Hypocalcaemia in children

E83.5

DESCRIPTION

The main causes of hypocalcaemia in children are:

  • vitamin D deficiency,
  • calcium deficiency,
  • magnesium deficiency,
  • reduced parathyroid hormone production or resistance,
  • impaired renal function.

DIAGNOSTIC CRITERIA

Clinical

  • Signs and symptoms of tetany include:
    • paraesthesia,
    • positive Chvostek’s sign,
    • cramps,
    • positive Trousseau’s sign,
    • carpopedal spasm,
    • weakness,
    • laryngospasm,
    • lethargy,
    • prolonged QT interval on the ECG.

Investigations

  • Blood level to establish cause:
    • calcium,
    • albumin,
    • phosphate,
    • magnesium,
    • ALP
    • 25 Hydroxyvitamin D.

MEDICINE TREATMENT

Acute hypocalcaemia

  • Calcium gluconate 10%, IV, 1–2 mL/kg administered over 5–10 minutes, 6–8 hourly.
    • Maximum dose: 10 mL.
    • ECG monitoring is advised.

If hypomagnesaemic:

  • Magnesium sulphate 50%, IV/IM, 0.2 mL/kg every 12–24 hours.

Chronic therapy

Long-term therapy depends on the cause.
Manage hypophosphataemia or hyperphosphatemia, depending on the cause of hypocalcaemia, before long-term calcium is initiated.

  • Calcium, elemental, oral, 50 mg/kg/day until normal calcium level is achieved (given with meals).
    • Maintenance dose: 30 mg/kg/day.

If vitamin D deficient:

  • Vitamin D, oral:
Under 6 months 2500 IU/day
6 months -12 years 5 000 IU/day
12 - 18 years 10 000 IU/day

For hypoparathyroidism and pseudohypoparathyroidism:

  • Calcitriol, oral, 0.01–0.04 mcg/kg/day.
    OR
  • Alfacalcidol, oral, 0.05 mcg/kg/day.
    • If < 20 kg: 0.05 mcg/kg/day.
    • If > 20kg: 1 mcg/day.

REFERRAL

  • Chronic hypocalcaemia.