[Myopericarditis as the presenting manifestation of adult Still's disease].

INTRODUCTION: Adult Still's disease may present with multiple non-specific clinical manifestations leading to diagnostic difficulties. Presentation as initial myopericarditis is rare but must be known.

CASE REPORT: We report a 49-year-old man who presented with the sudden onset of a high fever, arthralgia and myalgia, skin rash, dyspnea and chest pain related to a myopericarditis. Infectious, neoplastic and autoimmune diagnostic work-up was non-contributive. Adult Still's disease was discussed and confirmed by the decrease in the glycosylated fraction of ferritin. Corticosteroids followed by interleukin-1 receptor antagonist (anakinra) therapy allowed a rapid improvement in clinical and biological manifestations.

CONCLUSION: Adult Still's disease should be considered in any systemic inflammatory disease without a diagnosis, even with atypical manifestations, especially since it can be life-threatening in the absence of treatment.