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HYPERPARATHYROIDISM

by DR. DOUGLAS DENYS, M.D., F.A.C.S.

Thyroid Surgeon, Head and Neck Surgeon, Facial Plastic Surgeon

Symptoms: Fatigue, tiredness, depression, anxiety, osteopenia-osteoporosis, body aches, kidney stones, heart arrhythmia, mental depression, and stroke.

All the above symptoms may occur in those who have increased levels of calcium in their blood (hypercalcemia). A common cause for hypercalcemia is because an abnormal parathyroid gland tumor produces too much hormone which causes bone demineralization and increased blood calcium. Treatment requires removal of the tumor.

Parathyroid glands

Parathyroid glands are small glands located in the neck near the thyroid gland. There are typically four glands each of which is about the size of an apple seed. Parathyroid glands are located under the thyroid gland but the precise location may be variable. Parathyroid glands may be located above the level of the voice box or inside the chest, but most of the time they are located near the thyroid gland. Parathyroid glands secrete parathyroid hormone (PTH) which regulates the concentration of calcium in our blood. Calcium is very important and promotes proper nerve conduction and function. If calcium levels are too high or too low, various symptoms occur. Elevated calcium levels often cause fatigue, weakness, depression, pain or aches in the body and extremities, kidney stones, depression, osteoporosis, and mood alteration. Very high levels may cause stroke or coma like symptoms. Osteoporosis is often seen in late stage disease but various levels of bone loss occurs in all with the disorder as the calcium used to increase blood levels comes from the bones. When calcium levels are too low, anxiety, numbness, muscular cramps, heart rhythm abnormalities, and seizures may occur. Low levels of calcium are typically due to kidney failure or as a complication of thyroid surgery when all parathyroid glands are removed. Hyperparathyroidism is the topic for this discussion.

Calcium

Calcium levels are affected by the kidney, parathyroid glands, and diet. Calcium is excreted by the kidney. Parathyroid hormone helps to break down bone to release calcium into the blood stream. Calcium is absorbed by the gut from foods we eat and is facilitated by Vitamin D. Dysfunction of the kidneys, parathyroid glands, or bone breakdown may affect blood calcium levels. When calcium absorption in the gut is too low (poor diet, malabsorption), calcium levels drop in the blood. Parathyroid glands sense the drop and produce more hormone so calcium levels may increase and stay in the normal range. This calcium is taken from our bones. If the kidney excretes too much calcium, PTH levels increase in the same way. In some cases a parathyroid gland is abnormal and produces too much hormone causing calcium to increase in the blood. In this case the balance is upset and blood calcium levels stay high, even though the kidney tries to excrete the extra calcium. When the cause of the condition is due to an abnormal parathyroid gland the condition is called hyperparathyrodism. This condition always causes bone loss and leads to osteoporosis.

DIAGNOSIS:

The most common indication of parathyroid disease is the finding of an elevated blood calcium level. This is often part of a routine blood test. Most patients when questioned have fatigue or other symptoms as mentioned above but may not be aware of them until after questioned or after surgical treatment of the condition. Some patients present with kidney stones and then are found to have high blood calcium levels. Another common presentation is after a fracture. Once high calcium levels are identified, parathyroid hormone levels are measured and are usually elevated, but may still be within the normal range. In the most common scenario, PTH levels and calcium levels are both high. A very common scenario, however, is fluctuation of the PTH and calcium levels. In patients with a parathyroid tumor, a blood calcium level between 10-11.0 is common. Our bodies prefer to be around 9.5. The diagnosis of the condition is made by laboratory tests.

Causes and work-up of hyperparathyroidism:

The most common cause for high calcium levels is a parathyroid adenoma. This is a benign tumor which produces too much hormone. The adenoma no longer regulates calcium well and blood levels increase. The other three parathyroid glands tend to become dormant and stop producing hormone because the abnormal gland is already producing too much hormone. In about 85% of people, one adenoma is present and the other three parathyroid glands are normal, although more than one adenoma can be present.

If a high blood calcium level and high PTH level is identified, it is almost always due to a parathyroid adenoma. If calcium levels are high or in the high-normal range and PTH levels are normal, a parathyroid adenoma is usually still the cause. It is common for PTH and calcium levels to vary. Most normal people maintain a relatively normal and stable calcium blood level.

