On this page


AKA: hypocalcaemia

Evaluation and management of low blood calcium in pediatric patients



  • Hypoparathyroidism
    • DiGeorge syndrome
  • Hypomagnesemia (impairs secretion, action of PTH)
  • Renal PO₄³⁻ wasting with hypercalciuria (hereditary hypophosphatemic rickets with hypercalciuria)
  • Autoimmune polyendocrinopathy, candidiasis, ectodermal dystrophy (APECED) syndrome
    • Destroys multiple endocrine glands, including parathyroid

High PTH

  • Vitamin D deficiency/resistance
  • Nutritional
    • Kidney disease
    • Liver disease
  • Pseudohypoparathyroidism
  • Hungry bone syndrome
  • Inadequate intake

Neonatal hypocalcemia

  • Prematurity
  • Intrauterine growth restriction
  • Infant of diabetic mother


  • Hypoalbuminemia
    • Calcium is highly albumin bound, but only the unbound calcium is physiologically active.
      • If hypoalbuminemia is also present, there may be proportionally more unbound (ionized) calcium; therefore, the ionized calcium should be measured
      • Some will “correct” the calcium for the albumin level (for each 1 g/dL below normal albumin level, add 0.8 mg/dL to the serum calcium), but evidence does not support this practice [PMID 34197298]
  • Ionized calcium (iCa) is more reliable
    • Not confounded by albumin level
  • Calcium is bound by citrate
    • Citrate-bound calcium is included in total serum calcium level but will result in a lower iCa level
    • If iCa low, ensure not being drawn from line with blood products running in the line (e.g., in secondary lumen)
  • Lab error, specimen handling issues

Signs and symptoms

  • Characteristically presents with neuromuscular irritability, but can be highly variable
  • Weakness
  • Paresthesias
  • Perioral numbness
  • Carpopedal spasms
  • Tetany
  • Seizures
  • Steatorrhea
  • Prolonged QT interval
  • Rickets
  • Poor nail growth
  • Papilledema
  • Calcifications of basal ganglia


  • Labs:
    • Albumin
    • Ionized calcium (iCa)
    • Parathyroid hormone (PTH)
    • Phosphorus
    • Magnesium
    • 25-OH vitamin D
    • 1,25-OH₂ vitamin D
    • Urine calcium/creatinine (UCa/Cr) ratio


  • Treat underlying cause
  • Give calcium
    • Mild-moderate hypocalcemia: oral calcium repletion
    • Severe hypocalcemia: IV calcium
      • Can cause cardiac arrest if administered too rapidly
      • Ideally administered centrally as extravasation can cause tissue necrosis
        • Calcium gluconate safer than calcium chloride for peripheral IV infusion
  • Give vitamin D if indicated
  • Replace magnesium if hypomagnesemic
  • Be aware that calcium and/or vitamin D can cause hypercalciuria