Juvenile Idiopathic Arthritis

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Juvenile Idiopathic Arthritis
Classification and external resources
DiseasesDB 7052


Disease Entity

Disease

Juvenile idiopathic arthritis is a type of athritic joint disease that presents in patients under age 16 and has no definable cause, and can be associated with inflammation in the uveal tract of the eye. Other names for the entity include juvenile rheumatic arthritis and juvenile chronic arthritis. This is the most common cause of uveitis in children.

JIAis defined as ‘arthritis beginning before age 16 and lasting for at least 6 weeks’ and all other differential diagnoses should have been excluded. 

JIA has three types of onset with varying risks for uveitis. The oligoarticular or pauciarticular onset, which is the most common form, has the highest risk for uveal involvement. Polyarticular onset has an intermediate risk, and systemic onset JIA has a low risk for associated uveitis.

Etiology

The cause of inflammation (including that of the uveal tract) in this disease is not yet known. It is likely an immune reaction to unidentified ocular antigens, and JIA may be a genetic disease.

Risk Factors

Risk factors for JIA have not been established. However, male children have been found to have a worse visual prognosis from JIA-associated uveitis. Also, worse visual outcomes have been noted when uveitis is diagnosed before arthritis. Certain blood markers, particularly anti-nuclear antibody, human leukocyte antigen DR5 (HLA-DR5) and human leukocyte antigen DR1 (HLA-DR1) can predict the general risk for developing uveitis related to JIA, and will be discussed further below.

General Pathology

JIA is an autoimmune disease. Uveitis related to this condition is presumed to be a reaction of the body against various proteins in the eye. This leads to inflammation in the eye.

Pathophysiology

As an idiopathic disease, the cause of JIA remains to be elucidated.

Primary prevention

There is no way to prevent uveitis related to JIA, but early and regular examination by the an ophthalmologist, and particularly a uveitis-specialist, is warranted.

Diagnosis

History

Patients are usually asymptomatic children (ANA/anti+ve females) and the ocular disease is often detected late with complications including band-shaped keratopathy, cataract, squint, and glaucoma. Rarely patients may have mild symptoms of uveitis, including sensitivity to light, blurry vision, pain and rarely red eye. The male patients HLA-B27 +ve patients may have severe inflammation, redness, pain, and hypopyon as seen in association with HLA-B27. These patients are usually older.

Since many patients have no or few symptoms, patients diagnosed with juvenile idiopathic arthritis should have examinations to detect early or low-grade uveitis.

Patients with pauciarticular or oligoarticular JIA have a great risk for developing uveitis. Patients with systemic JIA have a lower risk. Therefore, the history of the arthritis symptoms, including the number of joints involved, is an important part of the history.

The age at onset of arthritic symptoms is also useful to know as younger patient have a higher risk of developing uveitis.

Other ocular symptoms as well as a list of medications are important information for the physician.

Physical examination

In addition to joint examination, a full ocular examination is indicated. The eye is typically white without symptoms.

Visual acuity may or may not be affected, and the patient's intraocular pressure can be high, normal or low. Examination at the slit lamp will mostly likely show no or minimal redness of the conjunctiva and sclera. The cornea may show band keratopathy, a deposition of calcium across the center of the cornea. The iris may form sticky connections to the lens or to the cornea, forming posterior or peripheral anterior synechiae, respectively. Some patients may develop cataracts, usually at the back of the lens in the posterior subcapsular location. The main finding is in the anterior chamber. Inflammatory cells and proteins (flare) will be present in this chamber, and keratic prepcipitates, which are depositions of inflammatory blood cells, may form. In nearly 80% of patients, both eyes are affected.

Examination of the retina on dilated fundus examination can be normal or show signs of inflammation. There may be inflammatory cells and proteins in the vitreous. The macula, the part of the retina responsible for central vision, may become swollen (macular edema). This is termed cystoid macular edema. The pressure inside the eye may become low and cause wrinkles in the macula, which is known as hypotony maculopathy.

Type Definition % of JIA Types Comments
Pauciarticular/oligoarticular onset <=4 joints involved in first 6 months 40-50% Consists of 80-90% of JIA-assocaited uveitis.

Type 1- female, ANA+, <5 year age

Type 2- Male, HLA-B27+ (in 75%), older, may develop seronegative spondyloarthropathy later

Chronic anterior uveitis may be seen in 25% cases of type 1.

