Hyperglycemia is a serum glucose concentration > 150 mg/dL (> 8.3 mmol/L).
The most common cause of neonatal hyperglycemia is
Iatrogenic causes usually involve too-rapid IV infusions of dextrose during the first few days of life in very low-birth-weight infants (< 1.5 kg).
The other important cause is physiologic stress caused by surgery, hypoxia, respiratory distress syndrome, or sepsis; fungal sepsis poses a special risk. In premature infants, partially defective processing of proinsulin to insulin and relative insulin resistance may cause hyperglycemia. In addition, transient neonatal diabetes mellitus is a rare self-limited cause that usually occurs in small-for-gestational-age infants; corticosteroid therapy may also result in transient hyperglycemia. Hyperglycemia is less common than hypoglycemia, but it is important because it increases morbidity and mortality of the underlying causes.
Treatment of iatrogenic hyperglycemia is reduction of the IV dextrose concentration (eg, from 10% to 5%) or of the infusion rate; hyperglycemia persisting at low dextrose infusion rates (eg, 4 mg/kg/min) may indicate relative insulin deficiency or insulin resistance.
Treatment of other causes is fast-acting insulin. One approach is to add fast-acting insulin to an IV infusion of 10% dextrose at a uniform rate of 0.01 to 0.1 unit/kg/h, then titrate the rate until the glucose level is normalized. Another approach is to add insulin to a separate IV of 10% D/W given simultaneously with the maintenance IV infusion so that the insulin can be adjusted without changing the total infusion rate. Responses to insulin are unpredictable, and it is extremely important to monitor serum glucose levels and to titrate the insulin infusion rate carefully.
In transient neonatal diabetes mellitus, glucose levels and hydration should be carefully maintained until hyperglycemia resolves spontaneously, usually within a few weeks.
Any fluid or electrolytes lost through osmotic diuresis should be replaced.