Cerebrovascular symptoms in primary thrombocytosis

Twenty-eight cases of primary thrombocytosis associated with cerebrovascular symptoms have been analyzed. Five were personally studied at the Massachusetts General Hospital, and 23 additional cases were reviewed from the literature. Ages ranged from 32 to 81. Twenty-six of the 28 had platelet counts over one million per cu. mm. Symptomatology and findings included transient ischemic attacks of paralysis of upper and lower extremities, dysphasia, dysarthria, and paresthesias of face, arms, hands and fingers. Also recorded were transient monocular blindness, retinal artery embolism, retinal venous occlusion, headache, vertigo, seizures, occlusion of carotid, basilar and middle cerebral arteries and lateral medullary syndrome. Therapy included 32P, nitrogen mustard, myleran, splenectomy, steroids, heparin, coumadin, aspirin and sulfinpyrazone. Studies of platelet aggregation undertaken in three cases showed a return toward normal with treatment. Successful reduction in platelet count prevented the transient ischemic manifestations. Platelet studies should be considered in the investigation of all cerebrovascular cases particularly when transient symptoms evade adequate explanation.