Patient Education - Endocrine Encyclopedia
Endocrine Surgery Encyclopedia
Hypercalcemia is an excessive amount of calcium in the blood.
Causes, incidence, and risk factors:
Calcium is important in the body. It is an important part of the bone, and it exists as a
charged particle called an ion in the blood and inside cells. Calcium is important to many
body functions including bone formation, muscle contraction, nerve and brain function, and
the release of hormones.
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 from exposure of skin to sunlight, and from dietary sources such as
fortified dairy products, egg yolks, fish, and fortified cereals.
Primary hyperparathyroidism is the most common cause of hypercalcemia and is due to excess
PTH. The drug lithium, used in treating bipolar disorder, may increase PTH release and cause
hypercalcemia. A genetic mutation that affects the body's ability to regulate calcium is
seen in familial hypocalciuric hypercalcemia (FHH), a benign (non-cancerous) condition.
Blood calcium can also be high despite low levels of PTH, however. Some malignant tumors
(for example, lung cancers, breast cancer) produce PTH-related peptide (PTHrP) which increases
blood calcium. Excess vitamin D (hypervitaminosis D) from diet or inflammatory diseases can
also cause hypercalcemia. Kidney failure, adrenal gland failure, hyperthyroidism, prolonged
immobilization, use of a class of diuretics called thiazides, and ingestion of massive amounts
of calcium (milk-alkali syndrome) are other potential causes.
Hypercalcemia affects from 0.1 to 1% 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 be hypercalcemic,
usually due to primary hyperparathyroidism.
- Bone pain
- Loss of height
- Bowing of the shoulders
- Spinal column curvature
- Pathological fractures
- Flank pain
- Frequent urination
- Frequent thirst
- Poor appetite
- Memory loss
- Muscle twitches
- Muscle atrophy
Signs and tests:
- High serum total and/or ionized calcium
- High serum PTH level (hyperparathyroidism)
- High urine calcium (hyperparathyroidism, other causes)
- Low urine calcium (FHH)
- High vitamin D level (hypervitaminosis D, granulomatous diseases)
- High serum PTHrP (certain cancers)
Treatment is directed at the underlying cause of hypercalcemia whenever possible. In cases
of hyperparathyroidism, surgery may be needed to remove the abnormal parathyroid gland and
cure the hypercalcemia.
When hypercalcemia is mild and caused by primary hyperparathyroidism, patients may be
followed closely by their doctor over time. A new medication named cinacalcet has been shown
to lower calcium levels in the blood by reducing parathyroid hormone production.
Severe hypercalcemia causing symptoms and requiring hospitalization is treated aggressively
with the following:
- Intravenous fluids
- Bisphosphonates (drugs that stop bone breakdown and absorption by the body, such as
pamidronate or etidronate)
- Glucocorticoids (steroids, for hypervitaminosis D that is not medication-related)
- Hemodialysis (for hypercalcemia that is unresponsive to treatment and is life-threatening)
Prognosis depends on the underlying cause of hypercalcemia. Patients with mild hyperparathyroidism
or hypercalcemia with a treatable cause (for example, primary hyperparathyroidism, dietary
hypervitaminosis D) may not suffer complications from hypercalcemia.
Patients with hypercalcemia secondary to conditions such as cancer or granulomatous disease
may have a poor prognosis due to the underlying disease itself rather than to the hypercalcemia.
The complications of prolonged hypercalcemia are uncommon today.
- Bone cysts
- Nephrocalcinosis (calcification of the kidney)
- Kidney stones
- Kidney failure
- Peptic ulcer disease
- Difficulty concentrating or thinking
Calling your health care provider:
Contact your physician or health care provider if you have a family history of hypercalcemia,
family history of hyperparathyroidism, or if symptoms of hypercalcemia occur.
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.
Hypercalcemia from calcium and vitamin D supplements can be avoided 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.
Review Date: 5/12/2006
Reviewed By: Robert Hurd, MD, Department of Biology, College of Arts and Sciences, Xavier
University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.
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