hypoparathyroidism


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Related to hypoparathyroidism: hyperparathyroidism, pseudohypoparathyroidism

Hypoparathyroidism

 

Definition

Hypoparathyroidism is the result of a decrease in production of parathyroid hormones by the parathyroid glands located behind the thyroid glands in the neck. The result is a low level of calcium in the blood.

Description

Parathyroid glands consist of four pea-shaped glands located on the back and side of the thyroid gland. The gland produces parathyroid hormone which, along with vitamin D and calcitonin, are important for the regulation of the calcium level in the body. Hypoparathyroidism affects both males and females of all ages.

Causes and symptoms

The accidental removal of the parathyroid glands during neck surgery is the most frequent cause of hypoparathyroidism. Complications of surgery on the parathyroid glands is another common cause of this disorder. There is the possibility of autoimmune genetic disorders causing hypoparathyroidism such as Hashimoto's thyroiditis, pernicious anemia, and Addison's disease. The destruction of the gland by radiation is a rare cause of hypoparathyroidism. Occasionally, the parathyroids are absent at birth causing low calcium levels and possible convulsions in the newborn. Symptoms in the advanced and continuous stages of hypoparathyroidism include splitting of the nails, inadequate tooth development and mental retardation in children, and seizures.
Abnormal low levels of calcium result in irritability of nerves, causing numbness and tingling of the hands and feet, with painful-cramp like muscle spasms known as tetany. Laryngeal spasms may also occur causing respiratory obstruction.

Diagnosis

Diagnostic measures begin with the individual's own observation of symptoms. A thorough medical history and physical examination by a physician is always required for an accurate diagnosis. The general practitioner may refer the individual to an endocrinologist, a medical specialist who studies the function of the parathyroid glands as well as other hormone producing glands. Laboratory studies include blood and urine tests to help determine phosphate and calcium levels. X rays are useful to determine any abnormalities in bone density associated with abnormal calcium levels. These autoimmune disorders may accompany hypoparathyroidism, but are not an actual cause of it.

Treatment

In the event of severe muscle spasms, hospitalization may be warranted for calcium injections. Raising carbon-dioxide levels in the blood, which can decrease muscle spasms, may be achieved in immediate situations by placing a paper bag over the mouth and blowing into it to "reuse" each breath. It is critical to obtain timely periodic laboratory tests to check calcium levels. A high calcium, low-phosphorous diet may be of significance and is directed by the physician or dietitian.

Prognosis

Presently hypoparathyroidism is considered incurable. The disorder requires lifelong replacement therapy to control symptoms. Medical research however, continues to search for a cure.

Prevention

There are no specific preventive measures for hypoparathyroidism. However, careful surgical techniques are critical to reduce the risk of damage to the gland during surgery.

Resources

Organizations

American Medical Association. 515 N. State St., Chicago, IL 60612. (312) 464-5000. http://www.ama-assn.org.

Key terms

Addison's disease — A disease caused by partial or total failure of adrenocortical (relating to, or derived from the adrenal gland) function, which is characterized by a bronze-like pigmentation of the skin and mucous membranes, anemia, weakness, and low blood pressure.
Autoimmunity — A condition by which the body's defense mechanism attacks itself.
Calcitonin — A hormone produced by the thyroid gland in human beings that lowers plasma calcium and phosphate levels without increasing calcium accumulation.
Hashimoto's thyroiditis — The self destruction of the thyroid cells from an autoimmune disorder.
Hormones — A substance produced by one tissue and conveyed by the bloodstream to another to affect physiological activity, such as growth or metabolism.
Pernicious anemia — A severe anemia most often affecting older adults, caused by failure of the stomach to absorb vitamin B12 and characterized by abnormally large red blood cells, gastrointestinal disturbances, and lesions of the spinal cord.

hypoparathyroidism

 [hi″po-par″ah-thi´roi-dizm]
the condition produced by greatly reduced function of the parathyroid glands or by the removal of these bodies as a treatment for hyperparathyroidism. The lack of parathyroid hormone leads to a fall in serum calcium level, which may result in increased neuromuscular excitability and, ultimately, in tetany. There is also a rise in the plasma phosphate level, which results in a decrease in bone resorption and an increased density of bone. There also may be dermatologic, ophthalmologic (cataracts), psychiatric, and dental symptoms.

