Parathyroid 101

The parathyroid glands are four very small glands that are found in the lower neck. The four glands sit near the thyroid (two on the right and two on the left), but otherwise they are not related to the thyroid in any way. The parathyroid glands help to control the amount of calcium we have in our blood. The glands produce parathyroid hormone (PTH), which tells our kidneys and intestines to hold on to calcium and in turn increases the amount of calcium found in our blood. PTH also activates our bones to release calcium into the blood as well. Normally the parathyroid glands produce the appropriate amount of PTH to keep our body’s calcium levels within a normal range.

The main problem we see related to the parathyroid glands is a disorder called primary hyperparathyroidism. In this condition, one of the four glands become overactive and produces parathyroid hormone whether we need it or not. This increase in PTH can in turn cause elevated calcium levels (hypercalcemia). Symptoms related to this condition can include osteoporosis, kidney stones, bone and joint pain, fatigue, nausea, forgetfulness, and overall malaise (just feeling bad). Often a work up for this condition is started when a patient is found to have elevated calcium levels on routine blood work. Subsequently a PTH level will be checked and found to be elevated as well. If primary hyperparathyroidism is suspected then additional studies may be ordered in attempts to identify which of the four glands is overactive. Initially an ultrasound of the neck can be performed. Parathyroid glands are normally so small they cannot be seen on ultrasound. If the gland becomes overactive it often enlarges and can be seen on ultrasound. If the overactive gland cannot be identified this way, then a nuclear medicine parathyroid scan can be performed. If an overactive gland is identified then the main treatment is surgery to remove the overactive parathyroid gland. Normally only the one overactive gland is removed, leaving three normal glands behind. Three glands are enough to maintain normal PTH and calcium levels.

The other main causes of hyperparathyroidism are normally found in patients with chronic renal (kidney) failure. The kidneys lose their ability to retain calcium and too much calcium is lost in the urine. This causes low calcium levels in the blood, which causes the parathyroid glands to kick into overdrive. This often results in all four glands being overactive and is a much more difficult problem to treat. If it becomes severe often three and one-half glands are removed surgically.

Hypoparathyroidism, or low levels of parathyroid hormone, is a condition occasionally seen after someone has had their entire thyroid gland removed. Sometimes during surgery to remove the thyroid all four parathyroid glands become irritated or injured. When this occurs the glands temporarily (or rarely permanently) stop producing parathyroid hormone. This in turn causes hypocalcemia or low levels of calcium in the blood. This is often treated by placing patients on a calcium supplement and another medication that helps the body absorb calcium. The initial symptoms on hypocalcemia are often numbness or tingling around the lips or fingertips.

If you have concerns about hyperparathyroidism you may want to talk to your PCP about having her parathyroid hormone and calcium levels checked. If they verify a parathyroid related problem, then referral to an otolaryngologist (ENT) is recommended.