Understanding the Parathyroid

What are the Parathyroid [para-THIGHroid] glands ?

Although they sound alike and are next to each other in the mid-lower neck, the functions of the thyroid and parathyroid glands are not the same. Normal parathyroid glands are quite small, only a few millimeters wide (about a tenth of an inch), and weighing only about 50 mg (well under an ounce!). There are typically four parathyroid glands; two on the left and two on the right. The parathyroid glands produce a hormone called parathyroid hormone, commonly known as PTH. PTH is responsible for controlling the calcium levels in our bodies. It works to keep our blood calcium level within the normal range. It does so by its effect on the bones, which store calcium; the intestines, which absorb calcium; and the kidneys, which excrete calcium. When our parathyroid glands are normal in size and are working properly, PTH levels increase slightly when our blood calcium level goes down, and decrease slightly when our blood calcium level goes up. This delicate balancing system keeps calcium in our bones and makes them strong and not as likely to break.

What is hyperparathyroidism ?

When the parathyroid gland(s) grow larger than normal, they can overproduce PTH in an uncontrolled fashion. This is what we call hyperparathyroidism [hieper-pa-ruh-THIGH-roid-is-m] (HPT). HPT affects 1/1,000 people overall, and is more common in women. Overgrowth of the parathyroid gland(s) is almost always benign [BEE-nine] (not cancerous). Too much PTH leads to high calcium levels in the blood, weakening bones and producing mild loss of bone called osteopenia [os-tee-oh-PEEN-nee-uh] or even severe loss known as osteoporosis [os-tee-oh-puh-ROH-sis]. When the bone loss is severe, bone breaks can occur with very little trauma. The excess calcium level in the blood is then filtered through the kidneys, which over time can lead to kidney stones, kidney damage, and even kidney failure. HPT can also cause other problems, including pancreatitis [pan-kree-uh-TITE-iss] (an inflamed pancreas, the organ that produces insulin and digestive enzymes), bone pain, muscle weakness, depression, memory loss, and trouble concentrating. Despite the common finding of high blood calcium and PTH levels, features of HPT from patient to patient may be quite varied. For example, one person with the condition may have kidney stones and normal bones, and someone else may have bone loss, but no kidney stones.

The following is a list of the most common featuresof hyperparathyroidism.

  • Bone loss (osteopenia and osteoporosis)
  • Kidney stones
  • Frequent need to urinate (up at night to the bathroom several times)
  • Stomach ulcers and chronic abdominal pain, constipation
  • Pancreatitis
  • Memory loss and difficulty concentrating
  • Bone and joint aches
  • Muscle weakness
  • Irritability
  • Chronic fatigue and low energy

It is important to keep in mind that there are many other medical conditions that can cause these signs and symptoms. So, we cannot always assume that all of the typical HPT symptoms in a patient with HPT due to PTH and high calcium levels. However, patients with HPT often note an improved sense of well-being when their condition is successfully treated.

How is hyperparathyroidism diagnosed ?

With typical cases of HPT, the blood calcium level rises only slightly and causes very few symptoms. That is why HPT is usually picked up on routine blood work, when a higher than normal calcium level is detected at a yearly physical in an unsuspecting patient. Other routes of detection include patients with osteoporosis or kidney stones who are tested for the condition. Rarely, blood calcium levels can become dangerously high, producing confusion, lack of energy, and finally even coma. Making the diagnosis of hyperparathyroidism is usually straightforward, with the measured calcium and PTH higher than normal. At the time of diagnosis, vitamin D levels are also usually checked, as vitamin D is important for maintaining calcium balance in our bodies.

How is hyperparathyroidism treated ?

The only known cure for hyperparathyroidism is surgery (removal of the overgrown parathyroid gland(s)). Once the diagnosis of HPT is made, the patient must talk with their doctor(s) and decide if surgery is the best course of action. If it is, neck scans are generally done to find out which of the four parathyroid gland(s) is overgrown, and where the suspected gland is located. In most cases, only one gland has enlarged. Once the neck scans are completed, the doctor and patient will review the results and discuss the surgical plan. Most often, the surgery only requires a small incision in the mid-lower part of the neck to remove the diseased/overgrown gland(s). Parathyroid surgery has changed a lot in the past 10-20 years. Neck scars are kept as small as possible and there are fewer chances for problems related to surgery. Most importantly, the overall cure rate is excellent, with the calcium and PTH levels typically returning to normal within a few days. Once the condition is corrected, the patient will then discuss with his/her endocrinologist [en-doh-cri-NA-lo-jist] and primary care doctor the need for long-term calcium and vitamin D supplements.

Dr. Pallotta is an Associate Professor of Medicine at Harvard Medical School and a Senior Physician at Beth Israel Deaconess Medical Center in Boston. She attended New York Medical College and did her residency at Metropolitan Hospital and the Bronx VA in New York. Dr. Pallotta subsequently became a research and clinical fellow at Yale before beginning her career as a clinical endocrinologist and teacher at Boston’s Beth Israel Hospital (BIH) in September 1967. At BIH (now the Beth Israel Deaconess Medical Center) she became the head of the Radioimmunoassay Laboratory and Director of the Endocrinology Clinic, where she continues to manage its largest practice

Dr. Stephen received her medical degree from Harvard Medical School and subsequently completed her general surgical residency at the Massachusetts General Hospital and an endocrine surgical fellowship at the Cleveland Clinic. She then joined the surgical staff at the Massachusetts General Hospital in the Division of Surgical Oncology. Her clinical practice is focused on the surgical management of patients with endocrine tumors and she is a member of the MGH Endocrine Surgery Unit, the highest volume center in the country focused on surgery of the thyroid, parathyroid, and adrenal glands. Her particular areas of clinical expertise are in minimally-invasive parathyroid surgery, the treatment of thyroid cancer, and laparoscopic adrenal surgery. She also performs in-office ultrasound and ultrasound-guided biopsies of thyroid nodules and parathyroid tumors.