Hypercalcemia is too much calcium in the blood.

Calcium is important to many body functions including:

• Bone formation
• Hormone release
• Muscle contraction
• Nerve and brain function

Parathyroid hormone (PTH) and vitamin D regulate calcium balance in the body. PTH is produced by the parathyroid glands -- four small glands located in the neck behind the thyroid gland. Vitamin D is obtained when the skin is exposed to sunlight, and from dietary sources such as:

• Egg yolks
• Fish
• Fortified cereals
• Fortified dairy products

Primary hyperparathyroidism is the most common cause of hypercalcemia and is due to excess PTH. This excess occurs due to an enlargement of one or more of the parathyroid glands.

Other medical conditions can also lead to hypercalcemia:

• Adrenal gland failure
• An inherited condition that affects the body's ability to regulate calcium (familial hypocalciuric hypercalcemia (FHH))
• A type of diuretic medication called thiazides
• Excess vitamin D (hypervitaminosis D) from diet or inflammatory diseases
• Hyperthyroidism
• Kidney failure
• Massive amounts of calcium in diet (milk-alkali syndrome)
• Not moving for long periods of time
• Some cancerous tumors (for example, lung cancers, breast cancer)

Hypercalcemia affects a very small percentage of the population. The widespread ability to measure blood calcium since the 1960s has improved detection of the condition, and today most patients with hypercalcemia have no symptoms.

Women over the age of 50 are most likely to have hypercalcemia, usually due to primary hyperparathyroidism.

Abdominal:

• Constipation
• Nausea
• Pain
• Poor appetite
• Vomiting

Kidney:

• Flank pain
• Frequent thirst
• Frequent urination
• Kidney stones

Muscular:

• Muscle atrophy
• Muscle twitches
• Weakness

Psychological:

• Apathy
• Coma
• Dementia
• Depression
• Irritability
• Memory loss

Skeletal:

• Bone pain
• Bowing of the shoulders
• Fractures due to disease (pathological fractures)
• Loss of height
• Spinal column curvature

• Serum calcium
• Serum PTH
• Serum PTHrP
• Urine calcium
• Vitamin D level

Treatment is directed at the cause of hypercalcemia whenever possible. In cases of hyperparathyroidism, surgery may be needed to remove the abnormal parathyroid gland and cure the hypercalcemia.

If your hypercalcemia is mild and caused by primary hyperparathyroidism, your health care provider will follow you closely over time.

Severe hypercalcemia that causes symptoms and requires a hospital stay is treated with the following:

• Calcitonin
• Dialysis
• Drugs that stop bone breakdown and absorption by the body, such as pamidronate or etidronate (bisphosphonates)
• Fluids through a vein (intravenous fluids)
• Glucocorticoids (steroids)

How well you do depends on the cause of hypercalcemia. Patients with mild hyperparathyroidism or hypercalcemia with a treatable cause (for example, primary hyperparathyroidism or dietary hypervitaminosis D) may not have complications.

Patients with hypercalcemia due to conditions such as cancer or granulomatous disease may not do well due to the disease itself, rather than to the hypercalcemia.

Gastrointestinal

• Hypertension
• Pancreatitis
• Peptic ulcer disease

Kidney

• Calcium deposits in the kidney (nephrocalcinosis)
• Dehydration
• Kidney failure
• Kidney stones

Psychological

• Depression
• Difficulty concentrating or thinking

Skeletal

• Bone cysts
• Fractures
• Osteoporosis

The complications of long-term hypercalcemia are uncommon today.

Contact your physician or health care provider if you have:

• Family history of hypercalcemia
• Family history of hyperparathyroidism
• Symptoms of hypercalcemia

Most causes of hypercalcemia cannot be prevented. Women over the age of 50 should see their health care provider regularly and have their blood calcium screened periodically.

You can avoid hypercalcemia from calcium and vitamin D supplements by contacting your health care provider for advice if you are taking supplements without a prescription.

Taniegra ED. Hyperparathyroidism. Am Fam Physician. 2004; 69(2): 333-9.

Carroll MF. A practical approach to hypercalcemia. Am Fam Physician. 2003; 67(9): 959-66.

Ariyan CE. Assessment and management of patients with abnormal calcium. Crit Care Med. 2004; 32(4 Suppl): S146-54.

Bringhurst R, Demay MB, Kronenberg HM. Hormones and Disorders of Mineral Metabolism. In: Kronenberg: Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 27.