Juvenile idiopathic arthritis (AIJ)

There are various types of JIA which can be identified by the number of joints affected and the presence of symptoms such as fever and skin manifestations, amongst others. The diagnosis is made by observing the symptoms during the first 6 months of the disease.

Symptoms

The main symptoms are pain, swelling and increased heat in the joints, with stiffness and difficulty moving. Sometimes the beginning is slow, insidious and progressive. The child may be tired or irritable, if they are younger. Older children may notice stiffness when moving their joints when they get up in the morning. At other times, the beginning is acute and serious, with the presence of general symptoms such as general malaise, fever, blemishes on the skin and several swollen joints.

Who is affected by the condition?

JIA is a relatively rare condition that affects 1 or 2 children in every 1,000.

How is it diagnosed?

JIA diagnosis is based on the presence of persistent arthritis and carefully excluding any other condition by using the clinical history, physical examination and blood tests. 

JIA is considered where the condition begins before the age of 16, the symptoms last for more than 6 weeks and other conditions that may be responsible for arthritis have been discounted.

Standard treatment

The treatment must be put in place early and each child must be considered individually, which means that the therapy will have different levels of intensity depending on the type, time and seriousness of the condition.

Its aim is to care for the child’s all-round physical and psychological development, to try and improve all aspects of their quality of life.

To ensure that there are no after-effects, or that these are minimised, there must be ongoing effort and close collaboration between the child and their parents or family and the various specialists. It is essential that the family understands this disease. The child will begin to learn about it according to their age. 

Standard tests

When it comes to diagnosis, certain analytical tests are valuable, along with examinations of the joints and eye tests for a better definition of the type of JIA and identification of the patients at risk of developing specific complications, like chronic iridocyclitis.

The rheumatoid factor (RF) test detects this autoantibody which, if positive and found persistently in high concentrations, indicates a subtype of JIA.

Antinuclear antibodies (ANA) usually test positive in tests on patients with early onset oligoarticular JIA. The population of patients with JIA has a greater risk of developing chronic iridocyclitis and, therefore, eye tests using a slit lamp should be scheduled (every three months).

HLA-B27 is a cellular marker which tests positive in up to 80% of patients with arthritis associated with enthesitis. In contrast, it is only positive in 5%-8% of healthy people.

Other examinations are valuable, such as the erythrocyte sedimentation rate (ESR), or C-reactive protein (CRP), as these measure the degree of general inflammation. Nevertheless, diagnostic and treatment decisions tend to be based more on the clinical manifestations that appear rather than the analytical tests.

Depending on the treatment, patients may need periodic tests (such as haemograms, liver function tests, or urine tests) to check for treatment side effects and any pharmacological toxicity that may not show any symptoms. Joint inflammation is mainly assessed by clinical examination and, sometimes, using imaging studies, such as ultrasound. Periodic X-rays or magnetic resonance (MRI) scans can be helpful in assessing bone health and growth and in personalising the treatment.