Adult-Onset Still's Disease: Is This Truly a Diagnosis of Exclusion?

Adult-onset Still's Disease is a rare, idiopathic, inflammatory disorder characterized by arthralgia, evanescent, salmon-colored rash, and daily fevers as well as lymphadenopathy, pharyngitis, splenomegaly, myalgias, and serositis. The inciting etiology of this syndrome is unknown, though it has been hypothesized that infection triggers an autoimmune response. The Yamaguchi Criteria, the most sensitive and widely used diagnostic criteria, requires both a minimum set of criteria to be met as well other potential etiologies to be excluded. By definition, evidence of concomitant infection, malignancy, vasculitis, or connective tissue disease precludes the diagnosis of Adult-onset Still's Disease from being made. We present a very rare case of a patient who met all diagnostic criteria for Adult-onset Still's Disease, had a protracted course refractory to numerous immunosuppressant treatments, and also had evidence of coxsackie B infection with fourfold rise in viral titers on two occasions (both associated with disease flare). Although coxsackie B virus has been linked to Adult-onset Still's Disease at disease presentation, this case is unique in its protracted course and serological evidence of infection temporally related to disease flare. While accepted diagnostic criteria call for this disease to be a diagnosis of exclusion, our case supports the fact that ongoing infection may in fact be an important antigenic driver in persistent and refractory Adult-onset Still's Disease.