Acute severe hypocalcaemia

Acute severe hypocalcaemia can cause tetany, laryngospasm and seizures. Depending on the severity of associated seizures, hypocalcaemia can be life-threatening; arrange immediate transport to hospital by ambulance for management in a high-dependency ward. In children, acute severe hypocalcaemia can cause neuronal damage and intellectual impairment if left untreated.

Severe symptomatic hypocalcaemia of any cause should be treated initially with a slow intravenous injection of calcium. In adults, this is followed by a continuous intravenous calcium infusion. In children, the slow intravenous injection can be repeated as required; calcium infusions are not usually used in children. The goal is to control symptoms by maintaining the serum calcium concentration within the normal range.

Extravasation of calcium can cause localised skin necrosis; ensure intravenous access is secure and monitored. Calcium gluconate is preferred to calcium chloride as it is less toxic to peripheral veins. Calcium should never be administered by intramuscular or subcutaneous injection.

Note: Extravasation of intravenous calcium can cause severe tissue damage.

The parenteral calcium formulations available in Australia are:

  • calcium gluconate 0.22 mmol/mL1, available as a 10 mL vial containing 2.2 mmol of calcium
  • calcium chloride 0.68 mmol/mL (10%), available as a 10 mL vial containing 6.8 mmol of calcium.

For an adult, use:

1 calcium gluconate 0.22 mmol/mL1 4.4 mmol (20 mL) in sodium chloride 0.9% 100 mL intravenously over 20 minutes; repeat if required hypocalcaemia, acute severe (adult)    

FOLLOWED BY

calcium gluconate 0.22 mmol/mL1 22 mmol (100 mL) in sodium chloride 0.9% 900 mL (to achieve 1000 mL of a 0.022 mmol/mL solution) by intravenous infusion at an initial rate of 1.1 mmol/hour (50 mL/hour of diluted solution). Titrate to maintain a corrected serum total calcium concentration of 2.0 to 2.3 mmol/L    

OR

2 calcium chloride 0.68 mmol/mL (10%) 3.4 mmol (5 mL) in sodium chloride 0.9% 100 mL intravenously over 20 minutes; repeat if required hypocalcaemia, acute severe    

FOLLOWED BY

calcium chloride 0.68 mmol/mL (10%) 20.4 mmol (30 mL) in sodium chloride 0.9% 970 mL (to achieve 1000 mL of a 0.02 mmol/mL solution) by intravenous infusion at an initial rate of 1.02 mmol/hour (50 mL/hour of diluted solution). Titrate to maintain a corrected serum total calcium concentration of 2.0 to 2.3 mmol/L.    

For a child, use:

calcium gluconate 0.22 mmol/mL1 0.11 mmol/kg up to 4.4 mmol (0.5 mL/kg up to 20 mL), diluted in sodium chloride 0.9%, intravenously over 30 to 60 minutes; repeat as required. hypocalcaemia, acute severe (child)

Measure serum calcium concentration every 3 to 4 hours, and monitor cardiac function for the duration of intravenous therapy.

Once the patient is stable and can tolerate oral intake, start an oral calcium supplement. If hypocalcaemia is caused by severe vitamin D deficiency or hypoparathyroidism, or if hypocalcaemia is difficult to control with the infusion, also start oral calcitriol (an active vitamin D compound). See Moderate hypocalcaemia for calcium and calcitriol doses. The infusion can be stopped once adequate oral therapy has been established.

It may be necessary to correct coexisting hypomagnesaemia (see Hypomagnesaemia), especially in patients with:

  • severe postoperative hypoparathyroidism
  • malabsorption due to short bowel syndrome
  • hypocalcaemia associated with alcohol abuse
  • proton pump inhibitor–induced hypomagnesaemia.

Long-term therapy may be necessary if the cause of hypocalcaemia is permanent (eg damaged parathyroid gland); see Long-term management of hypocalcaemia.

1 Calcium gluconate 0.22 mmol/mL solution for injection is also referred to as 931 mg/10 mL solution for injection. It was previously known as calcium gluconate 10%.Return