SYSTEMIC JUVENILE IDIOPATHIC ARTHRITIS & ADULT STILL'S DISEASE

[Guest guest]

[2003] [sP0026] SYSTEMIC JUVENILE IDIOPATHIC ARTHRITIS AND ADULT STILL'S

DISEASE

P. Dolezalova 1 1Department of Paediatric Rheumatology, Great Ormond Street

Hospital for Children NHS Trust, London, United Kingdom

Disease definition. Systemic Juvenile Idiopathic Arthritis (sJIA), also

known as Still's disease, is defined as chronic arthritis with or preceded

by daily quotidian fever and accompanied by one or more of the following:

rash, generalised lymphadenopathy, hepatosplenomegaly and serositis.

Epidemiology. Within the annual incidence range of all JIA (2.6-13.9

cases/100 000 children under 16 years) sJIA accounts for approximately 15%

of cases. It affects boys and girls equally. The mean age at onset is 4-6

years. 75% of reported adult cases start between 16 and 35 years of age with

slight female preponderance.

Etiopathogenesis. Although etiology of sJIA is poorly understood there is

increasing evidence for the role of various cytokines and their regulatory

pathways in disease pathogenesis. Among these expression of IL-6, TNF-alfa

and IL-10 seems to be of major importance. Several genetic polymorphisms

have been detected and their responsibility for excessive production of IL-6

and TNF-alfa discussed. Other gene polymorphisms may be involved in the

complications as amyloid-P component gene or genes involved in perforin

expression (macrophage-activation syndrome, MAS).

Clinical presentation. Spiking quotidian fever of at least 2 weeks' duration

is essential diagnostic feature. Pink evanescent rash erupting during the

fever spikes usually disappears with temperature decline. Striking

improvement of general condition between the spikes is typical.

Hepatosplenomegaly and lymph node enlargement are variably present.

Pericarditis is the most common serositis.

Arthritis often develops during the initial weeks of systemic disease but

is sometimes delayed. Its pattern can be oligoarticular at onset but

evolution

into rapidly erosive polyarthritis is common. The main laboratory features

include increased non-specific inflammatory markers. Autoantibodies are

often absent.

Main disease-related, life-threatening complications include amyloidosis

and MAS, with latter being described also as a presenting manifestation.

Growth and developmental delay, malnutrition and osteopenia are common

features of long-standing disease.

Differential diagnosis. Exclusion of malignancies and systemic infections is

of vital importance. These include acute lymphoblastic leukemia, lymphoma

and neuroblastoma. Osteomyelitis, subacute bacterial endocarditis,

mycobacterial and viral infections may share some clinical features of sJIA.

Other systemic inflammatory disorders to be distinguished include SLE,

dermatomyositis, systemic vasculitis as well as rare entities of

sarcoidosis, CINCA and recurrent fever syndromes.

Management. Complex approach including pharmacotherapy, physiotherapy,

psychosocial support and disease education is essential. Various drug

combinations are tailored individually depending on disease severity and

estimation of prognostic factors. NSAIDs are commonly prescribed for fever

and pain control. Corticosteroids are often needed for severe systemic as

well as articular manifestations. Weekly parenteral methotrexate (MTX) is

started early in the disease course for joint disease. Novel therapies

include biologic modifiers of inflammatory response targeting TNF-alfa and

IL-6. Long-term efficacy and safety of Etanercept has been reported in JIA

and in open-label trial also in adult patients. Use of anti-IL-6 receptor

monoclonal antibody (MRA) has been reported in adult-onset disease and its

use in children is under investigation. Less commonly used drugs often

combined with MTX include cyclosporin, high-dose IVIG and cyclophosphamide.

Chlorambucil has been successfully used for amyloidosis. Thalidomide is of

potential benefit in resistant disease. Autologous stem cell transplantation

is reserved for selected patients refractory to other treatment options.

Other therapies include mainly prevention and treatment of osteopenia and

growth delay.

Course of the disease, outcome and prognosis. Monocyclic disease course with

complete remission in 2-3 years has the most favourable prognosis. Over 50%

of patients have prolonged active disease either of intermittent or

persistent character. Various prognostic factors have been evaluated in

order to identify patients at high risk. Early predictors include presence

of generalised lymphadenopathy, age under 8 years and polyarticular

involvement at disease onset, polyarticular disease, hip involvement,

presence of active systemic disease and thrombocytosis at 6 months from

disease onset. Severity of long-term disability correlated with cumulative

duration of active disease periods. Mortality rate is higher than in other

JIA subtypes. Major causes of death include amyloidosis with renal failure,

infection, MAS and myopericarditis.

Juvenile arthritis: What is the difference from adult arthritis?