Hypocalcaemia, neonatal

P71.1

DESCRIPTION

Acute symptomatic hypocalcaemia may present within the first 72 hours of birth (early hypocalcaemia) or after 72 hours of birth (late hypocalcaemia) with apnoea, irritability, seizures, jitteriness or prolonged QTc interval on ECG.

Causes of early hypocalcaemia include:

  • Prematurity.
  • Respiratory distress syndrome.
  • Asphyxia/hypoxia.
  • Neonate of diabetic mother.
  • Sepsis.

Causes of late hypocalcaemia include:

  • Maternal hyperparathyroidism.
  • Congenital hypoparathyroidism.
  • Renal failure.
  • Hypomagnesaemia.
  • High phosphate feeds.
  • Vitamin D deficiency.

DIAGNOSTIC CRITERIA

  • Total serum calcium < 1.8 mmol/L, or
  • Ionised calcium < 0.7 mmol/L.

MEDICINE TREATMENT

Symptomatic hypocalcaemia:

  • Calcium gluconate 10%, IV, 100–200 mg/kg/dose 6–8 hourly.

1 mL of calcium gluconate 10% = 100 mg calcium gluconate

= 10 mg elemental calcium

= 0.23 mmol calcium

Do not administer ceftriaxone, within 48 hours of administering calcium.

Correct hypomagnesaemia before administering 10% calcium gluconate.

  • Magnesium sulphate 50%, IV, 0.25 mL/kg.
    • Monitor levels until deficits are reduced.

Exchange transfusion

  • Calcium gluconate 10%, IV infusion, administered over 10 minutes.
    • 100mg for every 100 mL citrated blood exchanged.

Acute hypocalcaemia with seizures

  • Calcium gluconate 10%, IV infusion, 100–200 mg/kg, administered over 10 minutes. Repeat in 15 minutes if necessary.
    • Dilute 1:1 with dextrose 5% or sodium chloride 0.9%.
    • Do not use calcium chloride.

Note: Rapid infusion causes bradycardia/dysrhythmias. Electrocardiographic monitoring is advised. Monitor the heart rate.

CAUTION
Do not mix calcium gluconate with bicarbonate or fluids containing phosphate as precipitation may occur. Extravasation of calcium can cause tissue necrosis.
Do not give intra-arterially or via umbilical venous catheters placed near the heart or inside the liver.

REFERRAL

  • Persisting or recurrent unexplained hypocalcaemia.