In a newborn, glucose levels rapidly fall to a low point in the 1st 2 hours of life which is usually transient (as the source of maternal glucose is removed) and the infant achieves homeostasis. This transition is usually smooth but there are certain high risk infants who are at risk of hypoglycemia.

High risk infants :

Infants with increased utilization of glucose (Hyperinsulinism):

• Infants of Diabetic mothers.
• Erythroblastosis fetalis.
• Beckwith Wiedman syndrome.
• Nesidioblastosis or islet cell adenoma.

Infants with decreased glucose stores / production :

• Premature infants
• Intra-uterine growth retardation (IUGR)
• Inadequate caloric intake

Increased utilization of glucose / stressed infants :

• Sepsis
• Asphyxia
• Respiratory distress
• Hypothermia
• Polycythemia
• Shock

Inborn errors of metabolism in infants :

• Glycogen storage disorders
• Galactosemia
• Organic acidemias

Endocrinal deficiencies in infants :

• Adrenal insufficiency
• Congenital hypopituitarism

Diagnosis :

Most infants with transient hypoglycemia have no symptoms. The symptoms, when present are non-specific and include jitteriness, lethargy, cyanosis, ,apnea, seizures, and poor feeding. Hence, a blood sugar of less than 35mg% in any infants is considered as significant hypoglycemia. However, for all practical purposes, the therapy is initiated if the level falls below 40mg%. Hence, all infants at risk for hypoglycemia should be screened with reagent strips with the first 2 hours of life. The interval between subsequent measurements of glucose levels depends on clinical judgement. If reagent strips show low glucose levels then blood sugar levels should be determined by collecting blood in a fluoride bulb.

Treatment :

All high risk infants should be monitored by reagent strips. If diagnosed as having hypoglycemia, most infants require 2-4 ml/kg of 10% Dextrose IV in one minute followed by 100 ml /kg/day of 10% Dextrose which is equivalent to 7-8 mg/kg/min glucose. This is equivalent to a normal full term baby's requirement. Some infants may require around 10-15 mg/kg/min of glucose which can be given by either increasing the D10W infusion rate or changing to D12.5W or D15W.D12.5W and above should be given by a central line as it may cause extravasation & tissue necrosis if give by a peripheral line.

Large boluses of glucose should be avoided as the infants may release more insulin causing rebound hypoglycemia.

Once hypoglycemia has been diagnosed, IV glucose should be given until feeds are started and then IV infusion is tapered off.

For infants who are unable to maintain glucose levels, at even 12 mg/kg /min of glucose infusion, consider hydrocortisone (10mg/kg /day IV in divided doses). Before giving hydrocortisone, collect blood for insulin and cortisol level measurements. For patients with adequate glycogen stores, glucagon (0.1mg/kg) IM can temporarily increase the glucose level for 2-3 hours in case of an emergency.

For asymptomatic infants, who are at risk of hypoglycemia, feeds should be started early and should consist of frequent small feeds.

Complications of hypoglycemia :

Prolonged hypoglycemia is associated with neurological damage. IV glucose can cause hypoglycemia leading to hyperosmolarity, osmotic diuresis and dehydration.

Further workup :

When hypoglycemia lasts over 1 week, evaluate some of the rare cause of hypoglycemia. The following measurements should be considered.

• Blood Insulin
• Serum Growth hormone
• Serum Cortisol
• Serum ACTH
• Serum Thyroxine
• Serum Glucagon
• Urinary & plasma amino acids
• Urine reducing substances & ketones