Efficacy of phototherapy in neonatal hyperbilirubinaemia associated with glucose-6-phosphate dehydrogenase deficient status

Hyperbilirubinemia in healthy neonates with glucose-6-phosphate dehydrogenase deficiency

A cohort study was carried out to assess the association between glucose-6-phosphate dehydrogenase (G6PD) deficiency, diagnosed by quantitative enzyme assay, and neonatal hyperbilirubinemia, defined as serum total bilirubin >/=15 mg/dl, in the well-baby nursery of Chang Gung Children's Hospital. Among 42,110 inborn infants, 757 male (3.54%) and 326 female (1.57%) newborns were G6PD-deficient. Compared to the occurrence of hyperbilirubinemia in G6PD-normal newborns (1.41% in male, 1.44% in female) in the well-baby nursery, a significantly higher incidence was observed in both G6PD-deficient male (11.36%) and female (7.06%) newborns. Further analyses demonstrated that the enzyme activity of G6PD in G6PD-deficient male newborns with hyperbilirubinemia (1.56+/-1.37 U/g Hb) were significantly lower than the subjects without hyperbilirubinemia (2.01+/-1.7 U/g Hb). No significant difference was observed in G6PD-deficient female newborns with hyperbilirubinemia (6.91+/-2.76 U/g Hb) compared to those without hyperbilirubinemia (7.81+/-2.84 U/g Hb). These data suggest that the G6PD-deficient neonates are at increased risk for hyperbilirubinemia even in the nursery free from agents that can potentially cause hemolysis to G6PD-deficient red cells. The lower G6PD enzyme activity was associated with the neonatal hyperbilirubinemia in G6PD-deficient male neonates.

Glucose-6-phosphate dehydrogenase deficiency: a potential source of severe neonatal hyperbilirubinaemia and kernicterus

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is a commonly occurring enzyme defect that can lead to severe neonatal hyperbilirubinaemia and kernicterus. Both increased haemolysis, sometimes due to an identifiable chemical trigger or to infection, and diminished bilirubin conjugation, the result of an interaction between G-6-PD deficiency and Gilbert's syndrome, contribute to the pathogenesis of the jaundice. Phototherapy is the mainstay of treatment, with exchange transfusion held in reserve for those neonates who do not respond to phototherapy. Pharmacological agents such as Sn-mesoporphyrins, which prevent bilirubin production by inhibiting the enzyme heme oxygenase, can limit hyperbilirubinaemia and possibly prevent the need for exchange transfusion. Predischarge serum total bilirubin screening is useful in predicting which neonates are at high risk for developing hyperbilirubinaemia. Migration patterns make G-6-PD deficiency a condition which may nowadays be encountered in virtually any corner of the globe and a high degree of physician awareness is essential.

Photooxidant injury to glucose-6-phosphate dehydrogenase-deficient erythrocytes with bilirubin as the sensitizer--an in vitro study

To evaluate the hypothesis that glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes are more prone to photooxidant injury with bilirubin as the sensitizer, we compared the malonyl dialdehyde (MDA) levels and haematocrit values in 11 G6PD-deficient samples with a bilirubin: albumin molar ratio of 1:2 (10 mg% bilirubin, 2.5 g % albumin) photoexposed at 6 microW cm-2 nm-2 (420-460 nm), with 11 of control samples. Twelve hours after photoexposure the incremental changes in MDA levels (OD units) were higher in G6PD-deficient samples [mean (SE) = 0.230 (0.171) vs 0.075 (0.043), p < 0.01]. Antioxidant drugs may have a protective role while G6PD-deficient neonates undergo phototherapy.

Efficacy of phototherapy for hyperbilirubinaemia in infants with the respiratory distress syndrome

OBJECTIVE

To evaluate the efficacy of phototherapy for hyperbilirubinaemia in preterm infants with and without the respiratory distress syndrome (RDS).

METHODOLOGY

Prospective cohort study of preterm infants cared for at Kandang Kerbau Hospital, Singapore: 170 with RDS and 477 without RDS, sepsis or other complications (control group) presenting with non-haemolytic hyperbilirubinaemia at about the same time were exposed to daylight phototherapy when bilirubin concentrations exceeded 255 mumol/L or 222 mumol/L if < 48 h of age. Bilirubin values were monitored 6-hourly during exposure, and daily for at least 2 days post-phototherapy.

RESULTS

The infants were comparable in birthweight, gestational age, postnatal age, haemoglobin, haematocrit and bilirubin values, at start. The response to phototherapy of the infants with RDS was comparable to that of the well preterm infants; the duration of exposure was 50.1 +/- 1.6 (mean +/- s.e.m.) versus 50.1 +/- 1.4 h, 24-hour decline rate 25.71 +/- 1.29% versus 26.32 +/- 0.65, and overall decline rate 0.96 +/- 0.03%/h versus 0.95 +/- 0.02%/h.

CONCLUSION

The presence of RDS did not affect the efficacy of phototherapy for neonatal hyperbilirubinaemia in preterm infants.