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Hypercalcaemia


What is it?

A raised level of corrected* calcium in the blood.

*TOTAL plasma calcium is the combination of free, ionised calcium and protein-bound calcium. If the albumin level is low, protein bound calcium is low. This may mask a high concentration of free, ionised calcium. Calcium is therefore 'corrected' for albumin level.

Why is it important?

1. It may cause symptoms. These do not always relate to the level of serum calcium.

Common symptoms are:

2. It may cause pain, or make existing pain worse.

3. It may cause dehydration, coma and cardiac arrest.

How common is it?

What sort of cancer produces hypercalcaemia?

Hypercalcaemia of malignancy is caused by the secretion of a PTH-like substance by the tumour. Contrary to popular belief, it can occur in the absence of bone metastases. Conversely, patients can have widespread bone metastases and remain normocalcaemic.

What is the significance of hypercalcaemia?

It usually indicates disseminated disease (74%). 95% of patients with breast cancer and hypercalcaemia have disseminated disease. 61% of patients with lung cancer and hypercalcaemia have disseminated disease.

There are only four cases in the world literature of a cure in the presence of malignant hypercalcaemia; Hypercalcaemia usually means a very poor prognosis - 4/5 of patients die within a year.

Treatment

Treatment is aimed at improving wellbeing and symptoms for symptomatic patients for weeks or even months. The treatment of choice is an intravenous bisphosphonate infusion (Pamidronate). Zoledronic acid is even more potent. Before treatment, the following need to be considered:

Treatment is usually simple and well tolerated. Sometimes transient flu-like symptoms occur which respond to oral Paracetemol. A typical dosing schedule for Pamidronate is given below.

Corrected Serum Calcium mmol/l Pamidronate dose (mg)
3 15-30mg
3-3.5 30-60mg
3.5-4 60-90mg
>4 90mg

The dose is made up in 500mls of N saline and given over two hours. With appropriate supervision and training it can be given in day case units, community hospitals or in the home if nursing support is available.

It takes up to 3 days to start working and 5-7 days to exert its maximum effect. Patients who are very symptomatic, clinically dehydrated or with a calcium > 3.5 will need admitting for rehydration for 3 days while it takes effect. The dose can be repeated after a week if the initial response is inadequate. Zoledronic acid 4mg is as effective as pamidronate 90mg, can be given I/V over 5-10 minutes and response can last up to five weeks. This makes it advantageous in a primary care setting, but choice of bisphosphonate may depend on local guidelines and protocols.

How long does treatment last?

A single infusion will usually maintain normocalcaemia for three weeks. Hypercalcaemia tends to recur. Consider monitoring the serum calcium weekly and ensure the patient and family know the symptoms to watch for. Pamidronate infusions can be repeated every three -four weeks according to the serum calcium. There is no evidence that oral bisphosphonates prevent further episodes of hypercalcaemia and they are poorly tolerated.

Key Points

Useful Links

North of England cancer network guidelines hypercalcaemia of malignancy - PDF file

Lothian Palliative Care guideline on hypercalcaemia of malignancy - PDF file

© Dr. Eileen Palmer, Dr John Howarth Palliative Care for the Primary Health Care Team (2004) Quay Books ISBN 1856422291

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