• essential thrombocytosis;
  • neurological

Objective– To evaluate the prevalence of neurological abnormalities in patients with ET and attempt to identify risk factors for neurological complications. Method– Ninety-five patient charts were reviewed from January 1983–July 1999. Seventy patients fulfilled the Polycythemia Vera Study Group criteria for diagnosing ET. Results– Eighteen patients (25.7%) had episodes of neurological impairment, 52 (74.3%) had none. Neurological features – occlusive cerebrovascular event – 9; chronic headache – 3 and dizziness – 3, mononeuritis multiplex, sinus vein thrombosis and epilepsy – 1 each. The interval between diagnosis of ET and occurrence of neurological events ranged from time of presentation (10 patients) to 13 years (1 patient) with a high predominance of females, 88.8% and 55%, respectively. Conclusions– Neurological complications occurred at presentation or during follow-up in approximately 25% of patients with ET. Our observation suggests that further investigation focusing on the possible mechanisms for neurological deficits in females with ET should be considered.