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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). There are several causes of high blood calcium levels, but a common cause is because an abnormal parathyroid gland tumor produces too much hormone .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. Low levels of calcium may cause anxiety, numbness, muscular cramps, heart rhythm abnormalities, and seizures. 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 or malabsorption), calcium levels drop in the blood. Parathyroid glands sense the low calcium levels and increase hormone production which causes bone to dissolve and blood calcium levels to increase. 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. Most often, PTH levels and calcium levels are both high which indicates parathyroid disease. If calcium levels are high or in the high-normal range and PTH levels are normal, a parathyroid adenoma is usually still the cause. A very common scenario, however, is fluctuation of the PTH and calcium levels. In patients with a parathyroid tumor, a blood calcium levels between above 10.0 pG/mL is common. Our bodies prefer to be around 9.5. The diagnosis of parathyroid disease is made by laboratory tests.

Other tests

Laboratory testing is standard and should include a CMP (comprehensive metabolic profile), 25 Hydroxy Vitamin D, Phosphorus, Alkaline phosphatase, and a Dexa Bone scan. Urine studies are not routine but can be helpful in some cases.

Hyperparathyroidism

The most common cause for high blood calcium levels is a parathyroid adenoma. This condition is not common, but it is not rare. Adenomas are benign tumors that produce too much hormone. The adenoma no longer regulates calcium 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 percent of people, one adenoma is present and the other three parathyroid glands are normal. The remaining 15 percent have more than one abnormal gland, often all four.

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.

Ultrasound

An ultrasound of the neck and thyroid is performed because it can identify an adenoma in many patients. It is also helpful because about 20 percent of patients with parathyroid disease also have thyroid disease and if a thyroid nodule is found, it may be biopsied or treated. Many times an ultrasound is performed by the hospital or an endocrinologist, but is best to have the ultrasound performed by the surgeon who will perform the surgery so they can determine the exact location of the adenoma and plan surgery. MRI scans may show an abnormal gland but the test is expensive and the yield is low.

Parathyroid scan

A parathyroid scan is a test in which a radioactive molecule called technetium is given as an injection into a 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 higher 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 because their activity is suppressed by the high levels of calcium in the blood. 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. Parathyroid scans are not used to diagnose the condition. They will not do this. Many people with parathyroid tumors have normal scans and this should not deter a patient from having their condition treated. With my fourteen years of experience in Utah County (American Fork Hospital, Utah Valley Regional Hospital, Timpanogos Hospital, and Central Utah Radiology), about 60 percent of the scans in patients who actually have an adenoma are positive. In the 40 percent of patients with a non-localizing scan, many of these patients have multiple abnormal glands or the abnormal gland is small or located under the thyroid, or thyroid nodules which also take up the tracer confuse the study.

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.

NM Parathyroid Scan

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

TREATMENT

The only curative treatment for primary hyperparathyroidism is surgery. The critical step is finding a surgeon with experience. Most graduates of an otolaryngology-head and neck surgery program are trained to remove parathyroid tumors. Many surgeons will perform surgery but most do not treat a high volume of patients. 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 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 about 40 percent of people. 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 long surgical procedure. A standard parathyroid procedure should take about an hour if a blood test for parathyroid hormone is obtained during surgery.

MINIMALLY INVASIVE PARATHYROID SURGERY

Surgery is possible with local anesthesia/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 also and a patient is typically not aware of the procedure. If a general anesthetic is used, intra-operative monitoring of the nerve which controls voice is often used in order to reduce the chance of injury.

The ability to obtain parathyroid hormone levels rapidly (10 minute wait, 20 minute processing time) has improved parathyroid surgery. Since the life of parathyroid hormone is about 2 to 3 minutes, hormone levels will drop rapidly after an abnormal gland has been removed. Ten minutes after excision of the tumor, parathyroid hormone levels should be normal in most patients. For patients with multiple abnormal glands, PTH levels will not drop to normal. Confirmation of normal hormone levels improves the success rate of surgery because failure to restore normal PTH levels indicates the presence of additional abnormal glands.

Another development is localization of the abnormal adenoma before surgery. Ultrasound, parathyroid scans, and 4D CT are all used to localize parathyroid adenomas. Parathyroid scans do not show precise anatomy of the neck but they are helpful, because the surgeon may know which side to begin, but it does not tell exactly where the tumor is located. CT and ultrasound may indicate the precise location of the adenoma. Localization may be possible with an intra-operative radio-probe using a miniature Geiger counter probe, but this technique, although promoted by some surgeons, has not proven to be reliable and is not used in major surgical centers.

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).

Incision for surgery

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

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

NIM Monitor

SURGERY

Surgery to remove an abnormal gland requires dissection to the thyroid gland and then lifting the thyroid to gain access to its undersurface. Parathyroid glands are usually located in the area between the esophagus and trachea. The parathyroid glands are often next to the laryngeal nerve and care is required to remove them without harming the nerve. Once the adenoma is defined, and the nerve has been identified and protected, the adenoma may be removed. Blood for PTH levels is drawn after 10 minutes. Even if hyperparathyroidism was thought to be caused by one abnormal adenoma, it is often best to examine both glands on the side where the adenoma is present, as this may help to confirm that the gland is truly normal. This may be done while waiting for the blood test which takes 20 minutes. If hormone levels return to normal, the incision may be closed. If blood levels still indicate abnormally high PTH levels, and the other parathyroid gland on the same side was normal, the parathyroid glands on the opposite side of the neck need to be examined.

All abnormal glands need to be removed in order to cure the condition. If all four glands are abnormal (15 percent of all patients), it is common to remove three and one half glands and leave some functional tissue, or remove all four glands and implant some of the parathyroid tissue into a muscle with easy access. Tissue is left because if all glands are removed, a patient will be dependent upon calcium pills and will need to take them twice a day or more for life. Parathyroid tissue is left in a muscle because the blood supply to muscle is typically good and the gland will survive and function, and if the gland grows and calcium levels increase, another operation may be required and it is easier to remove the extra tissue from a muscle compared to deep in the neck because there is a risk of harming a laryngeal nerve.

AFTER SURGERY

After surgery most patients have a mild degree of 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 soon after surgery as calcium returns to normal. Many patients report increased energy and begin to understand that prior vague symptoms of malaise have resolved.

Low calcium levels

Symptoms begin with tingling of the face in the region around the mouth and nose. Generalized weakness and increased numbness and tingling occur as calcium levels become lower. Nerves become more excitable and if calcium levels become too low, seizures and heart rhythm abnormalities may also occur. It is common to take calcium supplements after parathyroid surgery. If one gland was removed, the other three glands will function, but the body may require days to weeks to adjust to the normal calcium levels. If all four parathyroid glands were abnormal, typically three or three and a half glands will be removed and it is more common to have a period of low calcium after surgery. Calcium supplements will be required.

Voice changes

The laryngeal nerves are near the parathyroid glands and can be harmed during surgery. If the nerve are bruised or stretched, a temporary change in voice will occur and over several weeks the voice will recover. If the nerve is cut, the vocal cord on the affected side will be paralyzed. Procedures are available to improve the voice, but the voice will never be normal.

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