Adult onset Still's disease flared with pericardial effusion.

Adult onset Still's disease (AOSD) is characterized by spiking fevers, arthritis, rash, and involvement of multiple organs, and can be classified as self-limited, intermittent, and chronic disease groups. Cardiac manifestations include pericarditis and myocarditis. The case of this disease flared only with pericardial effusion is not reported. We describe a patient with adult onset Still's disease who was flared with pericardial effusion without other AOSD-associated symptoms, and propose that pericardial effusion should be included as a feature of flare in the intermittent disease group of adult onset Still's disease.