High Blood Calcium

General or Other | Hematology | High Blood Calcium (Symptom)


Hypercalcaemia is an elevated calcium level in the blood. (Normal range: 9–10. 5 mg/dL or 2. 2–2. 6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a workup should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased intestinal calcium absorption, or decreased renal calcium excretion.


One of the most common causes of high calcium levels (hypercalcemia), is an overproduction of parathyroid hormone, or hyperparathyroidism. Hypercalcemia can occur due to other medical conditions. These conditions can vary in severity and chronicity, and may be life-threatening. Malignancy is a common cause of elevated blood calcium. Up to 20% of individuals with cancer will develop hypercalcemia at some point in their disease.

In the majority of patients with hypercalcemia, the signs and symptoms are minimal. In general, the symptoms increase with higher levels of calcium in the blood. In severe cases, the elevated calcium levels can cause abnormal heart rhythms with specific findings on electrocardiogram.

Symptoms are more common at high calcium blood values (12. 0 mg/dL or 3 mmol/l). Severe hypercalcaemia (above 15–16 mg/dL or 3. 75–4 mmol/l) is considered a medical emergency: at these levels, coma and cardiac arrest can result. Medical staff will recognise that panic attacks and hyperventilation cause hypocalcaemia and irritable, hypersensitive nerves with muscle cramping and tingling sensations. Hypercalcaemia causes the opposite - the high levels of calcium ions decrease neuronal excitability, which leads to hypotonicity of smooth and striated muscle. This explains the fatigue, muscle weakness, low tone and sluggish reflexes in muscle groups. In the gut this causes constipation. The sluggish nerves also explain drowsiness, confusion, hallucinations, stupor and / or coma.