[Rare etiology of hemiplegia with young adult: paradoxical embolism (author's transl)].

Paradoxical embolism is due to the passage of an embolic material from the deep veins of the lower extremities or pelvis, into the systemic circulation through an abnormal intracardiac communication. Only the angiographic and hemodynamic diagnosis practised on two young patients with a cerebral embolism, can explain the mechanism. The diagnosis is based on the arterial embolism, the venous thrombosis with or without pulmonary embolism, the abnormal communication favoring right-to-left shunting. The rising of right atrial pressures permits this shunting. This high pressure can result from a pulmonary embolism, a high blood pressue due to an effort, or an embolism that might coil up over the tricuspid valve.