Hypercalcaemia

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Hypercalcemia is a common metabolic disorder affecting up to one third of cancer patients.
Malignant causes include osteolysis, dehydration and humoral hypercalcemia of malignancy,
Non-malignant causes include primary hyperparathyroidism, dehydration, tuberculosis, sarcoidosis, certain medications (e.g. Lithium) , and excessive Calcium/ Vit D supplements.
It occurs either in the presence of skeletal metastases or in their absence in patients who have humoral hypercalcemia of malignancy.
It is a poor prognostic indicator in malignant disease.

Corrected Calcium (measured calcium corrected to serum albumin levels)
- Hypercalcaemia is defined as corrected calcium levels of ≥2.6mmol/L
Urea and Electrolytes
- Dehydration and electrolyte imbalance is common in hypercalcaemia

Principles of treatment include weighing the potential benefits versus burden of therapy taking into considerations patient’s disease trajectory as well as goals of care.
Rehydration
- Rehydration is most important. It helps to restore renal function and increase calcium excretion
- Most patient have fluid deficits of 4 to 6L. Hydrate with 2 to 3L of IV fluids per day if there are no contraindications
Bisphosphonates
- Ensure adequate hydration before starting intravenous bisphosphonate
- Dose reduction is required in renal impairment (see table below)
- Dose can be repeated 7 days after the initial dose
- Common side effects include transient fever and myalgia
- Patients with poor dentition or recent dental issues may need dental clearance especially if on high doses and long duration of use, which increases risk of osteonecrosis of the jaw.
Calcitonin
- 4 units/kg twice a day up to a maximum of 8units/kg Q6H for not more than 3 days in view of tachyphylaxis, which can occur after 48 hours.
- Drops calcium level by 0.3 to 0.5mmol/L
- Rapid onset via subcutaneous route ≈2 hours
- Generally used when corrected calcium >3.5mmol/L to reduce calcium levels while awaiting bisphosphonate and hydration to take effect.
Denosumab
- Considered as efficacious as bisphosphonates for hypercalcemia
- Can be used in renal failure without dose adjustment.

Scotland. Scottish Palliative Care Guidelines. (2021). Hypercalcaemia. https://www.palliativecareguidelines.scot.nhs.uk/guidelines/palliative-emergencies/Hypercalcaemia.aspx
Watson,M.,Lucas, C., Hoy, A., Wells, J. (2009). Oxford Handbook of Palliative Care (2nd ed.). Oxford Uni. Press.
Shane, E., Berenson, JR. (2020). Treatment of hypercalcemia. https://www.uptodate.com/contents/treatment-of-hypercalcaemia?search=hypercalcemia%20ofmalignancy%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1