viernes, 22 de febrero de 2019

Juvenile Rheumatoid Arthritis

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

Usually arthritis is a disease affecting the elderly and the middle aged. Juvenile arthritis includes several types of arthritis including spondyloarthropathies and reactive arthritis that affects children and adolescents.

Who does juvenile rheumatoid arthritis affect?

Juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA), has some distinctive features that include:-

The disease affects the patient early - commonly during childhood or adolescence
The disease is more prevalent among females

JRA affects children under 16 years of age commonly and the prevalence of this condition is 0.01% in the general population.

Types of juvenile rheumatoid arthritis

There are three different types of JRA that include:-

Pauciarticular JRA

In this type of JRA four or fewer joints are involved and this type accounts for nearly half of all the cases of JRA.

The patients are usually very young girls aged between 1 and 4 years or are older boys. Both young boys and older girls, however, may also be affected.

Children with the condition may develop associated eye disorders including chronic uveitis that affects the anterior chamber of the eyes. This may cause permanent damage to the eye. Uveitis eventually affects up to 20% of children with this condition. There may be minimal symptoms with pauciarticular JRA.

Polyarticular onset JRA

In this type of JRA five or more joints are involved. This occurs in nearly 40% of all children with JRA. Apart from joint involvement there are symptoms like irritability, fatigue, anemia, loss of appetite, growth retardation etc.

This condition affects girls more often than boys. There is a later onset and chances of a positive result with Rheumatoid factor.

Systemic onset JRA

This is a less frequently seen type of JRA seen in around 10% of the JRA population. Initially there are symptoms like once daily or twice-daily fever spikes along with a characteristic pale pink rash commonly seen over the trunk and upper arms and thighs. The fever is usually low in the morning and must be present for a minimum of two weeks for diagnosis.

The children with the condition may have other systemic symptoms affecting other vital organs including hepatosplenomegaly (enlargement of the liver and spleen), lymphadenopathy (enlargement of the lymph nodes), and pericarditis (accumulation of fluid within the coverings around the heart). This condition affects both boys and girls similarly and the peak age of detection is usually between one and six years.

Diagnosis of JRA

The diagnosis is based on clinical history and family history of similar conditions as well as examination of the patient. Since falls and injuries are common among children, the initial pain and stiffness may be overlooked.

Joint pain alone, in the absence of any swelling, stiffness, tenderness, etc. however, is never sufficient to establish a diagnosis of JRA. The symptoms need to be present for at least six consecutive weeks for more confirmatory diagnosis.

JRA is diagnosed on a more confirmed basis when other conditions that may cause joint symptoms have been excluded, these include fibromyalgia, infection of the joint (septic arthritis) or leukemias etc.

The antinuclear antibody (ANA) test can be of value when clinical findings strongly suggest JRA. ANA is positive in 60% to 80% of JRA patients especially in pauciarticular JRA.

Rheumatoid factor is positive in only 15% to 20% of children with JRA. It is more frequently seen in children with later onset polyarthritis or polyarticular JRA.

In around half of the patients with JRA, the disease persists into adulthood. In over one third of the patients the disease leads to severe disability around a decade after diagnosis. Blindness due to uveitis is seen in around 15 to 305 cases.

Aims of treatment

There are two main aims of treatment:-

to relieve the symptoms of the disease
to prevent disease progression and joint damage

Easing symptoms of JRA

To ease the symptoms pain relievers and anti-inflammatory agents are the primary mode of therapy.

Non-steroidal anti-inflammatory drugs (NSAIDs) are the drugs used widely to control symptoms of JRA. They cause both pain and inflammation reduction. However, the dose required for an anti-inflammatory effect is up to twice the dose needed for pain control.

Over years NSAIDs have been replaced by other more effective agents in reducing joint inflammation. This is because of their adverse side effect profiles. NSAIDs are notorious for causing gastric ulcers, gastrointestinal complications, kidney damage and heart disease. These agents however may be administered over short term.

Preventing the progression of joint damage

To prevent progression of joint damage Disease-modifying anti-rheumatic drugs or DMARDs are widely used. These agents have a varied mechanism of action and they act by reducing joint swelling and pain, decreasing markers of acute inflammation in blood and halting the progressive joint damage.

DMARDs include Methotrexate, Sulfasalazine, Leflunomide, Hydroxychloroquine, Gold salts and Ciclosporin. DMARDs however are also associated with a varying degree of side effects.

Oral corticosteroids

In cases of severe polyarticular JRA, oral corticosteroids are sometimes used while waiting for DMARD therapy to take effect. In systemic JRA, oral steroids are often used for control of other symptoms. In all three types of JRA corticosteroids can be used as injections given directly into the joint space.

Biological agents

A newer approach is to use biological agents. TNF inhibitors were the first licensed biological agents including etanercept, infliximab, adalimumab and certolizumab. This was followed by monoclonal antibodies like abatacept, rituximab, and tocilizumab.

Supportive treatment

Supportive treatment includes exercise, joint protection, psychological support for the patient and family to help deal with the associated symptoms and disability.

Physiotherapy is an important part of therapy of debilitating arthritis. This helps maintain optimum joint flexibility and strength. Assistive devices, such as a cane, walker, long shoehorn etc. may help.