A newborn boy is evaluated on arrival in the nursery. He was born 3 hours ago by spontaneous vaginal delivery at 40 weeks gestation after an uncomplicated pregnancy. Apgar scores were 9 at 1 minute and 10 at 5 minutes after birth. His mother has no significant medical history and does not take any medications. Temperature is 36.7 C (98 F), pulse is 124/min, and respirations are 26/min. He is awake, alert, and active with a strong cry. His head is normocephalic and atraumatic with an open flat anterior fontanelle. Pupils are equal and reactive to light and accommodation, and red reflexes are present bilaterally. The nares are patent, there is no cleft lip or palate, and the pharynx is not erythematous. Clavicles are intact without crepitus. S1 and S2 are normal without murmurs, and lungs are clear to auscultation bilaterally. The abdomen is soft, nontender, and nondistended with normal bowel sounds and no organomegaly. Femoral pulses are normal and symmetrical. All extremities move spontaneously and there is no edema. There are no rashes, skin lesions, or jaundice, but the complexion appears ruddy with generalized erythema. Blood samples obtained from the heel through simple prick method reveal a hematocrit of 70%.
What is the most appropriate next step in management of this patient?

Question

A newborn boy is evaluated on arrival in the nursery.  He was born 3 hours ago by spontaneous vaginal delivery at 40 weeks gestation after an uncomplicated pregnancy.  Apgar scores were 9 at 1 minute and 10 at 5 minutes after birth.  His mother has no significant medical history and does not take any medications.  Temperature is 36.7 C (98 F), pulse is 124/min, and respirations are 26/min.  He is awake, alert, and active with a strong cry.  His head is normocephalic and atraumatic with an open flat anterior fontanelle.  Pupils are equal and reactive to light and accommodation, and red reflexes are present bilaterally.  The nares are patent, there is no cleft lip or palate, and the pharynx is not erythematous.  Clavicles are intact without crepitus.  S1 and S2 are normal without murmurs, and lungs are clear to auscultation bilaterally.  The abdomen is soft, nontender, and nondistended with normal bowel sounds and no organomegaly.  Femoral pulses are normal and symmetrical.  All extremities move spontaneously and there is no edema.  There are no rashes, skin lesions, or jaundice, but the complexion appears ruddy with generalized erythema.  Blood samples obtained from the heel through simple prick method reveal a hematocrit of 70%. 
What is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf7a_8228_8f63_03773155b374_MD0005_00 Neonatal polycythemia, which affects up to 5% of newborns, is defined as a hematocrit >65% or hemoglobin >22 g/dL. It is most often observed at 2-3 hours of life as a result of increased hemoglobin production, possibly due to unstable newborn vasomotor factors or in response to relative uterine hypoxia. Factors that contribute to the development of polycythemia include delayed clamping of the umbilical cord, gestational diabetes, maternal hypertension, and intrauterine growth restriction. In most cases, newborns are asymptomatic and the hematocrit value declines to baseline levels within the first 24 hours of life. However, polycythemia can be associated with complications (eg, hypoglycemia, hyperbilirubinemia, hyperviscosity, hypoperfusion, tissue hypoxia), due mostly to increased red blood cell volume. There may be significant variability in measurements with capillary samples (eg, heel prick). Therefore, if the hematocrit is >65% on a heel prick, it should be confirmed by rechecking a sample from peripheral venous blood, which is more reliable, unaffected by changes in temperature and blood flow, and often up to 15% lower than a hematocrit taken from a capillary sample (Choice D). (Choice A) Checking blood type and Coombs test is an important part of the workup for a newborn with suspected ABO incompatibility. However, ABO incompatibility leads to hemolytic anemia rather than polycythemia. (Choices B and C) Checking serum blood urea nitrogen and creatinine levels helps to determine hydration status, as dehydration can be both a source and an outcome of polycythemia. Hypothyroidism or hyperthyroidism can also cause polycythemia. However, it is more important to determine whether polycythemia is actually present before conducting further workup. Educational objective: Neonatal polycythemia is diagnosed when the peripheral venous hematocrit is >65%. High hematocrit levels that are obtained from capillary samples (usually from a heel prick) are unreliable and must be confirmed through venous blood sampling. References: Management of polycythemia in neonates. (http://www.ncbi.nlm.nih.gov/pubmed/20725868)

A Newborn Boy Is Evaluated on Arrival in the Nursery