In type 2- acute aggressive anterior uveitis may be seen, sometimes with fibrin and hypopyon, like that is seen in HLA-B27 +ve anterior uveitis in adults. This acute uveitis may be recurrent.

Polyarticular onset >4 joint involved in first 6 months 40% Consists of 10% of JIA-associated uveitis.

Patients with rheumatoid factor may not develop uveitis.

Systemic onset/Still disease fever, hepatosplenomegaly, rash, lymphadenopathy, with or without joint involvement 10-15% <6% patients have uveitis.

Uveitis is rare.

Signs

As mentioned in the physical exam, the signs of JIA-related uveitis are mainly inflammatory cells in the anterior chamber, though corneal clouding, cataracts, inflammation of the vitreous and macular changes may be found.

Symptoms

Patients are most often asymptomatic and their eyes are not red. If the patients have symptoms, they are usually related to uveitis, including light sensitivity and blurry vision.

Clinical diagnosis

The diagnosis of uveitis related to JIA is made clinically, with the ophthalmologist finding signs of inflammation in the eye of a patient with joint symptoms consistent with JIA. Slit lamp examination is crucial to document activity of the inflammation.

Diagnostic procedures

There is no procedure or lab test that can confirm the diagnosis of uveitis related to JIA.

Laboratory test

There are several blood markers that can help predict the likelihood of developing uveitis after a diagnosis of JIA, and to rule out other diagnosis.

Antinuclear antibody/ANA

The antinuclear antibody test looks for antibodies that react against nuclei in human tissue. Over 80% of patients with JIA related uveitis are positive for this test. Therefore, if a patient diagnosed with JIA has a negative ANA test, there may be a lower risk of developing uveitis. Young female JIA patients with a positive ANA have a very high risk for developing uveitis.

Human leukocyte antigens

Human leukocyte antigens are proteins expressed on human blood cells. These proteins can act as markers for certain disease.

Human leukocyte antigen B27 (HLA-B27)- HLA-B27 is a marker for seronegative spondyloarthropathies, which can also cause uveitis in young patients. In patients with JIA, positive HLA-B27 testing is found in those with spinal involvement and in older boys who are ANA negative and rheumatoid factor negative. These boys are at high risk for developing uveitis.

Human leukocyte antigen DR5 (HLA-DR5) and DR1 (HLA-DR1)

In the pauciarticular form of the disease, having a positive anti-nuclear antibody (ANA) test and human leukocyte antigen DR5 (HLA-DR5) test puts patients at increased risk for developing uveitis. Such patients should be evaluated by an ophthalmologist every six months for seven years.

If a patient has a positive ANA and HLA-DR5 tests, and the patient also had arthritis before age seven and has the disease for less than 4 years, he or she is at a very high risk for developing eye disease should be evaluated every three months for seven years.

If the patient is negative for ANA and HLA-DR5, and also positive for human leukocyte antigen DR1 (HLA-DR1), he or she should be evaluated once every 12 months for seven years (2).

Differential diagnosis

Uveitis may be related to other causes, including

Management

General treatment

The symtpoms of uveitis are treated with medicines. Related complications like band keratopathy and cataracts are managed surgically.

Medical therapy

Treatment begins with corticosteroids to combat inflammation, but approximately 20% of patients will not respond. If there is severe or chronic disease, non-steroidal anti-inflammatory drugs (NSAIDS) may be used to prevent macular edema. If both eyes are involved, it may be beneficial to use systemic corticosteroids.

If there is little response to steroids or severe side effects, systemic immunomodulatory agents may be used.

Medical follow up

Based on the risk of developing uveitis and the current status of the disease, the patient should be seen by an ophthalmologist every 3 months to one year for regular check-ups, and more often if deemed necessary.

Surgery

Surgery may be required for removal of cataracts, for glaucoma or to treat band keratopathy.

For cataract surgery- the implantation of intraocular lens (IOL) is controversial in JIA as most of the cases form posterior capsular opacity, posterior synechia, or inflammatory deposits over the IOL which may be visually significant. The eye may be left aphakic with contact lens postoperatively.

The Band-shaped keratopathy may need repeated chelation with EDTA if it is visually significant.

Glaucoma may not respond to anti-glaucoma drops and may need trabeculectomy of a glaucoma drainage device.

Surgical follow up

Regular surgical follow as indicated for the procedure peformed...

Prognosis

Currently, approximately 12% of patients with pauciarticular-onset JIA go blind, usually due to the effects of chronic low grade inflammation (1).

Additional Resources

References

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