Hypercalcaemia refers to elevated calcium level in blood (normal range 2.2–2.6 mmol/L) that occurs in 10–20% patients with advanced cancers (most commonly in cancer of the breast, kidney, lung, prostate, head and neck and multiple myeloma)
Signs and Symptoms
• Symptoms of hypercalcaemia include nausea, vomiting, constipation, polyuria and disorientation
• Psychiatric overtones (depression 30–40%, anxiety, cognitive dysfunction, insomnia, coma)
• Clinical evidence of volume contraction secondary to progressive dehydration may be apparent. Severe hypercalcaemia (above 3.75–4.0 mmol/L) is a medical emergency and a poor prognostic sign
• Specific biochemistry like PTH,
• ECG to detect arrhythmias and
• Imaging with Bone Scan or PET–CT scan to identify metastatic bone disease.
- Treat the hypercalcaemia first and the cause later:
• Hydration & dieresis: 1–2 litres of isotonic saline (NS) over 2 hours with 30–40 mg of furosemide expands intravascular volume and enhances calcium excretion.
In elderly and cardiac patients, rate of hydration needs to be slower.
• Bisphosphonates–via a complex mechanism inhibit osteoclast and in turn both normal and pathological bone resorption. Commonly used bisphosphonates are:
• Zolendronic acid infused as 4mg in 100 mls of NS over 15 mins.
Normalisation of serum calcium occurs in 4–10 days and lasts 4–6 weeks. Therefore, if re–treatment is required, dose is repeated after 7 days
• Ibandronate 6 mg as 2 hour infusion or 50 mg (PO) daily
• Pamidronate 90 mg IV over 1–2 hours
• Bisphosphonates and Denosumab cause increasing risk of osteonecrosis of jaw following extraction of teeth or oral surgical procedures. Therefore, a dental review may be necessary to make sure the necessary dental procedures are completed prior to commencing therapy.
• Calcitonin – a thyroid hormone given 4–8 IU/kg IM or SC every 6–8 hours can bring about a rapid decline in calcium levels, however tachyphylaxis limits its utility.
5 Novemba 2020 12:53:19