Neurological complications of essential thrombocytosis (ET)

Objective - To evaluate the prevalence of neurological abnormalities in pat ients with ET and attempt to identify risk factors for neurological complic ations. Method - Ninety five patient charts were reviewed from January 1983 -July 1999. Seventy patients fulfilled the Polycythemia Vera Study Group cr iteria for diagnosing ET. Results - Eighteen patients (25.7%) had episodes of neurological impairment, 52 (74.3%) had none. Neurological features - oc clusive cerebrovascular event - 9; chronic headache - 3 and dizziness - 3, mononeuritis multiplex, sinus vein thrombosis and epilepsy - 1 each. The in terval 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 - Neurol ogical complications occurred at presentation or during follow-up in approx imately 25% of patients with ET. Our observation suggests that further inve stigation focusing on the possible mechanisms for neurological deficits in females with ET should be considered.