[Antithrombin III deficiency induced by heparin and constitutional protein C deficiency. Apropos of a case].

Major mesenteric venous thrombosis in a young man who had already had spontaneous thromboembolic accidents prompted the diagnosis in 1982 of 'Antithromin III' deficiency. The initial reduction of this inhibitor proved to be secondary to a consumption raised abnormally by Heparin. Research into the family antecedents made it possible in 1983 to discover a constitutional 'Protein C' deficiency without stopping the antivitamins K for this patient.