Neonatal bilirubin production-conjugation imbalance: effect of glucose-6-phosphate dehydrogenase deficiency and borderline prematurity.

Abstract

OBJECTIVE:

To evaluate relations between production and conjugation of bilirubin in the pathophysiology of jaundice in glucose-6-phosophate dehydrogenase (G6PD) deficient neonates.

METHODS:

Term and borderline premature (35-37 weeks gestational age), healthy, male, G6PD deficient neonates were studied close to the beginning of the 3rd day. Blood carboxyhaemogobin corrected for inspired CO (COHbc; an index of bilirubin production) and serum total conjugated bilirubin (TCB; a reflection of bilirubin conjugation) were measured in simultaneously drawn blood samples by gas chromatography and reverse phase high performance liquid chromatography respectively. A bilirubin production-conjugation index comprising COHbc/TCB was determined; a high index reflects imbalance between the bilirubin production and conjugation processes. COHbc and TCB individually and the production-conjugation index were studied in relation to serum total bilirubin (STB) concentration.

RESULTS:

Fifty one G6PD deficient neonates were sampled at 51 (8) hours. COHbc values did not correlate with STB (r=0.22, p=0.15). TCB did correlate inversely with STB (r=-0.42, p=0.004), and there was a positive correlation between the production-conjugation index and STB (r=0.45, p=0.002). The production-conjugation index (median (interquartile range)) was higher in the premature (n=8) than term neonates (2.31 (2.12-3.08) v 1.05 (0.53-1.81), p=0.003). This difference was the result of changes in TCB.

CONCLUSIONS:

The data show that jaundice in G6PD deficient neonates is the result of an imbalance between production and conjugation of bilirubin with a tendency for inefficient bilirubin conjugation over increased haemolysis in its pathogenesis. Borderline premature infants are at special risk of bilirubin production-conjugation imbalance.

• Authors: M Kaplan, M Muraca, H J Vreman, C Hammerman, M T Vilei, F F Rubaltelli, D K Stevenson
• Journal: Archives of disease in childhood. Fetal and neonatal edition (Arch Dis Child Fetal Neonatal Ed) Vol. 90 Issue 2 Pg. F123-7 (Mar 2005) ISSN: 1359-2998 [Print] England
• PMID: 15724035 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Carboxyhemoglobin
• Bilirubin

Topics

• Bilirubin (biosynthesis, blood, metabolism)
• Carboxyhemoglobin (analysis)
• Glucosephosphate Dehydrogenase Deficiency (complications, metabolism)
• Humans
• Infant, Newborn
• Infant, Premature
• Infant, Premature, Diseases (etiology, metabolism)
• Jaundice, Neonatal (etiology, metabolism)
• Male
• Regression Analysis