Hypercalcemia is a disorder of calcium homeostasis with an excessive amount of calcium in the blood/serum. It can have many causes including some as benign as eating or drinking excessive calcium or being on too high of a supplement of calcium to more in depth reasons like taking medications with hypercalcemia as a side effect or cancers that elevate calcium through numerous mechanisms.
Endocrinologists can evaluate and separate the many different causes of hypercalcemia and aid in treatment and resolution of these issues. One cause of hypercalcemia is of particular interest to Endocrinologists is hypderparathyroidism. Though the name may indicate multiple relationships, the thyroid gland and the parathyroid glands are only structurally related and have nothing to do with each other functionally. There are (usually) four parathyroid glands and they are immediately adjacent to the thyroid gland. Whereas the thyroid gland is involved in metabolism, the parathyroid glands are mainly involved in calcium homeostasis in the blood. The parathyroid glands mediate their activity through secretion of parathyroid hormone (PTH).
Excessive PTH results in increased calcium absorption from the gut as well as excessive calcium release from the bones. This can result in hypertension, osteoporosis, kidney stones, muscle pains and constipation. Excessive calcium can even result in cognitive effects such as confusion. Levels of PTH greater than 14 can even result in loss of consciousness.
Excessive parathyroid hormone is usually a result of excessive secretion by one (but sometimes more than one or rarely even all four) parathyroid gland (adenoma) which has become uncontrolled and secretes PTH independent of biochemical feedback. The recommended therapy is surgical removal of the adenoma. However, there are cases where medical therapy may be necessary, if the patient cannot tolerate surgery or localization of the abnormal gland is not possible.
Hypercalcemia is a complex topic that our Houston area endocrinologists see frequently to help our patients back to health and perhaps even off of some of their medications!
