What is the clinical course and prognosis of Stills disease?
The course of illness generally follows one of three patterns, with approximately one-third of patients following each: self-limited illness, intermittent flares of disease activity, or chronic Still’s disease. The patients who experience a self-limited course undergo remission within 6 to 9 months. Of those with intermittent flares, two-thirds will only have one recurrence, occurring from 10 to 136 months after the original illness. A minority of patients in this group will experience multiple flares, with up to 10 flares being reported at intervals of 3 to 48 months. The recurrent episodes are generally milder than the original illness and respond to lower doses of medications. In the group that experiences a chronic course, arthritis and loss of joint range of motion become the most problematic manifestations and may result in the need for joint arthroplasty, especially of the hip. The systemic manifestations tend to become less severe.
The presence of polyarthritis or large-joint (shoulder, hip) involvement and an elevated ferritin level at onset are poor prognostic signs associated with the development of chronic disease. A high fever >39.5°C is predictive of monocyclic AOSD. The 5-year survival rate in AOSD is 90% to 95%. Deaths occurring in Still’s disease have been attributed to infections, liver failure, amyloidosis (2%–4%), adult respiratory distress syndrome, heart failure, status epilepticus, and hematologic manifestations including DIC, TTP, and MAS/RHL.
