A 15-year-old girl presents to her GP with painful joint swellings and tiredness. A history reveals she has had joint symptoms and morning stiffness for six months, and it has started to affect her daily life. On examination, she is afebrile and has multiple joint swellings involving both wrists, all proximal interphalangeal joints, and both ankles. She has low haemoglobin, high platelets and significantly raised inflammatory markers. The GP suspects juvenile idiopathic arthritis (JIA) and urgently refers her to a paediatric rheumatologist.
The problem
JIA is a heterogeneous group of conditions characterised by arthritis of unknown cause in children under 16 years.1 It is the most common cause of chronic arthritis in childhood with an incidence of around one in 1,000 in the UK.2 JIA is classified according to onset pattern:
- Oligoarthritis – four or fewer joints affected in first six months. May subsequently extend and follow a polyarthritic course.
- Polyarthritis – five or more joints affected in first six months. Subdivided by presence or absence of rheumatoid factor.
- Systemic arthritis – arthritis and quotidian fever, with at least one of:
– evanescent rash
– lymphadenopathy
– serositis
– hepatosplenomegaly.
- Psoriatic arthritis.
- Enthesitis-related arthritis – most frequent in boys and associated with HLA-B27.
Features
Often there is a history of morning stiffness with inflammatory joint pain, which improves as the day progresses. Joint pain that is worse at the end of the day is more likely to have a mechanical cause.
Diagnosis
There are no conclusive lab tests available and diagnosis is made on clinical grounds. JIA must be considered as a diagnosis of exclusion. A careful history and examination should aim to rule out other possible causes of musculoskeletal symptoms in childhood. Differential diagnoses include infection, trauma and non-accidental injury, malignancy, connective tissue disorders and mechanical causes.
The paediatric gait, arms, legs and spine examination should be used as a screening tool. Go to pulsetoday.co.uk/tools-and-resources to view a useful guide from Arthritis Research UK. Examine all joints for pain, tenderness, swelling or restriction, noting the number and distribution of affected joints.
Perform an overall examination looking for systemic signs such as fever, lymphadenopathy, organomegaly, rashes and nail changes – this can help differentiate between JIA subtypes.
Uveitis is associated with JIA and can be sight-threatening, so all children with JIA need regular screening from an ophthalmologist.
Management
Early referral to paediatric rheumatology is essential to limit joint damage and disability. Management will be within a multidisciplinary team including specialist nurses, physiotherapists, occupational therapists, social workers, psychologists and ophthalmologists.
Pharmacological management consists of disease-modifying antirheumatic drugs, biologic agents, and intra-articular, intravenous, or oral steroids. These may make children susceptible to infections so the patient should be monitored closely.
Dr Liza McCann is a consultant paediatric rheumatologist, Dr Naomi Cable is an SHO in rheumatology, and Dr Aruna Bhat is a specialist paediatric registrar in rheumatology, at Alder Hey Children’s Hospital, Liverpool.
Alder Hey is one of Europe’s biggest and busiest children’s hospitals providing care for over 275,000 children and young people each year. Alder Hey has a broad range of hospital and community services for direct referral from primary care. The Trust also offers more complex tertiary services – it is the designated national centre for head and face surgery and a Centre of Excellence for children with cancer, spinal and brain disease. Alder Hey has been chosen to be a national centre for heart surgery, a respiratory ECMO surgery centre and one of just four specialist centres to provide surgery for drug-resistant epilepsy. More information about Alder Hey and its services can be found at www.alderhey.nhs.uk.
References
1 Petty RE, Southwood TR, Manners P et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton. The Journal of Rheumatology 2001;31:390-2
2 Manners PJ and Bower C. Worldwide prevalence of juvenile arthritis why does it vary so much? The Journal of Rheumatology 2002;29:1520-30
