THE PARATHYROIDS

THE PARATHYROIDS

The Parathyroids:

Background:The four parathyroid glands are located at each of the four corners of the thyroid gland and secrete parathyroid hormone into the blood circulation. Parathyroid hormone maintains normal concentration of calcium in blood by regulating absorption of calcium from the kidneys, bone, and gut and maintains normal concentration of phosphate in blood by regulating excretion of phosphate in the kidneys. Parathyroid hormone is necessary for maintenance of bone structure and normal bone mineral content.

Reduced Parathyroid:The four parathyroid glands are located at each of the four corners of the thyroid gland and secrete parathyroid hormone into the blood circulation. Parathyroid hormone maintains normal concentration of calcium in blood by regulating absorption of calcium from the kidneys, bone, and gut and maintains normal concentration of phosphate in blood by regulating excretion of phosphate in the kidneys. Parathyroid hormone is necessary for maintenance of bone structure and normal bone mineral content.

Symptoms: Lower than normal concentration of parathyroid hormone in blood may cause low calcium and high phosphate concentrations in blood. It may lead to increased nerve conduction, muscle spasms and muscle cramps. Low concentration of calcium in blood may affect heart function and may cause cataract, mental irritability, fatigue, and depression. If present for a longer period of time it may lead to increased bone density and kidney stones. A low concentration of the protein that caries calcium in blood may give an impression of low calcium concentration while the concentrations of free calcium and the parathyroid gland function are actually normal .

Diagnosis: Low function of the parathyroid glands is diagnosed by simultaneous measurement of calcium, phosphorous, and parathyroid hormone in blood.

Treatment: Reduced function of the parathyroid glands is treated by calcium and vitamin D as tablets. Treatment by synthetic parathyroid hormone has the advantage of correcting the increased bone density, but must be dministered as an injection.

Increased Parathyroid Function:

Higher than normal secretion of parathyroid hormone is the result of autonomous function of the parathyroid glands. It occurs most often with older age. I may also be the consequence of kidney failure.

Symptoms: Increased secretion of parathyroid hormone stimulate absorption of calcium from the gut, and decrease the excretion of calcium in the kidneys resulting in increased calcium concentration in the blood. Increased parathyroid production will increase phosphate excretion by the kidneys leading to a decrease of blood phosphorous. It may cause decreasing kidney function and kidney stones. Increased production of parathyroid hormone stimulates absorption of calcium and phosphate from bone structures and may cause low bone mineral density with increased fracture risk. Abnormally high concentrations of parathyroid hormone in blood may reduce mental cognitive functions particularly in elderly patients.

Diagnosis: The first diagnostic sign of altered secretion of parathyroid hormone is often (80% of cases) an abnormal concentration of calcium in blood found at a routine health check-up. This will lead to a more specific diagnosis of altered parathyroid hormone production by measuring the concentration in blood of parathyroid hormone itself.

Treatment: Abnormally high production of parathyroid hormone may initially be treated by medically increasing the sensitivity of calcium receptors. It must eventually be treated by surgical removal of most of the parathyroid glands.
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