The parathyroid glands are the smallest organs of the human body, located on anterior side of the neck, just behind the thyroid gland. Parathyroid glands keep blood calcium levels within the normal range. The level of blood calcium is decrease when the parathyroid glands hypofunctioning (hypoparathyroidism) and the level of blood calcium is increase when the glands hyperfunctioning (hyperparathyroidism). Both situations cause severe complaints and dysfunctions in many organs, particularly the heart, kidney, and vascular structures.
Masses originating from any tissues are called tumor. There are two types of tumors: benign and malignant. Tumors may be a few milimeters or tens of centimeters.
Parathyroid tumors usually do not exceed a few centimeters and are often undetectable with physical examination because they are trapped between the muscles of the neck.
The other name of benign parathyroid tumors are adenoma. Fortunately, 95% of parathyroid tumors are benign, not cancer. Benign tumors never spread to the surrounding tissues via direct invasion or blood and lymphatic vessels.
Other name for malignant parathyroid tumors are parathyroid cancer. They’re very rare. When a mass is diagnosed in parathyroid tissue, the probability of being malignant does not exceed 5%. Malignant parathyroid tumors are generally not locally aggressive and metastatic so life threatened effects are related to very high blood calcium levels. This is the major difference of malign parathyroid tumors and the other organ malign tumors. Long term high blood calcium levels may cause contractile disorders in the heart muscle and sudden cardiac arrest.
Benign and/or malignant parathyroid tumors are involves a single parathyroid gland, while the other three glands are healthy. In parathyroid hyperplasia, the disease involve all four glands but parathyroid hyperplasia is not a tumor it is only increasing of the number of cells in the gland. In the operation, surgeon must find the all four glands (which is a difficult task) and have to resect three of them.
Yes, chronic renal failure is the most common cause of parathyroid hyperplasia. Chronic renal failure cases often need to hemodyalysis. The time of hemodyalysis is related to risk of hyperplastic evolution of the parathyroid glands. The mechanism is not clear but calcium escape from the kidney to the urine is thought the main factor.
A 3-4cm long incision is made in front of the neck. The surgeon’s work is more difficult than adenoma surgery. Because in adenoma surgery, it is enough to find only one parathyroid gland but in the hyperplasia surgery, surgeon must find all four glands. Moreover, since the glands are enlarged according to hyperplastic transformation, they moved to different places. In this situation the operation turns into looking for a needle in a haystack!
As previously mentioned parathyroid adenoma is a benign tumor of the parathyroid gland. The radiological tests (ultrasonography, scintigraphy, etc.) are used routinely before the surgery, for localization of the adenoma. If the adenoma localized the operation is easy to perform. A 3-4cm long incision is made on the anterior region of the neck and the adenoma is removed easily. The time of the operation is short and the recovery of the patient is quick.
However, if the adenoma localization cannot be detected with preoperative radiological tests, the surgeon’s work is difficult. The surgeon must work patiently with kind manupilations. Expand the neck incision may be necessary and the time of operation getting two or three hours. Somehow the experienced surgeons find the adenoma but there is no guarantee!
The calcium level elevation in blood is quite insidious. Hypercalcemia may not display any signs for months, even years. Moreover, the findings are common and can be seen in many diseases: weakness, exhaustion, pain in the entire body, especially in the arms and legs. The most concrete finding in these patients is stones or sand in the kidney but this signs does not occur in every patient. Despite all, the diagnosis of hypercalcemia is not difficult: elevated calcium and parathormone levels in the blood are diagnostic.
The main task of calcium in the human body is muscle contractions. In order for the muscles to contract, calcium must enter the muscle cells. When the calcium is too much in the blood (hypercalcemia), they pass into the cell with high amounts and the muscles get contracted for a long time. The long time contraction of muscles is cause serious pain. The kidney tries to remove excess calcium in the blood. This causes the kidney damage and/or kidney stones.
The principal risk of hypercalcemic cases is acute heart attack. Too much calcium pass into the heart muscle cells causes more frequent and uncontrolled contractions, leading to heart failure and/or arrhythmia. These are the life-threatening situations.
When calcium is insufficient in the blood, the muscles cannot be contracted. Numbness and tingling in fingertips and lips are the main signs. There is also a serious loss of power in the body. Patients typically describe it as “I cannot lift my arm”.
The most common cause of low calcium level in blood is inapproprite thyroid surgery. Inapproprite thyroid surgeries cause the removal or damage of the parathyroid glands so immediately after the surgery hypocalcemia signs are appear.
It is a rare congenital disease, nearly 1% of all hypoparathyrodism cases. The cause of the disease may be related congenital parathyroid gland or parathormon receptor absences. The disease often manifests itself in adolescence with typical complaints of low blood calcium levels. Over the years the complaints are increase.
As previously mentioned, calcium is required to enter the cell to contraction of muscles. The muscles can not cantract sufficiently if blood calcium level is inadequate. Of course this situation most seriously effect in the heart muscle. If the heart muscle does not find enough calcium to contract, contractions are reduced. This is a serious problem that can lead to sudden cardiac arrest (acute heart attack).
After all kinds of parathyroid surgeries (malignant tumor, adenoma, hyperplasia) there are some complaints of sudden decrease of blood calcium level: numbness, tingling in finger tips and lips. The grade of the complaints varies depending on the height of the blood calcium and its duration in the preoperative period. However, all complaints disappear within a few days.