When does calcium in blood pose a risk?

It is vital that there is some calcium in blood. We need it in our blood stream for lots of different things – chiefly, the developing of bones, the contraction of muscles and the secretion of hormones amongst many other jobs. However, the body works hard to regulate the level and 99% of the time our blood calcium levels remain at the right amount for the healthy function of our bodies. However, sometimes, for many different reasons, more or less calcium enters the blood than it should do and these can have serious consequences.

Today, we’ll look at what happens when there is too much calcium in the blood stream, a condition otherwise known as hypercalcaemia.

The normal range for calcium in the blood is 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L). Anyone who has blood calcium levels greater than 2.6 mmol/L is defined as having hypercalcemia. Those with a mild increase that has developed slowly typically have no symptoms.

In those patients with higher levels or rapid onset, symptoms may include abdominal pain, bone pain, confusion, depression, weakness, kidney stones, or an abnormal heart rhythm including cardiac arrest.

In most cases, the principles reason for higher blood calcium levels is due to primary hyperparathyroidism. There is a small chance that cancer may cause it too. Other causes include sarcoidosis, tuberculosis, Paget disease, multiple endocrine neoplasia (MEN), vitamin D toxicity, familial hypocalciuric hypercalcaemia, and certain medications such as lithium and hydrochlorothiazide. Diagnosis should generally include either a corrected calcium or ionized calcium level and be confirmed after a week. Specific changes may be seen on an electrocardiogram (ECG).

Treatment is usually quite easily arranged and normally involves an intravenous drip. More severe cases can result with a brief stay in hospital. Often, particularly in cancer patients, the intravenous drip will be a regular event, normally every four to six weeks, or whenever symptoms like confusion and tiredness appear.