54. Alterations of the Parathyroid Function

Question 1

what is the function of Parathyroid

Answer 1

The parathyroid glands are small endocrine glands located in the neck, usually four in number, and situated behind the thyroid gland. They play a crucial role in regulating calcium and phosphate levels in the body. The main hormone produced by the parathyroid glands is called parathyroid hormone (PTH)

Question 2

Parathyroid Hormone (PTH) Production and Function

Answer 2

PTH helps regulate calcium and phosphate levels in the blood through its effects on the bones, kidneys, and intestines. When blood calcium levels are low, the parathyroid glands release PTH, which acts on the following organs:

Bones: PTH stimulates the release of calcium from bones into the bloodstream, helping to increase blood calcium levels.

Kidneys: PTH acts on the kidneys to reduce calcium excretion and increase phosphate excretion, promoting the reabsorption of calcium back into the bloodstream while eliminating excess phosphate through urine.

Intestines: PTH indirectly enhances the absorption of dietary calcium in the intestines by stimulating the production of activated vitamin D, which facilitates calcium absorption.

Question 3

what are the parathyroid disorders

Answer 3

1) Hyperparathyroidism
a) Primary Hyperparathyroidism (due to tumour
b) Parathyroid Hyperplasia ( all four glands effected
c) Secondary Hyperparathyroidism (compensatory response)

2) Hypoparathyroidism

Question 4

explanin the pathophysiology of parathyroid disorders

Answer 4

Hyperparathyroidism:
a) Primary Hyperparathyroidism: The most common cause of primary hyperparathyroidism is the development of a benign tumor called a parathyroid adenoma in one of the parathyroid glands. This adenoma continuously produces excess parathyroid hormone (PTH) independently of calcium levels in the blood. This leads to increased calcium reabsorption from the bones, increased calcium absorption from the intestines, and reduced calcium excretion by the kidneys. As a result, blood calcium levels rise (hypercalcemia).

b) Parathyroid Hyperplasia: In some cases of primary hyperparathyroidism, all four parathyroid glands may become overactive and enlarge, a condition called parathyroid hyperplasia. The exact cause of parathyroid hyperplasia is unclear, but it is thought to involve genetic factors, abnormal signaling pathways, or changes in the regulatory mechanisms of the parathyroid glands.

Secondary Hyperparathyroidism:
Secondary hyperparathyroidism is a compensatory response to conditions that cause chronic low calcium levels or vitamin D deficiency. The underlying causes can include chronic kidney disease, vitamin D deficiency, malabsorption disorders, or inadequate calcium intake. In these cases, the parathyroid glands respond to low blood calcium levels by increasing the production and release of PTH. The elevated PTH levels stimulate increased calcium release from the bones, enhanced absorption of calcium in the intestines, and decreased calcium excretion in the urine. However, this compensatory response becomes excessive over time, leading to persistent high levels of PTH and disturbances in calcium and phosphate homeostasis.

Hypoparathyroidism:
Hypoparathyroidism occurs when there is insufficient production or secretion of parathyroid hormone (PTH) by the parathyroid glands. The most common cause of hypoparathyroidism is accidental damage or surgical removal of the parathyroid glands during thyroid surgery. Autoimmune disorders, genetic disorders, or low magnesium levels can also contribute to hypoparathyroidism.
In hypoparathyroidism, the decreased production of PTH leads to reduced calcium reabsorption from bones, decreased calcium absorption from the intestines, and increased calcium excretion in the urine. As a result, blood calcium levels decline (hypocalcemia), and phosphate levels may increase (hyperphosphatemia). The reduced calcium levels affect various organ systems, leading to symptoms such as muscle cramps, tingling or numbness, seizures, and abnormal heart rhythms.
Treatment for hyperparathyroidism depends on the underlying cause. In primary hyperparathyroidism, surgical removal of the affected parathyroid gland or glands may be necessary. In secondary hyperparathyroidism, treatment involves addressing the underlying condition, such as vitamin D supplementation or managing chronic kidney disease. Hypoparathyroidism is managed by replacing calcium and vitamin D, often in the form of medications, to maintain adequate calcium levels in the blood.
Regular monitoring of calcium, phosphate, and PTH levels is crucial in the management of parathyroid disorders to ensure appropriate calcium metabolism and prevent complications.