Fatal myocarditis in adult-onset Still disease with diffuse intravascular coagulation

Adult-onset Still disease (AOSD) is a rare condition disease of unknown etiology, characterized by quotidian or double quotidian spiking fever, with an evanescent pink-salmon rash, arthritis and multi-organ involvement. Diagnosis is usually clinical and made after other diseases in the differential diagnosis are excluded. We herein report the case of a patient with a remarkable familial autoimmune background in whom adult Still disease started off with a diffuse intravascular coagulation, probably triggered by a macrophage activation syndrome, followed by an acute interstitial myocarditis, leading to a fatal complete atrioventricular block. This case highlights that AOSD represents a troubling condition and that it may suddenly get worse with life-threatening events.