The management of thrombocytosis

General considerations on thrombokinetics Thrombocytopenia and thrombocytosisSince the work of James Homer Wright more than 80 years ago (l), it has been universally accepted that blood platelets are produced by the megakaryocytes and constitute anucleate fragments of the cytoplasm of these giant cells.Non-activated platelets circulate as discoidal cells 2-3 pm in diameter, and most clinicians would agree that the normal human peripheral platelet count should range from 150-350 x 109/l.It is proposed that a thrombocytopenic state is present if the platelet count is below 100 x 109/l.Conversely, the term thrombocytosis implies that the peripheral platelet count is greater than 400 x 109/l. Platelet survivalBy using various isotopes for platelet labelling, the mean life-span of circulating platelets in the normal human has been estimated to average 7-9 days (2-5).There is evidence that platelet survival decreases slightly with age (3, 6).More pronounced acceleration of peripheral platelet destruction is recorded in a variety of clinical conditions, e.g.splenomegalic states, atherosclerotic disease, thrombosis, acute myocardial infarction, fever, septicemia and widespread neoplasia (6-9).Dramatic shortening in platelet survival is characteristically seen in immune thrombocytopenia (10-12).