Myocarditis as the Initial Presentation of a Refractory Adult-Onset Still's Disease.

We present a case of adult-onset Still's disease, a rare disease that presented with a rare complication, myocarditis. After initial therapy with prednisolone 1 mg/kg/day, the patient experienced dyspnea due to severe pleural effusion and palpitations on account of new-onset supraventricular tachycardia. Therapy with three consecutive pulses of 1000 mg of methylprednisolone and anakinra 100 mg/day proved to be effective, with a progressive resolution of all symptoms. However, at three months follow-up, oligoarthritis recurred along with high serum ferritin. Secondary failure to anakinra was assumed, and a switch to tocilizumab 162 mg was made. Nevertheless, arthralgia of the wrists and knees as well as high serum ferritin still persisted after two months of therapy. Chronic disease was assumed, and the patient switched to canakinumab 4 mg/kg/dose q4week, and a complete resolution of symptoms occurred with normalization of inflammation markers. Follow-up cardiac magnetic resonance showed a complete resolution of heart involvement.