The 8-year-old female child had a history of fever, joint pain, and rashes. The symptoms were first noticed at the age of 3 and were repeated at 4 years. After a remission of 2 years, the symptoms relapsed at the age of 6. Both small and large joints were affected. She had episodes of fever and was on MTX and small doses of steroids. She had elevated inflammatory parameters and negative RF/ANA.
The two possible differential diagnoses are juvenile chronic arthritis (JCA) and rheumatic fever.  Other possibilities such as viral arthritis and hematological/lymphoproliferative disorders can be excluded, as the disease duration is around one and half years. The possibilities of benign variants of hematological disorders like thalassemia and other hemoglobinopathies are also ruled out, as her Hb% was >12 gms. Her cardiovascular examination was normal. Persisting arthritis excludes the possibility of rheumatic fever. Rarely, JCA may overlap with rheumatic fever and has been reported in the literature.
In the current case, fever should be considered the dominant symptom and polyarthritis as an additional symptom.  Both RF and ANA were negative, and rashes were present. As per the International League of Associations for Rheumatology (ILAR) classification criteria (Table 1), the patient can be classified as having juvenile idiopathic arthritis (Still's disease) with the extended polyarticular presentation. There are 3 different classification criteria for JCA put forth by the International League of Associations for Rheumatology (ILAR), the American College of Rheumatology criteria for juvenile rheumatoid arthritis (JRA), and The European League Against Rheumatism (EULAR) criteria for juvenile chronic arthritis (JCA) (Table 1, 2 and 3).1, 2, 3  In Stills disease, ferritin level is generally found to be abnormally high. The normal level noted in the current patient could be because of treatment with steroids and methotrexate.
Table 1: International League of Associations for Rheumatology (ILAR) classification of juvenile idiopathic arthritis (JIA)Â 1
JIA can be diagnosed if the age at onset is under 16 years, the disease duration is 6 weeks or greater, and other known conditions are excluded.
- Systemic arthritis is diagnosed if there is arthritis in 1 or more joints with or preceded by a fever of at least 2 weeks' duration. Signs or symptoms must have been documented daily for at least 3 days and accompanied by 1 or more of the following: evanescent rash, generalized lymphadenopathy, hepatic/splenomegaly, and serositis. (Exclusions are A, B, C, and D from the exclusion list below.)
- Oligoarthritis is diagnosed if there is arthritis affecting 1 to 4 joints during the first 6 months. Persistent oligoarthritis affects up to 4 joints throughout the disease, and extended oligoarthritis affects more than 4 joints after the first 6 months of disease. (Exclusions are A, B, C, D, and E from the exclusion list below.)
- Polyarthritis (RF-negative) is diagnosed if there is a rheumatoid factor (RF)-negative arthritis affecting 5 or more joints during the first 6 months of disease. (Exclusions are A, B, C, D, and E from the exclusion list below.)
- Polyarthritis (RF-positive) is diagnosed if there is RF-positive arthritis affecting 5 or more joints during the first 6 months of disease. Two or more RF tests (taken at least 3 months apart) are positive during the first 6 months of disease. (Exclusions are A, B, C, and E from the exclusion list below.)
- Psoriatic arthritis is diagnosed if there is arthritis and psoriasis, or arthritis and at least 2 of the following: dactylitis, nail pitting, onycholysis, and/or family history of psoriasis (in a first-degree relative). (Exclusions are B, C, D, and E from the exclusion list below.)
- Enthesitis-related arthritis is diagnosed if there is arthritis and/or enthesitis with at least 2 of the following: presence or history of sacroiliac joint tenderness with or without inflammatory lumbosacral pain; the presence of HLA B27 antigen; onset of arthritis in a male over 6 years of age; acute (symptomatic) anterior uveitis; history of ankylosing spondylitis, enthesitis-related arthritis, sacroiliitis with inflammatory bowel disease, Reiter's syndrome, or acute anterior uveitis in a first-degree relative. (Exclusions are A, D, and E from the exclusion list below.)
- Undifferentiated arthritis is diagnosed if there is arthritis that does not fulfill criteria in any of the above categories or that fulfills criteria for 2 or more of the above categories.
Exclusions
- Psoriasis or history of psoriasis in patients or first-degree relatives.
- Arthritis in HLA B27 positive males beginning after the age of 6 years.
- Ankylosing spondylitis, enthesitis-related arthritis, sacroiliitis with inflammatory bowel disease, Reiter's syndrome, acute anterior uveitis, or history of 1 of these disorders in first-degree relatives.
- Presence of IgM rheumatoid factor on at least 2 occasions at least 3 months apart.
- Presence of systemic-onset juvenile idiopathic arthritis (SoJIA) in patients.
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Table 2:Â American College of Rheumatology criteria for juvenile rheumatoid arthritis (JRA)
| JRA can be diagnosed if the age at onset is under 16 years; there is arthritis in 1 or more joints; disease duration is 6 weeks or greater; and other forms of juvenile arthritis (e.g., psoriatic and inflammatory bowel disease-associated arthritis) have been excluded.
Disease type is defined by the type of disease present in the first 6 months.
- Systemic-onset JRA is daily (quotidian) fever spiking to more than 39°C (102.2°F) for 2 weeks or greater in association with arthritis of 1 or more joints.
- Pauciarticular JRA is arthritis in 4 or fewer joints in the first 6 months of disease.
- Polyarticular JRA is arthritis in 5 or more joints in the first 6 months of disease.
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Table 3: The European League Against Rheumatism (EULAR) criteria for juvenile chronic arthritis (JCA)
| JCA can be diagnosed if the age at onset is under 16 years, there is arthritis in 1 or more joints, and the disease duration is 3 months or greater.
Diagnostic criteria for specific disease types are outlined below.
- Systemic JCA is arthritis with characteristic fever.
- Pauciarticular JCA is arthritis in fewer than 5 joints.
- Polyarticular JCA is arthritis in more than 4 joints with negative rheumatoid factor.
- Juvenile rheumatoid arthritis is arthritis in more than 4 joints with positive rheumatoid factor.
- Juvenile ankylosing spondylitis is the presence of features of ankylosing spondylitis in a child under 16 years old.
- Juvenile psoriatic arthritis is the presence of psoriatic arthritis in a child under 16 years old.
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Final diagnosis
Systemic onset JCA
Follow-up
The patient has shown symptomatic improvement and has been maintained on methotrexate and a tapering dose of steroids.
Learning points
- JCA should be classified according to the specified criteria.
- Relapse and remission may occur in JCA patients, and the remission may often spread across many months.
References
- Petty RE, Southwood TR, Manners P, Baum J, Glass DN, Goldenberg J, et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol. 2004 Feb;31(2):390–2.
- Brewer EJ, Bass J, Baum J, Cassidy JT, Fink C, Jacobs J, et al. Current proposed revision of JRA Criteria. JRA Criteria Subcommittee of the Diagnostic and Therapeutic Criteria Committee of the American Rheumatism Section of The Arthritis Foundation. Arthritis Rheum. 1977 Mar;20(2 Suppl):195–9.
- European League Against Rheumatism. EULAR Bulletin No. 4: nomenclature and classification of arthritis in children. Basel: National Zeitung AG; 197.
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