Systemic juvenile idiopathic arthritis

A subtype of juvenile idiopathic arthritis characterized by systemic inflammation

Systemic juvenile idiopathic arthritis
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Synonyms	Still's disease
Pronounce	N/A
Specialty	N/A
Symptoms	Fever, rash, arthritis, lymphadenopathy, hepatosplenomegaly
Complications	Macrophage activation syndrome
Onset	Childhood
Duration	Chronic
Types	N/A
Causes	Unknown
Risks	N/A
Diagnosis	Clinical evaluation, laboratory tests
Differential diagnosis	N/A
Prevention	N/A
Treatment	NSAIDs, corticosteroids, DMARDs, biologics
Medication	N/A
Prognosis	Variable
Frequency	Rare
Deaths	N/A

Systemic juvenile idiopathic arthritis (sJIA), also known as Still's disease, is a subtype of juvenile idiopathic arthritis (JIA) that is characterized by systemic inflammation affecting the entire body. Unlike other forms of JIA, sJIA presents with systemic symptoms such as fever and rash, in addition to arthritis.

Clinical Presentation

Systemic juvenile idiopathic arthritis typically presents in children under the age of 16. The hallmark symptoms include:

• Fever: High, spiking fevers that often occur once or twice daily, usually in the evening.
• Rash: A salmon-pink maculopapular rash that may appear with fever spikes.
• Arthritis: Joint inflammation that can affect any joint, leading to pain and swelling.
• Lymphadenopathy: Swollen lymph nodes.
• Hepatosplenomegaly: Enlargement of the liver and spleen.

Pathophysiology

The exact cause of systemic juvenile idiopathic arthritis is unknown, but it is believed to involve a combination of genetic and environmental factors. The disease is characterized by an overactive immune response, leading to widespread inflammation. Cytokines such as interleukin-1 (IL-1) and interleukin-6 (IL-6) play a significant role in the inflammatory process.

Diagnosis

Diagnosis of sJIA is primarily clinical, based on the characteristic symptoms and exclusion of other conditions. Laboratory tests may show elevated inflammatory markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Other tests may include:

• Complete blood count (CBC): May show anemia and leukocytosis.
• Ferritin levels: Often elevated in sJIA.
• Antinuclear antibody (ANA) and rheumatoid factor (RF): Typically negative in sJIA.

Treatment

Treatment of systemic juvenile idiopathic arthritis aims to control inflammation, relieve symptoms, and prevent joint damage. Options include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs): For pain and inflammation.
• Corticosteroids: For severe inflammation.
• Disease-modifying antirheumatic drugs (DMARDs): Such as methotrexate.
• Biologic agents: Targeting specific cytokines, such as IL-1 inhibitors (anakinra) and IL-6 inhibitors (tocilizumab).

Prognosis

The prognosis of sJIA varies. Some children experience remission, while others may have chronic arthritis or complications such as macrophage activation syndrome (MAS), a potentially life-threatening condition.

Also see

• Juvenile idiopathic arthritis
• Macrophage activation syndrome
• Rheumatology
• Autoimmune disease