The example below shows a laboratory result for a patient who had a single parathyroid adenoma who had symptoms of fatigue, tiredness, depression, and overall malaise. . Calcium levels were 11.2 (normal 8.4-10.4) and parathyroid hormone levels were 148 (normal 12-72).

Lab Result

Once hyperparathyroidism is diagnosed by laboratory testing, a parathyroid surgeon is consulted to remove the abnormal parathyroid gland. Once the gland is removed, the condition is resolved in a high percentage of people. Several other tests may be ordered to help plan surgery. Unfortunately many doctors may use these tests as diagnostic studies. Diagnosis is based on laboratory data, not images like MRI, ultrasound, or parathyroid scans. If the scans are negative it does not mean a parathyroid tumor is not present; in fact, in many patients this will result in a delay of treatment. A parathyroid scan is often used to help localize the gland.

Parathyroid scan: A parathyroid scan is a test in which a radioactive molecule called technetium is given as an injection into vein. The material will travel throughout the body but it is harbored in the salivary glands, thyroid glands, and parathyroid glands. The molecule will wash out of the glands at different rates and because an abnormal parathyroid tumor has a high density of cells and is larger than the other parathyroid glands, the amount of radioactivity will be higher in the tumor. The three other normal parathyroid glands usually are dormant anyway because there activity is suppressed by the high levels of parathyroid hormone produced by the tumor and don’t take up the molecule.

Example of a NM parathyroid Scan. The top images show activity immediately after injection of the radioactive material and the lower row shows activity after two hours. The first column is a front view, the middle images are with the head rotated to the right, and the third column is with head rotated to the left. The white spots in the lower neck are thyroid and parathyroid tissue. In the delayed images a focal spot is seen near the midline in the frontal view but with the rotated head views this shows a left side parathyroid adenoma scan.

NM Parathyroid Scan

On imaging, the abnormal gland will often light-up and can be seen on the image. This helps to show which of the four glands is abnormal so a minimally invasive surgery may be offered. In the above case, the left lower gland would be removed. Parathyroid scans are not used to diagnose the condition. They will not do this. Many people which parathyroid tumors have normal scans and this should not deter a patient from having their condition treated. In Utah County in my experience over ten years working with American Fork Hospital, Utah Valley Regional Hospital, Timpanogos Hospital, and Central Utah Radiology, about 60% of the scans are positive for an adenoma. This leaves over 40% of patients with a scan that does not localize.

Most abnormal parathyroid glands are about 1 to 2 cm in size and are ovoid in shape. Large tumors often produce higher levels of parathyroid hormone and may be more scar tissue holding them in the neck.

This is an example of a parathyroid adenoma in a patient who had a negative parathyroid scan. Pre-operative parathyroid hormone levels were 256 with calcium of 11.2:

Parathyroid Adenoma

Other tests:

An ultrasound of the neck may also be ordered but this is usually obtained to see if thyroid nodules or thyroid disease is present. Thyroid nodules may also need to be biopsied during the surgery and this permits better planning. It is common to have both thyroid nodules and parathyroid disease. MRI scans may show an abnormal gland but the test is expensive and the yield is very low. On rare occasion, urine calcium levels are measured to see if a rare genetic condition is present. Vitamin D, phosphorus, alkaline phosphatase levels may be ordered but they do not usually help to diagnose hyperparathyroidism.

TREATMENT

The only treatment for primary hyperparathyroidism is surgery. The critical step is finding a surgeon with experience. Many surgeons will perform surgery but most do not treat a high volume of patients because the condition is fairly rare. It has been well proven that the more experienced a surgeon has with thyroid and parathyroid surgery, the lower the surgical risk and the higher success rate. Dr. Denys trained a year longer than any other ENT surgeon in Utah County with an emphasis in Head and Neck surgery and has performed a high volume of thyroid and parathyroid surgery for ten years in Utah County and has a special interest in parathyroid surgery and thyroid surgery.

Surgical removal of the abnormal gland is typically curative but if not performed properly may leave you with a large scar, permanent voice change, swallowing abnormalities, and perhaps an untreated condition because the tumor was not found. This creates a problem for the next surgery, as it is often much harder to excise a tumor during revision surgery because the neck has scar tissue and the risk of harming the nerves which control voice is higher.

