Topics Discussed: hematology; polycythemia; polycythemia neonatorum.
Excerpt:"Problem. The hematocrit (Hct) is 68% in a newborn. The upper limit of a normal Hct for a newborn peripheral venous sample is 65%. Polycythemia occurs in 0.4–12% of newborn infants and is rare in premature infants <34 weeks' gestation.
Immediate questions
- What is the central hematocrit (Hct)? In blood obtained by heelstick, the Hct may be falsely elevated by 5–15%. Treatment should never be initiated based on heelstick Hct values alone; a central (peripheral venous phlebotomy) Hct is needed. If the sample is from the umbilical vein or radial artery, the upper limit of normal is 63%.
- Does the infant have symptoms of polycythemia? Many infants with polycythemia are asymptomatic. One study found that feeding problems and lethargy were the most common symptoms. There are many symptoms and signs of polycythemia, which can include the following:
- Central nervous system. Lethargy, hypotonia, irritability, jitteriness, weak sucking reflex, vomiting, seizures, tremulousness, apnea, sleepiness, exaggerated startle, cerebrovascular accidents.
- Cardiovascular. Heart murmurs, congestive heart failure, cyanosis, plethora, tachycardia, cardiomegaly.
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