Differential diagnosis and management of polycythemia
Section snippets
Defining polycythemia and hyperviscosity
The terms neonatal polycythemia and hyperviscosity are often used interchangeably. Though this is not accurate, it represents an understandable simplification. In many cases, infants who have hyperviscosity are polycythemic, and vice versa [1], [2]. Nonetheless, polycythemia refers to an abnormal increase in red cell mass (hematocrit), whereas hyperviscosity refers to an increase in the internal friction of blood or the force required to achieve flow. The viscosity of whole blood is affected by
Polycythemia
The multiplicity of definitions used in the literature to define polycythemia has complicated the discussion of the incidence and outcome of this condition. The most widely accepted definition is a venous hematocrit of 65% or greater. Still, variability in sampling site, timing, and technique determine the incidence and perhaps the outcome of infants who have polycythemia/hyperviscosity. Studies have suggested that the hematocrit at term will rise from cord blood levels to a peak at 2 hours of
Incidence of neonatal polycythemia and hyperviscosity
The incidence of neonatal polycythemia and hyperviscosity ranges from 1% to 5% in the total newborn population (Table 2) [1], [13], [14], [15], [16], [17]. It is also influenced by birth weight, gestational age, and altitude. Infants who are small or large for gestational age and infants born at high altitudes have a higher incidence of polycythemia. Premature infants, especially those born after less than 34 weeks' gestation, rarely have polycythemia or hyperviscosity.
Conditions that predispose to the development of neonatal polychythemia
Erythropoiesis in the human fetus is acclimated to the relatively hypoxic fetal environment. Compared with older infants and children, fetal hematocrit is elevated and allows for an increased oxygen carrying capacity. Factors that interfere with placental oxygen concentration may increase fetal hematocrit even further, resulting in a pathologically high neonatal red cell mass. Examples include high altitude [1], maternal diabetes [18], hypertension [19], intrauterine growth retardation [20],
Clinical features and complications
Infants who have polycythemia often show increased whole blood viscosity. As the hematocrit rises above 65%, there may be an increased tendency for diminished blood flow, especially in the cerebral, hepatic, renal, and mesenteric microcirculations. Clinical symptoms may include lethargy, cyanosis, respiratory distress, jitteriness, hypotonia, feeding intolerance, hypoglycemia, and hyperbilirubinemia. Symptoms are outlined in Box 2. Several organ systems may be involved.
Treatment
Treatment of neonatal polycythemia and hyperviscosity remains controversial. Although partial exchange transfusion is recommended for symptomatic infants, outcome data do not show clear long-term benefits. Undoubtedly, infants who have clinical manifestations should receive care aimed at alleviating their symptoms. The debate lies in whether this care should involve symptomatic therapy or routine partial exchange transfusion (PET) to replace the infant's blood with a plasma substitute.
Prognosis
The diversity of follow-up data on neonatal polycythemia suggests that the outcome of these infants is variable. In part, this may result from other associated conditions, the severity of these conditions, and their underlying etiology. Still, the diagnosis of polycythemia raises many questions and concerns. For example, which infants will develop symptoms, how should they be treated, and what care will improve their short- and long-term outcomes? Polycythemia/hyperviscosity is an intriguing
References (92)
- et al.
Diagnostic errors in neonatal polycythemia based on method of hematocrit determination
J Pediatr
(1989) - et al.
Hyperviscosity in the neonate
J Pediatr
(1973) - et al.
Incidence of neonatal hyperviscosity at sea level
J Pediatr
(1980) - et al.
Partial plasma exchange transfusion improves cerebral hemodynamics in symptomatic neonatal polycythemia
Am J Med Sci
(1986) - et al.
Neonatal polycythemia
J Pediatr Health Care
(2002) - et al.
Long-term propranolol therapy in pregnancy: maternal and fetal outcome
Am J Obstet Gynecol
(1979) - et al.
Iron deficiency of liver, heart, and brain in newborn infants of diabetic mothers
J Pediatr
(1992) Current best evidence: a review of the literature on umbilical cord clamping
J Midwifery Womens Health
(2001)- et al.
Severe neonatal polycythemia after third stage of labour underwater
Lancet
(1997) Neonatal polycythemia and hyperviscosity
Clin Perinatol
(1995)
Asymptomatic syndrome of polycythemic hyperviscosity: effect of partial plasma exchange transfusion
J Pediatr
The management of polycythaemia in the newborn infant
Early Hum Dev
Normal coagulation findings, thrombocytopenia and peripheral hemoconcentration in neonatal polycythemia
J Pediatr
Nucleated red blood cells in polycythemic infants
Am J Obstet Gynecol
Left ventricular function in normal newborn infants and asymptomatic infants with neonatal polycythemia
Am Heart J
Necrotizing enterocolitis can be caused by polycythemic hyperviscosity in the newborn dog
J Pediatr
The effect of polycythemia and hyperviscosity on bowel ischemia
J Pediatr Surg
Necrotizing enterocolitis in term neonates
Am J Surg
Postnatal changes in serum immunoreactive eryhtropoietin in relation to hypoxia before and after birth
J Pediatr
Prolonged penile erection in the newborn
Urology
Distal gangrene in a polycythemic recipient fetus in twin-twin transfusion
Obstet Gynecol
Effects of neonatal polycythemia and hemodilution on capillary perfusion
J Pediatr
Hemodynamic consequences of polycythemia
J Pediatr
Neonatal hyperviscosity. I. Incidence
Pediatrics
Neonatal polycythemia: I. Early diagnosis and incidence relating to time of sampling
Pediatrics
Neonatal polycythemia: II. Definition related to time of sampling
Pediatrics
Diagnostic value of arterial hematocrits in neonatal polycythemia
Acta Paed Sin
Routine evaluation of blood pressure, hematocrit, and glucose in newborns
Pediatrics
Blood viscosity in the newborn
Arch Dis Child
Neonatal whole blood hyperviscosity: the important factor influencing later neurologic function is the viscosity and not the polycythemia
Clin Hemorheol Microcirc
Neonatal hyperviscosity syndromes
Curr Probl Pediatr
Cord whole blood hyperviscosity: measurement, definition, incidence and clinical features
J Paediatr Child Health
Viscosity in the newborn infant
Acta Paediatr Scand
Evaluation of a screening test for polycythaemia in newborn infants
Aust Paediatr J
Late prognosis in untreated neonatal polycythaemia with minor or no symptoms
Acta Paediatr Scand
Neonatal polycythemia in Hawaii
Hawaii Med J
Prevalence of congenital anomalies and neonatal complications in the offspring of diabetic mothers in Israel
Isr J Med Sci
Neonatal polycythemia in appropriately grown infants of hypertensive mothers
Acta Paediatr
Impact of intrauterine growth retardation and body proportionality on fetal and neonatal outcome
Pediatrics
Does maternal smoking increase the risk of neonatal polycythaemia?
Ir Med J
Maternal smoking and partial exchange transfusion for neonatal polycythemia
Am J Perinatol
Abnormal iron distribution in infants of diabetic mothers: spectrum and marternal antecedents
J Pediatr
Polycythemia of the preterm and full-term newborn infant: relationship between hametocrit and gestational age, total blood solutes, reticulocyte count and blood pH
Biol Neonate
Symptomatic neonatal plethora
Biol Neonate
The effects of early and late cord-clamping on blood viscosity and other hemorrheological parameters in full-term neonates
Acta Paediatr
Relation between hemoglobin discordance and adverse outcome in monochorionic twins
Acta Obstet Gynecol Scand
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