The four parathyroid glands, each about the size of a pea, are found on the back surface of the thyroid gland in the neck. They produce parathyroid hormone (PTH), which helps the body maintain the right balance of calcium and phosphorous. If the parathyroids make too much PTH, blood calcium levels rise, and calcium stored in bone is depleted. It isn't unusual for abnormally high blood levels of calcium to show up in screening tests even in people who appear healthy and have no symptoms. The most common cause of this problem is a benign tumor on one or more of the glands. When severe, this condition (hyperparathyroidism) can lead to loss of calcium from bones and bone weakening, kidney stones, kidney damage, and mild to marked mental and emotional changes.
I discussed your question with my colleague Seymour Reichlin, M.D., Ph.D., an endocrinologist and retired research professor of medicine at the University of Arizona. He says there is no satisfactory medical treatment for hyperparathyroidism. For that reason, surgery is nearly always recommended. Today's scanning methods allow surgeons to identify the size and location of the abnormal parathyroid glands and remove them with only minor risks of complications.
Treatment is trickier when patients do not show any signs of excess parathyroid hormone activity ("asymptomatic" hyperparathyroidism). Dr. Reichlin said that in 1991, a group of specialists meeting under the auspices of the National Institutes of Health agreed that individuals over the age of 50 with this condition could safely defer surgery as long as they have periodic evaluations of their bone density and kidney function. If either worsens, surgery is indicated. A study published in the August 2007 issue of the Journal of Clinical Endocrinology & Metabolism showed that bone density did not decline in most patients who followed this plan. However, similar patients who did have the surgery showed a small but significant increase in bone calcium, and perhaps more importantly, an improvement in general health and vitality.
Dr. Reichlin concludes that the pros and cons of surgery for asymptomatic hyperparathyroidism in patients over age 50 are still up for discussion. Specialists in internal medicine usually deal with diagnosis and management of hyperparathyroidism, but Dr. Reichlin recommends that you consult a clinical endocrinologist to get additional advice.
Andrew Weil, M.D.