is juvenile idiopathic arthritis?

Its occurrence varies between every 1.6-23 new cases for every 100000 children, and in the UK around 15000 children are affected.^2,3

Who is at risk of juvenile idiopathic arthritis?

Children under the age of 16

When should I see a doctor?

If you or your child is under the age of 16 with unexplained joint pain, inflammation, or stiffness which has persisted for 6 weeks or longer.¹

Summary

Juvenile idiopathic Arthritis (JIA) is the most common autoimmune disorder in children, manifesting in children under the age of 16 years old and is identified by persistent joint pain, swelling, and/or stiffness for a minimum of 6 weeks, which can continue into adulthood. There are 7 types of JIA, including Oligoarthritis, Rheumatoid factor positive polyarthritis, Rheumatoid factor negative polyarthritis, Systemic arthritis, Psoriatic arthritis, Enthesitis-related arthritis, and Undifferentiated arthritis. Typical symptoms include swollen, inflamed, and stiff joints, particularly hands, knees, ankles, elbows, and wrists, fatigue, dry eyes, fever, rash, and loss of appetite. JIA cannot be diagnosed directly, however doctors run various tests to rule out other disorders with similar presentations. JIA is incurable, however, medications are prescribed for pain relief, and surgery is carried out in cases where there is a complete loss in function of the joints.