Approximately 99 percent of the calcium in the body is found in the bones. The remaining 1 percent is distributed in the blood and body tissues. The Linus Pauling Institute at Oregon State University notes that the calcium levels in the blood must remain within very small ranges for the body to function properly. When excess calcium accumulates in the blood, the condition is referred to as hypercalcemia.
Physiology
Two hormones, the parathyroid hormone and calcitonin, regulate the levels of calcium in the blood. When blood calcium levels fall below normal, the parathyroid glands release parathyroid hormone to trigger the release of calcium from the bones into the bloodstream. When calcium levels get too high, the thyroid gland releases calcitonin, which hinders the release of calcium from the bones and allows blood calcium levels to fall. When there is a problem with either of these body processes, calcium levels in the blood are able to accumulate.
Causes
The most common cause of hypercalcemia is a condition called primary hyperparathyroidism, according to Medline Plus. This condition is characterized by the release of excess amounts of parathyroid hormone by the parathyroid glands. Other causes include failure of the adrenal glands, hereditary disorders, hyperthyroidism, kidney failure, certain medications and cancerous tumors. Occasionally, hypercalcemia may be caused by excess intake of calcium through the diet.
Symptoms
Symptoms of hypercalcemia usually develop gradually. MayoClinic.com notes that mild hypercalcemia may not cause any symptoms at all. Some potential symptoms of hypercalcemia include nausea, vomiting, loss of appetite, increased thirst, increased urination, constipation, muscle pain, joint pain, abdominal pain, muscle weakness, confusion and fatigue.
Treatment
Initial treatment for hypercalcemia focuses on restoring blood calcium levels to normal. In many cases, this requires hospitalization. During hospitalization, you will be given intravenous fluids, diuretics, calcitonin and other medications. Dialysis may also be required to flush out the blood without putting excess strain on the kidneys. Once blood calcium levels return to normal, further treatment depends on the specific underlying cause of the hypercalcemia.
Complications
If left untreated, hypercalcemia can cause damage to several different organs and organ systems. The release of calcium from the bones can lead to osteoporosis, which is characterized by brittle, weak bones prone to breakage. High blood calcium levels can also cause the development of kidney stones or result in kidney failure. Some people with hypercalcemia develop abnormal heart rhythms, called arrhythmias, or experience impaired nervous system function.