Treatment consists of raising the lowered calcium content of the blood. There are various forms in which calcium can be administered, and calcium injections will bring immediate improvement. However, if there is complete absence of parathyroid function the patient will have to continue to take oral preparations of calcium indefinitely.

hy·po·par·a·thy·roid·ism

(hī'pō-par'ă-thī'royd-izm), [MIM*241400]
A condition due to diminution or absence of the secretion of the parathyroid hormones, with low serum calcium and tetany, and sometimes with increased bone density.
See also: pseudohypoparathyroidism.

hypoparathyroidism

/hy·po·para·thy·roid·ism/ (-par″ah-thi´roid-izm) greatly reduced function of parathyroid glands, with hypocalcemia that may lead to tetany, hyperphosphatemia with decreased bone resorption, and other symptoms.

hypoparathyroidism

[-per′əthī′roidiz′əm]
Etymology: Gk, hypo + para, beside, thyreos, shield, eidos, form
a condition of insufficient secretion of the parathyroid glands. It can be caused by primary parathyroid dysfunction or by elevated serum calcium level.

hypoparathyroidism

Endocrinology A condition characterized by ↓ PTH and serum Ca2+ Etiology Congenital absence of the parathyroid glands, accidental excision or injury of parathyroid glands during thyroidectomy or other neck surgery; massive regional RT, magnesium deficiency Risk factors Recent thyroid or neck surgery, family Hx of parathyroid disorder, or autoimmune disease–eg, Addison's disease Clinical Tetany. See PTH.

hy·po·par·a·thy·roid·ism

(hī'pō-par'ă-thī'royd-izm)
A condition due to diminution or absence of the secretion of the parathyroid hormones, with low serum calcium, tetany, and sometimes increased bone density.
See also: pseudohypoparathyroidism

hypoparathyroidism

Reduced production of parathyroid gland hormone. This is rare except when two or more of the four glands have been accidentally removed in the course of a THYROIDECTOMY operation. There is a reduction in the level of calcium in the blood causing spontaneous production of nerve impulses and TETANY.

hypoparathyroidism

condition caused by reduced parathyroid hormone secretion

hy·po·par·a·thy·roid·ism

(hī'pō-par'ă-thī'royd-izm) [MIM*241400]
Condition due to diminution or absence of secretion of parathyroid hormones, with low serum calcium and tetany, and sometimes with increased bone density.

hypoparathyroidism (hī´pōper´ə-thī´roidizəm),

n a decrease in parathyroid function, usually the result of surgical removal. Symptoms include tetany, irritability, and muscle weakness. The serum calcium is low, the blood phosphorus elevated, the blood magnesium reduced, and the alkaline phosphatase normal.

hypoparathyroidism

the condition produced by greatly reduced function of the parathyroid glands or by the removal of these bodies. The lack of parathyroid hormone leads to a fall in serum calcium level, which may result in increased neuromuscular excitability and, ultimately, in tetany. There is also a rise in the plasma phosphate level, which results in a decrease in bone resorption and an increased density of bone.

iatrogenic hypoparathyroidism
usually due to accidental removal of the glands during thyroidectomy.
idiopathic hypoparathyroidism
recorded in dogs due usually to an immune-mediated diffuse lymphocytic parathyroiditis.
References in periodicals archive ?
Natpara (parathyroid hormone) for injection is indicated as an adjunct to calcium and vitamin D to control hypocalcemia in patients with hypoparathyroidism.
People with hypoparathyroidism have limited treatment options and face challenging symptoms that can severely impact their quality of life.
NATPARA was not studied in people with hypoparathyroidism caused by
Hypoparathyroidism occurs when the body secretes abnormally low levels of parathyroid hormone, which helps regulate calcium and phosphorus levels in the body.
The FDA's approval of NATPARA provides a new treatment option for patients with hypoparathyroidism C a devastating rare disease with significant unmet need.
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) about idiopathic hypoparathyroidism, the replacement of calcium and vitamin was then prescribed.
It demonstrates how a patient with a low postoperative intact PTH value of 5 pg/ml would be unlikely to develop significant transient hypoparathyroidism given a 6-hour serum calcium measurement of 8.
Although hypocalcemia has been reported in less than 1% overall of treated patients, severe cases have occurred in patients with malignancy, hypoparathyroidism, and unrecognized vitamin D deficiency.
Serum samples obtained from 72 healthy controls and 216 patients [primary hyperparathyroidism (n = 18), idiopathic hypoparathyroidism (n = 4), Paget disease of the bone (n = 9), metastatic bone disease (n = 8), uremic patients on hemodialysis (n = 177)] were measured in the Bio-PTH assay to determine values for healthy controls and the changes produced by various metabolic bone diseases.
Only one patient developed permanent hypoparathyroidism, and that case "followed a previous failed [thyroid] exploration at another institution," they said.
Chronic parathyroiditis may occur in patients with hypoparathyroidism, as well as in those with primary chief-cell hyperplasia.