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This parathyroid glands are the endocrine structures responsible for secreting parathyroid hormone (PTH) that play a major role in maintaining calcium physiology either directly via the enhancement of osteoclastic bone activity or indirectly by facilitating the production of the active form of vitamin D3 which exerts its effect by increasing gastrointestinal calcium absorption. Decreased secretion of PTH results in hypoparathyroidism.
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The most common cause of hypoparathyroidism is parathyroidectomy performed for the treatment of hypercalcemia caused by hyperparathyroidism. Similarly, another major cause is inadvertent resection of these glands during thyroidectomy. Other causes include infiltrating diseases such as amyloidosis and malignancy, or electrolyte abnormalities such as hypomagnesemia or hyperphosphatemia seen in chronic kidney disease.
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CLINICAL MANIFESTATIONS
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Essentially, the observed effects of hypoparathyroidism are directly related to the resulting hypocalcemia caused by decreased PTH. The symptoms observed depends on the rapidity at which hypocalcemia develops. Below are some of the symptoms associated with hypocalcemia:
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Neurologic—Lethargy, neuronal irritability, depression and paresthesias
Ocular—Cataracts
Cardiac—Hypotension, CHF, prolonged QT
Neuromuscular—Positive Chvostek sign (facial contracture elicited by tapping facial nerve) or positive Trousseau sign (fingers and wrist contracture elicited by inflation of blood pressure cuff above patient’s systolic blood pressure for 3 minutes or more)
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Treat underlying etiology—For example, correct any electrolyte abnormalities such as hypomagnesemia or hyperphosphatemia. Likewise, vitamin D supplementation to patients who have vitamin D deficiency may help resolve the problem.
Intravenous and oral supplementation—Depending on the severity of hypocalcemia, patients may benefit from immediate IV administration of calcium gluconate. On other patients, oral supplementation of calcium and vitamin will be sufficient to correct hypocalcemia.
Miscellaneous treatment—Avoidance of furosemide and usage of thiazide diuretics for select patients may help improve hypocalcemia.