|Systemic Juvenile Idiopathic Arthritis (SJIA)|
People with Systemic Juvenile Idiopathic Arthritis (SJIA) (also known as Stills) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions.
The greatest threat to SJIA patients is that they can develop Macrophage Activation Syndrome (MAS),which is a life-threatening systemic inflammatory atttack throughout the body that can cause complications that can lead to death in some cases. In fact, MAS may be present at the onset of notable symptoms of SJIA. There are degrees of severity of SJIA, and variance in the patient's time with symptoms, and disease control. Some patients may have a single bout of systemic inflammation, then get control of their disease with treatment, and recover and become more stable, and others may still have flares of their disease, despite treatment. There are some more severe cases that have more challenges in getting more stable and under control, even with the available medications, and may be at more risk for chronic involvement and secondary complications from chronic inflammation. The good news is that there are a number of treatments for SJIA that can be tried, but more research is needed.
For more helpful insights on SJIA, please visit Kids Get Arthritis Too-About SJIA Complications
Note that with SJIA, patients often develop the sudden onset of systemic inflammation symptoms, such as fevers, rash, anemia, and other changes in labs before they present with joint involvement, which can include MAS in some cases. Systemic symptoms often start with daily high fevers, often presenting every afternoon or evening for a few weeks, and accompanied by the salmon-pink rash over the body. These symptoms can be similar to some other autoinflammatory diseases, however most other autoinfalmmatory diseases do not have daily fevers, except for a few of the more severe, chronic autoinflammatory diseases.
At this time, a specific genetic cause has not been identified for SJIA, but it is now considered to be an autoinflammatory disease that can develop more of an autoimmune component.
It is important for doctors and families to be aware of the signs of MAS. Even if a patient is on treatment, MAS can develop,and in some cases, patients on medication for SJIA may have sub-clinical lab findings, and less obvious signs of MAS that should be considered serious, and the disease managed to prevent full-blown MAS. There is a new set of diagnostic criteria, set in place by experts from EULAR and PReS that are helpful, and attention to these findings can help more patients.
2016 PReS and EULAR Classification Criteria for MAS in SJIA:
Ferritin >684 ng/ml
plus any TWO of the following:
Platelet Count ≤181 x 1,000,000,000/L
Aspartate Amminotransferase >48 units/L
Triglycerides >156 mg/dL
Fibrinogen ≤ 360 mg/dL
http://2016 2016 Classification Criteria for Macrophage Activation Syndrome Complicating Systemic Juvenile Idiopathic Arthritis
Other forms of Juvenile Idiopathic Arthritis (JIA):
The more commonly known forms of Juvenile Idiopathic Arthritis (JIA) are considered to be autoimmune diseases, and SJIA used to be considered to be more of an autoimmune disease too. But new findings indicate that Systemic JIA (SJIA)-a more rare subtype of JIA should be classified as an autoinflammatory disease instead of an autoimmune disease. Only around 10% of the US pediatric population with JIA happen to have SJIA. Systemic JIA patients show signs that there are abnormalities in the innate immune system. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2774820/
Systemic JIA patients do not have a rash at birth or the neonatal period, which can be a feature with a few other autoinflammatory diseases, such as CAPS, or NLRC4-MAS. However, the salmon-pink rash with SJIA can appear similarly to some other autoinflammatory diseases, so it is impportant for doctors to do the right lab tests to help to identify SJIA, vs other conditions.
Review the "Expert consensus on dynamics of laboratory tests for diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis." for suggested labs and symptoms to consider for SJIA.
Visit our comparative database of autoinflammatory diseases, symptoms and labs, which also features rash images for SJIA, CAPS, NLRC4-MAS and other conditions to consider.
Helpful SJIA posts on our saidsuport.org blog.
The Systemic JIA Foundation is a great resource for anyone dealing with SJIA/
The Arthritis Foundation has more information on JIA, or other autoimmune diseases