Modern parathyroid surgery is less invasive than standard surgery and is called minimally invasive surgery because a small incision is used-usually one inch or less and dissection is limited to the area of the abnormal gland/tumor. Parathyroid "exploration" is not preferred as all four glands are explored through a larger incision and much more dissection of the neck is required and the risk of complications is higher. Exploration implies that the gland location is not known. A surgeon with a lot of experience knows where the parathyroid glands are located and should not need to explore. The problem with parathyroid surgery is that the abnormal gland position may not be well known before surgery in the 40% of people, those with negative parathyroid scans. Some surgeons do not offer surgery in patients with negative parathyroid scans which is unfortunate because the patient will continue to have bone loss, osteoporosis, and have symptoms. Other surgeons may offer to explore the neck to look for the abnormal gland which may result in a very long surgical procedure. A standard parathyroid procedure should take less than an hour if a blood test for parathyroid hormone is obtained during surgery and the procedure may be shorter if blood tests are not obtained and gland removal is confirmed with radioactive counting.

MINIMALLY INVASIVE PARATHYROID SURGERY

Many people believe a small scar indicates minimally invasive surgery but nearly all parathyroid surgeries can/should be performed though a small incision (less than one inch). Dissection deep in the neck should also be minimal.

This is a typical incision used for parathyroid surgery. The incision was less than one inch and it was made in a natural crease line so as to minimize visibility. A small bandage was placed with a sterile waterproof cover to permit showering the day of surgery if desired.

Typical Incision

A few developments in medicine have improved parathyroid surgery. The ability to measure parathyroid hormone and gets results during the surgery is a major help. Since the life of parathyroid hormone is about 2 to 3 minutes, hormone levels will drop rapidly after the abnormal gland has been removed. Ten minutes after excision of the tumor, parathyroid hormone levels should be normal. Dr. Denys will often measure a pre-op level and a post-op level to confirm the condition has been cured. Some patients will have more than one adenoma and if only one tumor is removed, the levels will still be high and the condition will not be cured. Confirmation of normal hormone levels improves success. A parathyroid surgeon in Florida reports very fast surgical times, often less than 30 minutes, but hormone levels are not measured. In order to obtain parathyroid hormone levels, 30 minutes are required: Ten minute wait after removal of the tumor and another 20 minutes to get the results back. If the parathyroid tumor is tested with a radioactive probe, blood tests may not be needed but there is some risk that more than one adenoma is present and a second surgery may be required. I prefer to confirm PTH levels after excision of the tumor.

Another development is radioactive localization. The parathyroid scan is helpful as it may show the location of the abnormal tumor but it does not show precise anatomy of the neck. Usually a radiologist will read the image and report, "increased activity in the lower thyroid region" or "increased activity on delayed images on the right side." This is helpful, because the surgeon may know which side to begin, but it does not tell exactly where the tumor is located. These scenarios depend upon surgeon experience to find and remove the tumor. Localization may also be done with intra-operative radiotracer localization using a miniature Geiger counter probe. This permits identification in many patients with precision even if the parathyroid scan was negative. The technique can permit a small incision, direct dissection to the tumor, and removal. At present, Dr. Denys is the only surgeon who uses the radio-probe surgery at the American Fork Hospital. At a precise time prior to surgery, a dose of radioactive material will be injected and this will permit localization of the tumor.

This is a radiotracer system used to identify abnormal parathyroid gland tumors. The probe is the silver wand on the desk top.

Radiotracer System

Surgery may be offered under local anesthesia with sedation or with general anesthesia. The method depends upon patient fitness level and will be discussed during the pre-operative visit. If local anesthesia is used, sedation is given so injections are not felt. You will be semi-alert but comfortable throughout the surgery. If a general anesthetic is used, intra-operative monitoring of the nerve which controls voice will be used in order to reduce the chance of injury.

NIM monitor used during surgery to monitor recurrent laryngeal nerve, the nerve which controls the voice and larynx function.

NIM Monitor

After surgery most patients have little pain and may resume normal activities within a few days. A high percentage of patients will be discharged home the day of surgery as an outpatient. Calcium levels usually normalize within several hours. After surgery, a protocol for calcium supplementation is followed to help rebuild and replace bone density caused by the condition. Most patients will take calcium for up to two years. Most patients will feel better very soon after surgery as calcium returns to normal. Many report increased energy and begin to understand that prior vague symptoms of malaise have resolved.

Utah Ear Nose Throat

Douglas Denys M.D., F.A.C.S.

1159 E. 200 N., Ste. 325

American Fork, UT, 84003

(801) 855-2930 Fax (801) 855-2934