Hypocalcaemia

Low calcium levels in the blood serum

Aetiology

  • Chronic kidney disease
  • Congenital absence (DiGeorge syndrome)
  • Destruction (surgery, radiotherapy, malignancy)
  • Autoimmune
  • Hypomagnesaemia - calcium release from cells is dependent on magnesium
  • Idiopathic
  • Pseudohypoparathyroidism and pseudo-pseudohypoparathyroidism

Clinical presentation

Symptoms

  • Paraethesia - fingers, toes, perioral
  • Muscle cramps, tetany
  • Muscle weakness
  • Fatigue
  • Bronchospasm or laryngospasm
  • Fits

Signs

  • Chovesteks sign - gentle tapping over the facial nerve causes twitching of the ipsilateral facial muscles
  • Trousseau sign - inflation of the sphygmomanometer cuff above systolic pressure for 3 min induces tetanic spasm of the fingers and wrist
  • ECG - QT prolongation

Investigations

  • Low serum calcium
notion image

Management

Management of acute severe hypocalcaemia

  • IV calcium gluconate 10 ml, 10% over 10 mins (in 50ml saline or dextrose)
  • Calcium infusion (10ml 10% calcium gluconate in 100ml infusate, at 50 ml/h)

Long term

  • Calcium supplement >1-2g PO/day
  • Vitamin D
    • 1 alphacalcidol 0.5-1 mcg PO/day OR
    • Depot injection: cholecalciferol 300 000 units 6 monthly