Platelet hyperreactivity: report of a case with catastrophic arterial thrombosis in a child.

Platelet hyperreactivity is an important but under-recognized cause of idiopathic arterial thrombosis. We describe a case of arterial thrombosis in a previously healthy 12-year-old girl after minor trauma to the knee, resulting in lower extremity amputation. Family history was positive for arterial and venous thrombosis, but an extensive work-up for the usual inherited thrombophilia risk factors was negative. The patient was eventually diagnosed with platelet hyperreactivity and remains on life-long antiplatelet therapy.Consideration of platelet hyperreactivity in the evaluation of unusual arterial thrombotic events allows for targeted therapy, potential avoidance of future events, and timely screening of family members.