written by: Emma Lloyd
• edited by: Leigh A. Zaykoski
• updated: 12/20/2009
Diseases of the parathyroid cause overproduction or underproduction of parathyroid hormone, which can lead to severe imbalance in calcium levels. Many parathyroid disease symptoms are related to this calcium imbalance.
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The parathyroid glands are located behind the thyroid, and are named for their location next to this gland. Despite the name, the function of the parathyroid glands is not related to the thyroid; instead, the main role of these glands is to regulate blood calcium levels. When blood levels of calcium drop too low, the parathyroid glands secrete parathyroid hormone. This has the effect of promoting calcium breakdown in bones, to release calcium into the bloodstream for use by cells.
Parathyroid hormone also activates vitamin D in the gut, to increase absorption of dietary calcium in the gastrointestinal tract, and promotes uptake of calcium in the kidneys.
Most incidences of parathyroid disease involve overproduction of parathyroid hormone, leading to raised blood calcium levels. If this secretion is caused by a defect of the gland itself, such as cancer, the disease is called primary hyperparathyroid disease. When it is caused by another factor unrelated to parathyroid function, it is called secondary hyperparathyroid disease.
Calcium plays a crucial role in the nervous system, and blood calcium levels are carefully regulated to provide enough calcium for nervous function. When parathyroid hormone is overproduced blood calcium levels can become dangerously high, leading to parathyroid disease symptoms such as fatigue, weakness, depression, anxiety, nausea, vomiting, and digestive disorder. Long term effects can include kidney stones, cognitive impairment. In addition osteoporosis risk is greatly increased because increased parathyroid hormone levels increase the amount of calcium absorbed from the bones into the bloodstream.
When parathyroid hormone is underproduced, the disease is called hypoparathyroidism. This disease is less common than hyperparathyroidism, but the potential consequences are more severe. Hypoparathyroidism symptoms can include muscle cramps, cataracts, muscle spasms, breathing difficulty, and seizures. Bones are not affected in this disease, however. Hypoparathyroid disease causes include trauma to the parathyroid glands, autoimmune disease, and magnesium deficiency.
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Diagnosis and Treatment of Parathyroid Disease
Diagnosis of parathyroid diseases is made on the basis of blood tests for parathyroid hormone, calcium, and phosphate. Other tests may be carried out to assess the level of damage the disease has done to other parts of the body, such as the bones. After diagnosis, the patient’s condition is monitored with regular blood tests for calcium, phosphorous, phosphate, vitamin D, bone density, and serum albumin, depending on the disease involved.
Treatment for parathyroid diseases involves both immediate and long-term treatment to manage the symptoms. In addition the underlying cause of the disease must be treated.
Severe hypoparathyroidism is a potentially fatal disease, and is generally treated as soon as possible after diagnosis. Initial treatment involves administration of intravenous calcium to immediately restore safe blood calcium levels. Long term treatment includes supplements of calcium and Vitamin D. Synthetic parathyroid hormone is a treatment option for some people.
In the case of hyperparathyroidism, long-term management of side effects such as osteoporosis must be considered in addition to treatment of the disease itself. If surgery is not necessary the patient is monitored with regular blood tests, and is also counseled on dietary modifications to regulate calcium levels.
In some cases, when the cause of the disease is cancer, the tumor may be removed while leaving the glands intact. Often the most effective treatment is to remove the parathyroid glands; in these cases the patient must afterwards take supplemental calcium and vitamin D to prevent dangerously low blood calcium levels.