Adult Still's disease despite the presence of positive antinuclear antibodies.

We report the case of a 60-year-old woman who had recently been examined for fever of unknown origin and who presented to our hospital with high fever and myalgia, weakness, sore throat, and rash. The patient had a markedly elevated serum ferritin concentration of 40,000 ng/mL and positive antinuclear antibodies (ANA) with a titer of 1/200. Despite the presence of positive ANA, the patient was diagnosed as having adult Still's disease (ASD). High-dose steroid therapy resulted in a remarkable clinical improvement. Such a severe case of systemic inflammatory response syndrome, masquerading as sepsis with a positive ANA test, has not been reported previously, at least not in the last 15 years.