[Polycythemic chorea. Description of a clinical case].

The authors report a 69-year-old man affected by polycythaemia rubra vera since the age of sixty, who presented persistent left hemichorea of acute onset, occurring ten months before the exacerbation of the haematologic abnormalities. Previously he had been suffering from a transient episode of chorea concomitant with relapsing of polycythaemia. CT scan of the brain showed diffuse cortico-subcortical atrophy, whereas Doppler velocimetry of carotid arteries demonstrated a rise in cerebral blood flow resistance and a stenosis of the right carotid artery in its first tract. Pathogenetic mechanisms of chorea complicating polycythaemia vera are discussed and a multifactorial origin of the syndrome is suggested.