Hypoglycemia
A blood glucose level of less than 40 mg/dL may produce seizures. Hypoglycemia is likely to occur in neonates with low birth weight, hypoxic-ischemic encephalopathy, or diabetic mothers. Neonates with Beckwith-Weidemann syndrome (macrosomia, omphalocele, macroglossia, and visceromegaly), insulin producing tumors (nesidioblastosis), pituitary hypoplasia (Figure 40.1), inborn errors of metabolism (fructose intolerance, fructose-1,6 diphosphatase deficiency, maple syrup urine disease, propionic and methylmalonic acidemia), and neonates large or small for gestational age may develop hypoglycemia. Maternal use of tocolytic agents, chlorpropamide, or propranolol during pregnancy may predispose the neonate to hypoglycemia.

A	B	C

Figure 40.1— Pituitary agenesis. [A] Micropenis. [B and C] Absence of the pituitary gland.

Most neonates with hypoglycemic seizures are tachypneic, hypotonic, and lethargic between seizures, but some look healthy between seizures. Preferential bilateral occipital lobes infarcts (Figure 40.2) may occur in neonates with hypoglycemia often leading to blindness.

A	B	C

Figure 40.2— Bilateral occipital lobe infarcts. [A] CT done at 5 days of age. [B] MRI done at 16 days of age. [C] MRI done at 38 days of age.

The treatment of hypoglycemic seizures is glucose 200 mg/kg as 10% solution intravenously over 1 minute (2 mL/kg over 1 minute) followed by a constant infusion of 10% glucose at 8 mg of glucose per kg per minute. Glucose levels should be monitored frequently and the glucose infusion adjusted accordingly. Glucagon 300 micrograms/kg may be given intramuscularly in large infants if an intravenous line can not be placed immediately.

Hypocalcemia
Seizures may occur with a total serum calcium level of less than 7 mg/dL or an ionized calcium level of less than 1.2 mg/dL. Hypocalcemia in the first week of life usually occurs in low birth weight neonates, infants of mothers with diabetes mellitus or hypoparathyroidism, or neonates with hypoxic-ischemic encephalopathy.