Low calcium levels
This page is about low calcium levels (hypocalcaemia) in people who have cancer. There is information about
Hypocalcaemia (pronounced high-po-kal-seem-ee-ah) means a low calcium level in the blood. It is rare in people with cancer. It can be a temporary side effect of some cancer treatment drugs, such as cisplatin and doxorubicin.
The main cause of low calcium levels is having the parathyroid glands in your neck removed. This may be necessary for some types of cancer in the neck area. Or it can occur if the parathyroid glands are damaged during thyroid gland surgery. This affects up to 5% of people after thyroid surgery. The parathyroid glands can also be damaged during other types of surgery to the head and neck. After head and neck surgery, you may have permanently low calcium levels or they may go back to normal after a few months.
The parathyroid glands help to keep a steady level of calcium in the blood. We have 4 parathyroid glands in the base of our necks. They are tiny and close to the thyroid gland. The position of the glands makes it difficult for a surgeon to remove the thyroid without damaging or removing the parathyroid glands during the operation.
The parathyroid glands make parathyroid hormone (PTH). Normally when the level of calcium in the blood drops, the parathyroid glands make more PTH. This increases the amount of blood calcium by making
- The bones release calcium into the blood
- The kidneys take more calcium back into the blood when urine is being made
- The intestines absorb more calcium from food
If the parathyroid glands have been removed or damaged, your body won’t produce enough PTH. This is called hypoparathyroidism (pronounced high-po-para-thi-royd-ism).
You can find out more about the body and calcium in this section.
Many people don’t have any symptoms when their calcium levels are low. After surgery for thyroid cancer, your surgeon will check your blood calcium levels before you leave hospital. You will also have regular check ups and these include blood tests to check your calcium levels. So your doctor may tell you that you have hypocalcaemia before you have any symptoms.
Symptoms of hypocalcaemia include
- Painful muscle spasm and cramps
- Twitching of muscles
- Numbness or tingling in feet and hands
- Numbness or tingling around the mouth
If hypocalcaemia is not found and treated, you can get more severe symptoms, such as
- Dry skin
- Fits (seizures) – this is very rare
If you have any of these symptoms talk to your doctor.
If your blood calcium level is low, your doctor will prescribe calcium and vitamin D tablets for you. This usually keeps your blood calcium at a normal level. Eating foods with high levels of calcium will also help.
If you have sudden symptoms of hypocalcaemia after head and neck surgery, you will need to have calcium directly into the blood through a drip (intravenous infusion). If you have hypoparathyroidism there is a helpful organisation called Hypoparathyroidism UK, who offer information and support.
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