[White thrombus syndrome. Apropos of 4 new cases].

Four new cases of the white thrombus syndrome have been treated over the last 3 years. This is a rare but serious complication of heparin therapy, multifocal arterial thrombi developing in all three patients without signs of a hemorrhagic syndrome due to the thrombopenia. Physiopathologic mechanisms of this immunity phenomenon are discussed. The diagnosis should be evoked in all patients receiving heparin who on about the 10th day present vascular manifestations of the thrombosis type, rarely in association with a hemorrhage. Blood platelet levels are reduced to below 5000/mm3. Confirmation of diagnosis is by positive results of hematologic and immunologic tests. Treatment involves immediate cessation of heparin and administration of anti-platelet aggregation agents and anti-vitamins K or low molecular weight heparin, combined with arterial thrombectomy or prevention of pulmonary emboli.