Key Features

Etiology

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  Iatrogenic (surgical): This is the most common cause of hypoparathyroidism. This may occur after surgery on the neck (thyroidectomy, parathyroidectomy, or neck dissection). It maybe transient with recovery within days to weeks, or it may be permanent. It usually occurs as a result of manipulation of blood supply to the parathyroid glands during surgery or injury to or removal of one or more parathyroid glands.

  
  
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  Patient who have undergone gastric bypass are more susceptible to severe postthyroidectomy hypocalcemia.

  
  
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  Hypoparathyroidism may also occur in the setting of “hungry bone syndrome” following surgery. In this case, bones readily take up calcium and phosphate. This is usually associated with severe preoperative hyperparathyroid bone disease.

  
  
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  Autoimmunity: This occurs secondary to immune-mediated destruction of parathyroid glands. This may be acquired or familial.

  
  
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  Hypoparathyroidism may occur due to abnormal development of the parathyroid glands. This is usually associated with DiGeorge′s syndrome, which is a congenital abnormality of the third and fourth branchial pouches and results in the absence of parathyroid glands and thymus.

  
  
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  Idiopathic hypoparathyroidism is more common in females and has been associated with anti–parathyroid hormone (PTH) antibodies.

  
  
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  Hypoparathyroidism may result from the destruction of parathyroid glands by irradiation or infiltrative diseases (such as metastatic cancer and granulomatous disease) or storage diseases (such as Wilson′s disease and hemochromatosis).