Prognostic Significance of Early Elevated Serum Uric Acid Concentrations in Low Birthweight Infants 1149

Abstract

Uric acid (UA) concentrations can be elevated after ischemia-reperfusion injury and high levels in the first day of life have been associated with intracranial pathology in low birthweight infants (Pediatr Res 1996; 39: 238A). To determine the prognostic significance of high serum UA concentrations in the first 24 hours after birth, the records of 154 inborn infants who weighed 7.5 mg/dl and by univariate analysis was significantly related to gestational age, peak serum creatinine, serum HCO3 and base deficit, the presence of pregnancy-induced hypertension (PIH), intrauterine growth retardation and how long after birth the sample was obtained. By multiple logistic regression, peak creatinine concentrations, base deficit and time of sample were risk factors for high serum UA concentrations. There were no significant differences in UA concentrations between those with any IVH or PVL(n = 41, UA=5.35 ± 0.32 mg/dl) and those with none (n=97, UA=5.88± 0.22 mg/dl, p > 0.05), nor did UA concentrations differ between the survivors vs the 21 who died (5.73 ± 0.19 vs 5.45 ± 0.43 mg/dl, p > 0.05). Elevated UA concentrations were not found in those with more severe intracranial pathology (Grades III and IV IVH and/or PVL) nor in the group defined as bad outcome (died or had IVH/PVL). Of the 132 infants eligible for follow-up, 79 (60%) were seen at a median age of 11 months(range 5-29 mo). The 20 infants with neurodevelopmental or neuromotor abnormalities had a first day UA concentration of 5.38 ± 0.38 compared with 6.03± 0.33 for those with a normal exam (p > 0.05). Elevated serum UA concentrations in the first 24 hr of life do not relate to intracranial pathology, death or abnormal neurological outcome. Since the concentrations are higher in the presence of maternal hypertension, serum creatinine and how long after birth the sample is obtained, it is possible that any detection of elevated serum UA from ischemia-reperfusion injury in the infant is obscured by transplacental passage of UA from the mother (serum UA is higher in mothers with PIH) and from a longer half-life for UA in the infant's circulation during the first day of life.