Idiopathic erythrocytosis, diagnosis and clinical management

By definition, idiopathic erythrocytosis (IE) applies to a group of patient s characterised by having a measured RCM above their predicted normal range (an absolute erythrocytosis) and following investigation do not have a for m of primary or secondary erythrocytosis. Patients with IE are heterogenous . The possibilities include physiological variation, 'early' polycythaemia vera (10-15% develop clear features of PV over a few years), unrecognized c ongenital erythrocytosis, unrecognized or unrecognizable secondary acquired erythrocytosis or a currently undescribed form of primary or secondary ery throcytosis. Patients are more commonly male with a median age at presentat ion of 55-60 years. Approximately half of the patients present with vascula r occlusive complications. Retrospective evidence indicates that vascular o cclusion occurs less frequently when the PCV is controlled at normal levels . Venesection is the treatment of choice to lower the PCV. As a general app roach to management, all patients with a PCV above 0.54 should be venesecte d to a PCV less than 0.45. This target PCV should also apply to patients wi th lesser degrees of raised PCV who have additional other risk factors for vascular occlusion. (C) 2001 Editions scientifiques et medicales Elsevier S AS.