Addressing Hypoglycemia and Hyperglycemia

Abstract

1. William W. Hay Jr, MD* 1. 2. *Coeditor Ordinarily, invited authors will write the review articles and commentaries for NeoReviews . However, as the coeditor primarily responsible for this inaugural edition, I wanted to take the prerogative to write an introduction that will set the stage for what each edition will include and explain how David Stevenson and I have developed topics, authors, content, and format. We chose the topics of hypoglycemia and hyperglycemia for this first edition for several reasons that should illustrate our vision of NeoReviews . Neonatal hypoglycemia is both a historical and a current “hot topic.” It has been studied thoroughly and has been the subject of extensive debate, yet it remains a common problem that is difficult to define, understand, and manage. The evidence is very clear from human and animal studies that severe, prolonged hypoglycemia leads to acute neurologic injury that often can have permanent sequelae. Frequently overlooked because of this ultimate serious outcome is the more common problem of hypoglycemia leading to cellular energy failure and generalized organ dysfunction. ### DEFINITION Despite such serious and common consequences and years of investigation into its characteristics, the definition of hypoglycemia remains elusive. Fifty years ago, Norval, Kennedy, and Berkson defined the normal concentration range of blood sugar (glucose) in term newborns as 0.83 to 6.66 mmol/L (15 to 120 mg/dL), with a mean of 3.39±0.77 mmol/L (SD) (61.0±13.8 mg/dL). Ninety-five percent of infants had a concentration of 2.89 to 3.89 mmol/L (52 to 70 mg/dL). Such values are perfectly acceptable and within the normal range today. Why, therefore, is there still controversy over what is considered the normal lower limit of glucose concentration in blood or plasma of newborns and what values constitute hypoglycemia? As discussed by Jane E. McGowan, MD, in this issue, many infants experience transiently low and highly variable glucose concentrations, but …