Hyperparathyroidism

There are two main types of hyperparathyroidism, primary hyperparathyroidism and secondary hyperparathyroidism.  The term "hyperparathyroidism" generally refers to primary hyperparathyroidism.

Primary hyperparthyroidism is most commonly caused by one or more of the parathyroid glands forming a tumor that secretes excessive parathyroid hormone. Over 95% of these tumors are benign.  Over 80% of the time this is from a single enlarged parathyroid gland.  This enlarged parathyroid gland tumor is called a parathyroid adenoma.  Rarely primary hyperparathyroidism is caused by parathyroid cancer.  Normal parathyroid glands stop secreting parathyroid hormon (PTH) in response to normal or elevated calcium levels in the blood.  The abnormal parathyroid adenoma does not "turn-off" in response to a normal or elevated calcium level in the blood stream and therefore continues to secrete PTH.  This in turn causes an elevated calcium level in the blood stream.

Symptoms of primary hyperparathyroidism include bone pain, osteoporosis (thin bones), kidney stones, and abdominal discomfort.  Osteoporosis is caused by excessive action of osteoclasts which are cells that break down bone tissue.  This in turn may lead to bone pain and even fractures.  Kidney stones are caused from excessive calcium in the kidney and urine.

Primary hyperparathyroidism is usually first suspected from having an elevated calcium level in the blood stream.  Usually either this elevated calcium level, kidney stones or osteoporosis lead to a further workup to rule out hyperparathyroidism.  The diagnosis of hyperparathyroidism is made when there is an elevated blood calcium level together with an elevated or high normal PTH.  Normal parathyroid glands are supressed with an elevated calcium level, however a parathyroid adenoma continues to secrete PTH despite an elevated calcium level.  This is how the diagnosis is ultimately made.  In almost all cases the recommendation is for surgery to remove the abnormal parathyroid adenoma.  There is no other medicine or treatment to cure primary hyperparathyroidism.

Secondary hyperparathyroidism is caused by medical conditions that cause low blood calcium levels.  In response to this low calcium level, the parathyroid glands react and produce PTH.  The PTH is elevated beyond the normal limits because the body is trying to increase the calcium levels in the blood stream.  Conditions that cause secondary hyperparthyroidism include vitamin D deficiency, kidney disease and calcium deficiency.  Treatment for secondary hyperparathyroidism is focused on correcting the underlying cause of the low calcium levels.  This usually includes vitamin D and calcium supplements.  Surgery is sometimes indicated, but not as often as seen with primary hyperparathyoidism where surgery is almost always indicated.