Unexplained extreme hyperbilirubinemia among neonates in a multihospital healthcare system.

We report a series of neonates who developed a total serum bilirubin (TSB) >20mg/dL during a recent ten-year period in a multihospital healthcare system. The incidence of a TSB >20mg/dL fell after instituting a pre-hospital discharge bilirubin screening program in 2003/2004 (91.3 cases/10,000 births before vs. 72.4/10,000 after), but the incidence has subsequently remained unchanged. No specific cause for the hyperbilirubinemia was identified in 66% of (n=32) cases with a TSB >30 mg/dL or in 76% of (n=112) cases with a TSB 25.0-29.9 mg/dL. We hypothesized that hemolysis was a common contributing mechanism, but our review of hospital records indicated that in most instances these infants were not evaluated sufficiently to test this hypothesis. Records review showed maternal and neonatal blood types and direct antiglobulin testing were performed in >95% cases, but rarely were other tests for hemolysis obtained. In the ten-year period reviewed there were zero instances where erythrocyte morphology from a blood film examination or Heinz body evaluation by a pediatric hematologist or pathologist were performed. In 3% of cases pyruvate kinase was tested, 3% were evaluated by hemoglobin electrophoresis, 3% had a haptoglobin measurement, and 16% were tested for G6PD deficiency. Thus, determining the cause for hyperbilirubinemia in neonates remains a problem at Intermountain Healthcare and, we submit, elsewhere. As a result, the majority of infants with a TSB >25mg/dL have no specific causation identified. We speculate that most of these cases involve hemolysis and that the etiology could be identified if searched for more systematically. With this in mind, we propose a "consistent approach" to evaluating the cause(s) of hyperbilirubinemia among neonates with a TSB >25mg/dL.