[Dangerous thrombocytopenia in thrombolytic therapy of venous thrombosis of the leg].

Two days after 5 days heparin treatment of a superficial thrombophlebitis a 45 year old woman was admitted to hospital with an extended phlebothrombosis of a leg. Before starting thrombolytic treatment a bolus of 5000 U heparin followed by 1000 U/h was administered. During thrombolytic treatment with ultrahigh streptokinase the platelet count dropped from 172,000/microliter to 73,000 and 29,000/microliter. Thrombocytopenia was considered not to be a complication of thrombolytic therapy but by demonstrating heparin induced platelet antibodies to be due to a heparin-associated thrombocytopenia type II (HAT Type II).