Urgent considerations

See Differentials for more details

In an emergency setting, serum calcium level can be used to determine the urgency with which hypercalcaemia should be corrected.[10] Irrespective of the presence or absence of symptoms, hypercalcaemia above 3 mmol/L (12 mg/dL) warrants urgent treatment.

Those with calcium levels >3.5 mmol/L (14 mg/dL) are at high risk for dysrhythmia and coma. Severe symptoms and coma are unlikely when calcium is <3.25 mmol/L (<13 mg/dL). Patients with calcium levels between 3.0 and 3.5 mmol/L (12-14 mg/dL) may tolerate the increased calcium well if the level has risen slowly over a period of time, but are usually symptomatic and will require prompt correction.

Calcium levels above 3.25 mmol/L (13 mg/dL) are more common in patients with malignancy-associated hypercalcaemia.[18]

Hypercalcaemia may present with aggressive metabolic bone disease with fractures and bone pain. Calcium and parathyroid hormone (PTH) should be measured and should reveal the likely diagnosis.

Severe hypercalcaemia

May present with profound lethargy or coma in the emergency department. Measurement of calcium and an ECG are required as part of the evaluation of any semiconscious patient. Markedly elevated calcium and shortened QT interval require urgent treatment and the electrolyte abnormality can be further investigated when the patient is stabilised.

  • In cases of coma, the following investigations are recommended: calcium and electrolytes, glucose, urea, haematocrit, and an ECG. Calcium levels should be >3.25 mmol/L (>13 mg/dL) to explain coma.[10] Hypercalcaemia may be a part of dehydration and not the direct or immediate cause of the diminished consciousness.

Initial treatment includes:[10][19]

  • Hydration with 0.9% sodium chloride to dilute calcium levels, 4-6 litres administered over 24 hours. Monitor for fluid overload in renal impairment and older patients

  • Intravenous bisphosphonates to inhibit osteoclast activity. Monitor serum calcium response, nadir reached after 2-4 days. Dose reductions may be considered in those with renal impairment.

  • Calcitonin to inhibit osteoclast activity and enhance urinary excretion of calcium, given under specialist supervision if poor response to other measures.

Routine use of a loop diuretic in the management of severe hypercalcaemia is not recommended.[10] Use of loop diuretics should be restricted to patients who develop fluid overload while receiving aggressive volume resuscitation. Dialysis may be considered in severe renal failure.[10]

Denosumab, a human monoclonal antibody that inhibits osteoclast formation, may be considered for PTH-related hypercalcaemia.[19][20]

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