Hypercalcemia

What is Hypercalcemia?

Calcium is an important minerals in your body. It is regulated by hormones (Calcitriol and parathyroid hormone) and the kidneys. Hypercalcemia means your body has a higher amount of calcium than usual. This is a common condition in patients with cancer, with incidence as high as 30%.

Which cancer types are more commonly causing high calcium in my body?

The types of cancers that are more commonly causing hypercalcemia are:

• Lung cancer
• Breast cancer
• Bone cancer
• Cancer of the head and neck region
• Oesophageal cancer
• Kidney cancer
• Prostate cancer
• Cancers that have spread to the bones
• Hematological malignancies, e.g. lymphomas and multiple myelomas

Symptoms of hypercalcemia can be very non-specific. You may just feel a bit unwell or tired. More, the severity of your symptoms may not match with the level of calcium in your blood.

Some of the symptoms of hypercalcemia include:

• feeling more tired than usual
• loss of appetite
• loss of concentration or interest
• constipation
• low mood or increase in irritability
• feeling thirsty
• passing urine more than usual
• dry mouth
• nausea and vomiting
• drowsiness or confusion
• muscle spasms
• palpitation or irregular heartbeat

If you have severely high calcium level, you might also have seizures or difficulty in muscle movement.

How to diagnose hypercalcemia?

Your doctor will check the calcium level in your blood by a blood test to confirm the diagnosis. You may also have an echocardiogram (ECG) to check for any arrythmia. Further blood tests including renal function, phosphate and potassium levels may also be checked during treatment.

How to treat hypercalcemia?

Treatment depends on the severity of the hypercalcemia. Your doctor may prescribe the following treatments:

1. Intravenous fluid: Your doctor may give intravenous fluid through a drip to reduce the calcium level in your blood. You can also drink plenty of water to reduce the calcium level.
2. Bisphosphonate (e.g. pamidronate, zoledronic acid): These drugs reduce the bone breaking and are given by infusion. They can also reduce pain due to bone metastasis.
3. Denosumab: Denosumab is a human monoclonal antibody that prevent bone breaking down and help to restore the bone health. It is commonly used in patients with bone metastasis or the hypercalcemia cannot be controlled with bisphosphonate.
4. Calcitonin: Your doctor may inject calcitonin, which is a kind of hormone that regulate the calcium level in your body. It can be given several times a day.
5. Steroid: If you have hypercalcemia due to hematological malignancies, steroid may be given to lower the calcium level.

Other general measures include:

• Taking medications that relieve symptoms like nausea, vomiting, constipation or pain.
• Stopping medications that may increase risk of hypercalcemia, e.g. diuretics, calcium supplements, tablets for dyspepsia or reflux
• Limiting food and supplement rich in calcium level, e.g. milk, vitamin D supplements

Special thanks to Mr. Ryan Kwok (Class M26), medical student of Li Ka Shing Faculty of Medicine, the University of Hong Kong, and Dr. Wendy Wing-Lok Chan, Department of Clinical Oncology, the University of Hong Kong for authoring and editing this article.