Case Report: An unexpected diagnosis in a newborn with severe prolonged hyperbilirubinemia without hemolysis
An unexpected diagnosis in a newborn with severe prolonged hyperbilirubinemia without hemolysis
This case describes a full term baby boy of a healthy mother born after a normal pregnancy, who developed jaundice on the second day after birth, with a total serum bilirubin (TSB) of 25.0 mg/dL (427 μmol/L) on the ninth day. Initial blood tests excluded common causes of neonatal hyperbilirubinemia, e.g. iso-immunization disorders, hemolysis and hypothyroidism. As bilirubin levels continued to remain high despite phototherapy, further investigation was warranted, revealing a decreased glucose 6 phosphate dehydrogenase (G6PD) activity in the red blood cells of the newborn. After eleven days of phototherapy the patient was discharged with a TSB of 21.5 mg/dL (368 μmol/L).
Background
Neonatal jaundice is commonly observed among newborn infants, caused by hyperbilirubinemia. Severe hyperbilirubinemia should be recognized and treated to prevent kernicterus, a condition characterized by irreversible neurological damage. In most cases, hyperbilirubinemia results from a physiological increase in the unconjugated bilirubin concentration, combined with immature mechanisms for conjugation and enhanced enterohepatic circulation. However, certain conditions (e.g. prolonged jaundice, onset in the first 24 hours after birth, rapid rise in serum bilirubin, etc.) should raise the suspicion of an underlying pathologic mechanism. In general, unconjugated hyperbilirubinemia can be caused by (1) an increased, pathologic production of bilirubin, (2) a deficiency of hepatic uptake, (3) an impaired conjugation of bilirubin, (4) an increased enterohepatic circulation of bilirubin, or (5) a combination of the above [1]. In case of pathologic unconjugated hyperbilirubinemia, an increased production of bilirubin due to hemolysis is the most likely cause. Therefore, a common approach in the diagnostic work-up of neonatal unconjugated hyperbilirubinemia is to differentiate between hemolytic and non-hemolytic diseases as a first step [2].