Hypoglycemia in newborns

Hypoglycemia is a serum glucose level of less than 40 mg / dL (less than 2.2 mmol / L) in term infants or less than 30 mg / dl (<1.7 mmol / L) in preterm infants. Risk factors include prematurity and intrapartum asphyxia. The most common causes are insufficient glycogen stores and hyperinsulinemia. Symptoms of hypoglycemia include tachycardia, cyanosis, convulsions and apnea.

The diagnosis of "hypoglycemia" is assumed empirically and is confirmed by determining the level of glucose. The prognosis depends on the cause, the treatment is enteral nutrition or the intrusive injection of glucose.

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What causes hypoglycemia in newborns?

Hypoglycemia in newborns can be transient or permanent. The reasons for transient hypoglycemia are an insufficient amount of substrate or immaturity of enzyme function, which leads to insufficient glycogen stores. The causes of persistent hypoglycemia are hyperinsulinism, violation of counterinsulant hormones and hereditary metabolic diseases [eg, glycogenosis, gluconeogenesis disorder, fatty acid oxidation disorder].

Insufficient glycogen reserves at birth are often found in preterm infants with very low birth weight, children small to gestation due to placental insufficiency, and children experiencing intrapartum asphyxia. Anaerobic glycolysis depletes glycogen stores in these children, and hypoglycemia can develop at any time in the first few days, especially if the feedings are maintained at a long interval or the nutrient intake is low. Therefore, maintaining the intake of exogenous glucose is important for preventing hypoglycemia.

Transient hyperinsulinism is most common in children from mothers with diabetes mellitus. It also often occurs with physiological stress in children, small to gestation. Less common causes include hyperinsulinism (transmitted both by autosomondominant and by autosomnocessive inheritance type), severe fetal erythroblastosis, Beckwith-Wiedemann syndrome (in which islet cell hyperplasia is combined with signs of macroglossia and umbilical hernia). Hyperinsulinemia is characterized by a rapid drop in serum glucose levels in the first 1-2 hours after birth, when the constant flow of glucose through the placenta ceases.

Hypoglycemia can also develop if intravenous glucose solution is abruptly discontinued.

Symptoms of hypoglycemia in newborns

Many children have no hypoglycemia. Long or severe hypoglycemia causes both vegetative and neurological signs of central genesis. Vegetative symptoms include sweating, tachycardia, weakness and chills or tremors. Central neurological signs of hypoglycemia include convulsions, coma, episodes of cyanosis, apnea, bradycardia or respiratory distress, hypothermia. There may be lethargy, poor appetite, hypotension and tachypnea. All manifestations are nonspecific and are also noted in newborns experiencing asphyxia, with sepsis or hypocalcemia or with opioid withdrawal syndrome. Therefore, patients at risk with or without these symptoms require immediate monitoring of capillary blood glucose. An abnormally low level is confirmed by the determination of glucose in the venous blood.

Treatment of hypoglycemia in newborns

Most newborns in the high-risk group are treated proactively. For example, children from women with insulin-dependent diabetes often begin after intravenous infusion with 10% glucose solution or give glucose orally, as well as patients with prematurely premature infants, or children with respiratory distress syndrome. Newborns at risk should receive early, frequent feeding with a mixture to provide them with carbohydrates.

Any newborn who has a glucose level less than or equal to 50 mg / dl should begin appropriate treatment with enteral feeding or intravenous glucose solution with a concentration of up to 12.5%, at a rate of 2 ml / kg for more than 10 minutes; higher concentrations can be administered, if necessary, via a central catheter. The infusion should then continue at a rate providing 4-8 mg / (kg min) of glucose [i.e. Ie 10% glucose solution at a rate of approximately 2.5-5 ml / (kg h)]. Serum glucose should be monitored in order to regulate the infusion rate. With the improvement of the condition of the newborn, enteral feeding can gradually replace intravenous infusion, while glucose concentration continues to be controlled. Intravenous glucose infusion should always decrease gradually, as sudden withdrawal can cause hypoglycemia.

If a newborn with hypoglycemia is difficult to start with an intravenous infusion, glucagon at a dose of 100-300 μg / kg intramuscularly (max. 1 mg) usually rapidly increases the glucose level, this effect lasts 2-3 hours, except for newborns with depleted glycogen stores. Hypoglycemia refractory to glucose infusion at high speed can be treated with hydrocortisone at a dose of 2.5 mg / kg intramuscularly 2 times a day. If hypoglycemia is refractory to treatment, other causes (eg, sepsis) should be excluded and, possibly, an endocrinological examination should be prescribed to detect persistent hyperinsulinism and gluconeogenesis or glycogenolysis disorders.