Background Pericardial tamponade and myocarditis are very seldom complication of adult onset Still’s disease and exceptionally revealed the disease. A18-year- old man was hospitalised for fever, polyartharalgia, dyspnea and thoracic pain. Chest radiograph demonstrated large cardiac sillouette. The electrocardiogram showed tachycardia and non specific diffuse ST-T changes.

Echocardiography revealed a mild alteration of left ventricular function and circumferential pericardial effusion with diastolic collapse. A pericardiocentesis yielded 300 ml of sersanguinos fluid. The white blood cell count was 41200 with 96% neutophils. An extensive evaluation for infection was unrevealing and tests for antinuclear factors and rheumtoid factor were negative. Still’s disease was diagnosed. The patient was treated with prednisone 1 mg/kg/day and rapidly improved.