Iowa Neonatology Handbook: General

Hypocalcemia

John A. Widness, MD
Peer Review Status: Internally Peer Reviewed

1. Definition: plasma ionized calcium concentration < 3 mg/dL (0.75 mmol/L).
2. Infants at risk:
   1. premature infants
   2. infants of diabetic mother
   3. infants with birth asphyxia infants with certain congenital, genetic and hormonal disorders
3. Categorization by age of onset:
   1. Early: In pre-term infants who has received sodium bicarbonate for the treatment of metabolic acidosis, the risk is greatest at 12 to 24 hours of life. Most hypocalcemic neonates without symptoms will normalize their serum calcium levels by 72 hours of age with or without treatment.
   2. Late: after 7 days infants receiving formulas with low calcium and high phosphorus contents (rare today).
   3. Very late osteopenia of prematurity: see section on neonatal nutrition.
4. Symptoms: extreme jitteriness, seizures (including apnea), bleeding and/or decreased myocardial contractility.
5. Treatment: Treatment of infants whose symptoms are thought to be due to hypocalcemia should be begun as soon as possible. Treatment of asymptomatic infants is controversial since in the vast majority of infants the condition is currently thought to have no short or long terms effects. Nevertheless, some authorities recommend treatment of low calcium levels.
   1. Once a decision to treat has been made, initial treatment should be 100 to 200 mg/kg of 10% calcium gluconate by slow i.v. "push", i.e., over at least 30 minutes, followed by a continuous i.v. infusion of 400 mg/kg/day calcium gluconate. Alternatively, calcium may be administered as a slow infusion (over 30 to 60 minutes), given at a dose of 100 mg/kg every 6 hours. If other calcium salts are used, e.g. calcium chloride, the dose will be different. Calcium gluconate should be infused through a peripheral venous line and not given with sodium bicarbonate, dioxin, or antibiotics. If there is a question as to compatibility of calcium with other drugs, contact the Hospital Pharmacy (6-1849).
   2. In treated infants plasma ionized calcium level should be monitored every 12 to 24 hours. Once the calcium level has normalized, and parenteral and/or enteral sources of calcium intake have been begun, the infusion of calcium should be decreased by 50% after 24 hours, and then discontinued after an additional 24 hours if follow-up plasma calcium levels remain normal and the patient is asymptomatic.
   3. To prevent the very late osteopenia occurring most commonly in sickest and least mature premature infants, optimal enteral and parenteral calcium nutritional support on a long term basis are needed (see sections on neonatal nutrition and feeding).

Reference:

Salle BL, Delvin E, Glorieux F, David L. Human neonatal hypocalcemia. Biol Neonate 1990;58:1:22-31.

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