Parathyroid Surgery Information
Background
Surrounding the thyroid are four small glands called parathyroid glands. They are not associated with the thyroid other than being neighbors. These glands are in charge of regulating calcium levels for the body. They work almost like the thermostat does for heat. When you want the temperature to be 72 degrees, you set the thermostat. A signal is sent to the furnace that then generates heat. When the target temperature is reached, a signal is sent back the thermostat that it is 72 and the furnace shuts off. Parathyroid glands work like this as well. When the body’s calcium levels fall low, a signal is sent to the parathyroid glands that the body needs more calcium. The parathyroid glands make a hormone called parathyroid hormone (PTH) that then affects the bones and kidney. The hormone takes calcium from the bones and pushes it into the blood stream. The kidneys are instructed to filter back more calcium. The calcium level increases. Then a signal is sent from the body to the parathyroid glands that it has enough calcium and the glands shut off.
Except for 1/500 people whose thermostat breaks! In the case of the example, now it is 100 degrees in the room and the furnace is still going full speed. In cases of parathyroid pathology, the glands continue to make parathyroid hormone continuously and the calcium level rises.
- High calcium + low PTH = expected response to high calcium
- Low calcium + high PTH = expected response to low calcium
- High calcium + high PTH = parathyroid problem
Interestingly, parathyroid problems can affect one, two, three, or all four glands.
Symptoms of Parathyroid Problems
The obvious issue with parathyroid pathology is the bones. As calcium is flowing from the bones to the blood, the bones become thinner leading to osteopenia and osteoporosis. The kidneys are more prone to calcium stone formation. The joints, particularly the hips, ache and muscles hurt. Some patients note abdominal pains. There can be some psychological effects as well to include short term memory loss, attention deficits, and difficulty with calculations. Most patients, and their doctors, often explain away the symptoms to other issues. The main reason to correct the problems is for the bones. Bone disease is often ignored as there are no symptoms—until a major fracture.
How is the abnormal parathyroid identified?
Parathyroid glands initially develop from tissue behind the ear. As you develop as an embryo, the glands descend down along the carotid artery to rest around the thyroid. There are two glands on each side of the thyroid. The upper gland is usually located behind the thyroid and the lower gland is more anterior resting just off the lower pole of the thyroid. However, just like soldiers parachuting out of an airplane, parathyroid glands can blow off course. Sometimes, parathyroid glands can hide in the sheath that surrounds the carotid. Sometimes, the parathyroid glands are in the mediastinum, which is the top part of the chest. Sometimes, parathyroid glands can be inside the thyroid, under the esophagus, or really anywhere in the neck.
Previously, the surgery was done by standard exploration. The surgeon would pick their favorite parathyroid gland and dissect until they found it. A decision would be made if it was normal or abnormal, with this process repeated for all four glands. A normal parathyroid gland is about 5-6 mm and soft, yellow, and fatty. An abnormal gland is firm, discrete, and usually larger than 10 mm. The downside to this approach is that it is time consuming. There is some increased operative risk given the amount of dissection. This approach also often misses the unusually located glands if there are any.
Now, ultrasound is used preoperatively. Normal parathyroid glands are so fatty that they do not show up on ultrasound, but abnormal parathyroid glands do. The ultrasound can show exact location and size. Ultrasound is also useful as it can show if there are any problems with the thyroid. It is useful for a patient (and surgeon) to know beforehand if there is a reason to need concurrent thyroid surgery such as large goiter or thyroid cancer.
In the event that ultrasound does not show the location of the abnormal gland, a test called Sestamibi is used. This is an IV chemical that is injected and then accumulates in abnormally functioning parathyroid glands. A special camera is then used to identify any areas that light with the chemical. The Sestamibi scan is very much like a satellite flying over the desert looking for campfires. It shows as dots of light but is not as specific as an ultrasound or CT. CT is rarely used but can be of help with glands deep in the chest.
Sometimes, all of the tests do not reveal the location of the abnormal gland. This does not mean that the diagnosis is wrong. Usually, it points to a situation where all of the glands are affected. The analogy is that instead of a felon, there is a gang of four juvenile delinquents. None are bad enough to stand on their own, but exert a cumulative effect. Sometimes, the studies just are not helpful and the gland or glands are found in the OR just the same.
How many parathyroid glands do you need?
The minimum is 0.5. To go back to the original comparison, if you remove all of the parathyroid glands, then the furnace goes out. You are responsible then for heating the house. In the event that all four glands are abnormal, a balance is created by taking enough tissue to cure the problem but leaving enough tissue so that the body functions normally.
Documenting cure in the operating room
The operation is the final performance after the initial homework of blood tests, ultrasound, and sometimes Sestamibi. The half life of parathyroid hormone in the blood is remarkably fast. It takes about 10 minutes for one half (or 50%) to pass. In other words, if the PTH level is 100, then it should be 50 in 10 minutes. The surgeon is able to measure the PTH both before and 10 minutes after removing the abnormal glands. In addition to seeing a 50% decrease in PTH, with clinical cure, the levels will fall entirely normal in a short amount of time. When the levels are normal, the patient is cured.
The operation
The operation is done under general anesthesia through a small incision on the neck. Once the parathyroid gland (s) are removed and the PTH levels are normal, the incision is sealed with water proof glue. Most patients recover for a few hours and then go home same day with no restrictions.
Risks
As with all operations, there is inherent risk in surgery. Patients are observed in recovery for bleeding (neck hematoma). The nerves that control the vocal cords run underneath the thyroid and are in close proximity to the parathyroid glands. When operating around a nerve, there is a chance for injury to the nerve causing hoarseness or weakness to the voice. That risk is very small. There is also a chance, particularly in patients with all negative localization studies, of not finding the gland that is causing the problem. Preoperative preparation is important.
Low calcium
Following correction of parathyroid problems, the bones can then take calcium for themselves. Calcium moves from the blood back into the bones. Sometimes this happens gradually but sometimes it happens quickly. It is similar to taking a hungry man to an all you can eat buffet. If the bones are too hungry, it can cause the blood calcium to fall temporarily low. Symptoms of low calcium after thyroid surgery include numbness and tingling of fingers and around lips. It can progress to numbness in other parts of the body and also include muscle cramps and contractions. If problems are going to occur, they happen within the first 72 hours after surgery. If you don’t have problems by then, you probably will not. Severe cramping or problems breathing require an ED visit.
If your calcium is low post op, it is imperative that you take the following regimen until directed otherwise:
- At minimum, Calcium + Vit D 2 tablets with meals and before bed
- TUMS 2 tablets every hour if numbness or tingling persist
- Take calcium with orange juice as the acid helps to break down calcium
- Avoid diet soda as the phosphoric acid leaches calcium from the bones
- Magnesium supplements 2 tabs (800 units) daily will help with calcium absorption as well as the constipation that calcium can cause
- An extra Vit D supplement (at least 1000 units) daily will also help
- It is not unusual to require 20-40 calcium tabs daily until the parathyroid glands adjust—you cannot overdose!
Follow up
There is no wound care. Follow up is primarily to make sure that the body’s calcium level remains normal. If there was bone disease prior, repeat testing may be done months following to document improvement. Many people notice feeling better in both body and mind after surgery!