How does systemic juvenile rheumatoid arthritis affect someone during adulthood if it is different from adult ra?

Not the same thing: Both are collagen vascular diseases; the juvenile form hasn't had time to be as destructive but it can easily wreak havoc with other systems of the body besides the joints..

Autoinflammatory dis: Systemic jia/jra is actually an autoinflammatory disease rather than an autoimmune disease and is more similar to periodic fever syndromes than RA or jra. There's a problem with the innate immune system's triggering and control of inflammation, not a problem with mistakenly recognizing one's own proteins as foreign (like a virus). As such, Anakinra and steroids are most effective long term meds.