Still's disease in adults. Value of serum ferritin determination.

Patients with systemic inflammatory diseases can present with protracted fe ver or symptoms suggestive of severe infection. Investigations for an infec tion remain negative and empirical antimicrobial therapy fails to provide r elief. This scenario is encountered in adult Still's disease, a condition f or which there is no diagnostic laboratory test. Thus, the diagnosis of adu lt Still's disease is one of exclusion, Marked serum ferritin elevation str ongly suggests adult Still's disease, although it is not among current crit eria for this condition. The case of an 18-year-old who came to the emergen cy room for an "infection" is reported. The serum ferritin assay suggested adult Still's disease, and glucocorticoid therapy was dramatically effectiv e.