Juvenile idiopathic arthritis

Summary

Juvenile idiopathic arthritis (JIA) is defined as joint inflammation presenting in children under the age of 16 years, and persisting for at least six weeks, with other causes excluded. It is the most common cause of paediatric ,,anterior uveitis and is more likely in females. Patients primarily present with arthritis but ophthalmic symptoms occur in certain subtypes. These symptoms can cause decreased visual acuity and may progress to blindness if untreated or in treatment-resistant cases.

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Aetiology

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The cause of JIA is not well-established but individuals can sometimes be genetically predisposed depending on HLA sub-typing. Those with the predisposition are then subjected to unknown environmental triggers that cause the immune-mediated arthritis. It has a prevalence of 1:1000, with slightly more likelihood in females than males.

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Note that often anterior uveitis is associated with HLA-B27 however this is not the case in JIA.

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Clinical features

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JIA is defined as an arthritis of unknown aetiology lasting 6 or more weeks in patients younger than 16 years old.

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This is then further classified according to the International League of Associations for Rheumatology as follows:

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Ocular signs and symptoms

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Children are often initially asymptomatic and therefore screening is important to monitor any development of ocular manifestations (see below). If there is sufficient inflammation then they may complain of occasional floaters or decreased visual acuity.

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Screening is performed with a slit lamp and looks for signs of active inflammation such as aqueous flare (protein seeping from blood vessels into the anterior chamber fluid). If this is present then there is a higher risk of long-term complications, especially if present at the initial appointment.

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Long-term complications include:

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  • Cataracts
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  • Band keratopathy
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  • Secondary glaucoma
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  • Cystoid macular oedema
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  • Posterior synechiae
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There is also a higher chance of chronic rather than acute anterior uveitis (where symptoms are present for longer than 3 months). Click here to read more about the classic features of anterior uveitis.

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Patients can experience exacerbations of their JIA throughout childhood although the specific triggers for these have not yet been identified.

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Diagnosis

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Anti-nuclear antibody (ANA) is a blood test that is useful in JIA as a positive result has a higher risk of chronic anterior uveitis. Other tests such as rheumatoid factor and HLA-B27 can be useful during the differential diagnosis stage.

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Ophthalmic screening is recommended for children diagnosed with JIA, uveitis may precede diagnosis or occur very soon after diagnosis.

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  • If patients are symptomatic they should be seen within 1 week of referral to identify any cataracts or synechiae due to risk of progression to blindness.
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  • After initial consultation, the child should be seen every 2 months from the onset of symptoms for 6 months and then every 3-4 months until they reach the age of 11-12 but this is dependant on how many joints are affected and their ANA status.
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Management

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  • As the condition is inflammatory, the most effective management is topical steroids– especially for acute exacerbations.
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  • Topical administration of mydriatic agents (such as cyclopentolate). These must be used with care due to the risk of developing amblyopia in younger children when used in one eye only.
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  • Systemic steroids and NSAIDs are second-line
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  • Immunosuppresive drugs may be required in treatment resistant cases. Examples include ciclosporin, biologics and methotrexate. These drugs require special monitoring and are only prescribed by specialist ophthalmologists (often in conjunction with a paediatric rheumatologist).
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References

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  1. Denniston, Alastair K. O., and Philip I. Murray. Oxford Handbook of Ophthalmology. Fourth edition. International edition, Oxford University Press, 2018.
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  3. Hollenbach, Jill A., et al. “Juvenile Idiopathic Arthritis and HLA Class I and Class II Interactions and Age-at-Onset Effects.” Arthritis and Rheumatism, vol. 62, no. 6, June 2010, pp. 1781–91. PubMed, https://doi.org/10.1002/art.27424.
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  5. Petty, Ross E., et al. “International League of Associations for Rheumatology Classification of Juvenile Idiopathic Arthritis: Second Revision, Edmonton, 2001.” The Journal of Rheumatology, vol. 31, no. 2, Feb. 2004, pp. 390–92.
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  7. Salmon, John F., and Jack J. Kanski. Kanski’s Clinical Ophthalmology: A Systematic Approach. Ninth edition, Elsevier, 2020.
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