pediatrics
Perinatal Polycythemia and Hyperviscosity Syndrome
Etiology
 Dehydration in Children causing relative hemoconcentration and an elevated hematocrit mimics polycythemia, but red blood cell mass is not increased. Causes of true polycythemia include intrauterine hypoxia, perinatal asphyxia, placental transfusion (including twin-to-twin transfusion), some congenital abnormalities (eg, cyanotic Overview of Congenital Cardiovascular Anomalies , Preterm Infants rarely develop hyperviscosity syndrome. 