Neonatal hypoglycemia: lack of evidence for a safe management

Neonatal hypoglycemia affects up to 15% of all newborns. Despite the high prevalence there is no uniform definition of neonatal hypoglycemia, and existing guidelines differ significantly in terms of when and whom to screen for hypoglycemia, and where to set interventional thresholds and treatment goals. In this review, we discuss the difficulties to define hypoglycemia in neonates. Existing knowledge on different strategies to approach this problem will be reviewed with a focus on long-term neurodevelopmental outcome studies and results of interventional trials. Furthermore, we compare existing guidelines on the screening and management of neonatal hypoglycemia. We summarize that evidence-based knowledge about whom to screen, how to screen, and how to manage neonatal hypoglycemia is limited - particularly regarding operational thresholds (single values at which to intervene) and treatment goals (what blood glucose to aim for) to reliably prevent neurodevelopmental sequelae. These research gaps need to be addressed in future studies, systematically comparing different management strategies to progressively optimize the balance between prevention of neurodevelopmental sequelae and the burden of diagnostic or therapeutic procedures. Unfortunately, such studies are exceptionally challenging because they require large numbers of participants to be followed for years, as mild but relevant neurological consequences may not become apparent until mid-childhood or even later. Until there is clear, reproducible evidence on what blood glucose levels may be tolerated without negative impact, the operational threshold needs to include some safety margin to prevent potential long-term neurocognitive impairment from outweighing the short-term burden of hypoglycemia prevention during neonatal period.

Disability Prediction by Early Hammersmith Neonatal Neurological Examination: A Diagnostic Study

BACKGROUND AND OBJECTIVES

Hammersmith Neonatal Neurologic Examination (HNNE) is used to identify term and preterm infants at risk of neurodevelopmental disability. The test is recommended at corrected term age in preterm; and around 2 weeks postnatal age in term neonates. As the current trend is to discharge based on physiological stability, it may not be feasible to perform HNNE at recommended age. The authors investigated whether predictive ability of the test for neurodevelopmental disability remained unchanged if performed early (before discharge).

METHODS

The authors enrolled preterm and at-risk term neonates. HNNE PE was performed before discharge in all infants. The test was repeated in preterm infants at 40 weeks postmenstrual age and in term neonates at 2 weeks of age (HNNE RA). Neurodevelopmental disability was assessed at 1 year of age.

RESULTS

HNNE PE was done in 125 neonates (103 preterm, 22 term neonates). HNNE RA was done in 58% infants. Neurodevelopmental disability was assessed in 84 (67%) of infants. Neurodevelopmental disability was noted in 14/84 (16.6%) babies. The receiver operating characteristic curve of raw scores showed that area under the curve for HNNE PE (0.71) and HNNE RA (0.66) were similar. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for both the tests were similar for a cutoff optimality score of 32.5. HNNE PE could be performed up to 4 weeks earlier than HNNE RA with the same predictive ability for neurodevelopmental disability.

CONCLUSIONS

HNNE PE was as reliable as HNNE RA in predicting neurodevelopmental disability at 1 year of age. Completion of the test is assured and provides several weeks lead time for early intervention.