Hypoparathyroidism
Hypoparathyroidism is a rare condition in which the parathyroid glands fail to produce sufficient amounts of parathyroid hormone or the parathyroid hormone produced lacks biologic activity. The parathyroid glands are part of the endocrine system, the network of glands that secrete hormones into the bloodstream where they travel to various areas of the body.
These hormones regulate the chemical processes (metabolism) that influence the function of various organs and activities within the body. Hormones are involved in numerous vital processes including regulating heart rate, body temperature and blood pressure as well as cell differentiation and growth and also in modulation of several metabolic processes.
Parathyroid hormone (along with vitamin D and the hormone calcitonin, which is produced by the thyroid gland) plays a role in regulating the levels of calcium and phosphorus in the blood and in determining bone growth and bone cell activity. Due to a deficiency of parathyroid hormone, individuals may exhibit abnormally low levels of calcium in the blood (hypocalcemia) and high levels of phosphorus (hyperphosphatemia).
Hypocalcemia can cause a variety of symptoms including weakness, muscle cramps, excessive nervousness, headaches, and/or uncontrollable twitching and cramping spasms of certain muscles such as those of the hands, feet, arms, legs, and/or face (tetany). Numbness and tingling around the mouth and in the fingers and toes can also occur.
Two Types of Hypoparathyroidism:
- Deficient parathyroid hormone secretion
- Resistance to Parathyroid Hormone (Pseudo-hypoparathyroidism)
Cause or causes of hypoparathyroidism and its types
Surgery: The most common cause of hypoparathyroidism is damage to or removal of the parathyroid glands due to surgery for another condition. Hypoparathyroidism may result from removal of or damage to the parathyroid glands or their blood supply. Surgeries such as:
- Removal of part or all of the parathyroid glands in hyperthyroidism
- Surgery to treat goiter or hyperthyroidism
In such cases, hypoparathyroidism may be temporary (transient in 75% of cases) depending upon the extent of the damage. Transient post-surgical hypoparathyroidism can become permanent (25% of cases). Post-surgical hypoparathyroidism may occur shortly after surgery or appear months to years later. When hypoparathyroidism occurs due to external factors such as surgery, these cases are sometimes referred to as acquired hypoparathyroidism.
Low levels of magnesium(hypomagnesemia) : Low magnesium levels can affect the function of your parathyroid glands. Normal magnesium levels are required for normal production of parathyroid hormone. This is often called functional hypoparathyroidism because it resolves when magnesium is restored. One common cause of low levels of magnesium in the body is chronic alcoholism. Other causes of hypomagnesemia include malnutrition, malabsorption, diabetes, chronic diarrhea, certain kidney disorders, and the use of certain medications.
high levels of magnesium (hypermagnesemia): Less often, hypoparathyroidism can be caused by abnormally high levels of magnesium (hypermagnesemia) in the blood. Magnesium can activate the CASR protein on the parathyroid chief cells (hormone-secreting cells) and inhibit the secretion of parathyroid hormone. Hypermagnesemia can be occur when magnesium accumulates because of impaired kidney function or when magnesium is given as a therapy as in tocolytic therapy (which is given to women to suppress preterm labor).
Extensive cancer radiation treatment of your face or neck: Radiation can result in destruction of your parathyroid glands. In rare cases, radioactive iodine treatment for hyperthyroidism may lead to hypoparathyroidism.
Congenital hypoparathyroidism insufficiency: refers to infants who are born without parathyroid tissue, the ability to make parathyroid hormone, or with parathyroid glands that do not function properly. Congenital hypoparathyroidism that occurs during the first few months of life may be temporary (transient) or permanent. In some patients, the cause of hypoparathyroidism is unknown (idiopathic). Congenital hypoparathyroidism may also occur in infants whose mothers have hyperparathyroidism. As opposed to “hypo”-parathyroidism, “hyper”-parathyroidism results in excessive calcium levels in the bloodstream. In a pregnant woman, the excess calcium may cross the placenta reaching the developing fetus and suppress fetal parathyroid hormone production by the growing infant’s parathyroid glands.
DiGeorge syndrome: is a disease in which hypoparathyroidism occurs because all the parathyroid glands are missing at birth. This disease includes other health problems besides hypoparathyroidism. It is usually diagnosed in childhood.
Autoimmune disease: In some cases, your immune system attacks parathyroid tissues as if they were foreign bodies. In the process, the parathyroid glands stop producing their hormone.
Familial hypoparathyroidism: Hereditary or familial parathyroid insufficiency is often associated with other endocrine diseases, such as adrenal insufficiency, and is present in first-degree relatives and family members.
References
https://medlineplus.gov/ency/article/000385.htm
https://www.mayoclinic.org/diseases-conditions/hypoparathyroidism/symptoms-causes/syc-20355375
