Approach to the diagnosis of neonates and infants with persistent hypoglycemia

Abstract

The diagnostic evaluation of neonates and infants with persistent hypoglycemia requires a systematic approach to evaluate the integrity of the fuel and hormone responses during the development of fasting hypoglycemia. This is best accomplished by performing a closely monitored fasting test. The diagnosis of hyperinsulinism relies heavily on demonstrating inappropriate effects of insulin on fasting adaptation, i.e., inappropriate suppression of lipolysis and ketogenesis and inappropriate preservation of liver glycogen reserves as hypoglycemia develops. Once the diagnosis of hyperinsulinism has been established, evidence from the timing and the pattern of the hypoglycemia, the presence or absence of hyperammonemia, the response to substrate challenge tests (i.e., glucose and protein), and the results of genetic testing can specify the type of hyperinsulinism. This knowledge will allow one to implement the correct therapy and determine if the patient is a candidate for curative surgical approach such as is possible in focal KATP-HI and insulinomas.