Bone Abstracts

Hypoparathyroidism is a disorder characterized by hypocalcemia, low or absent parathyroid hormone (PTH), and abnormal bone remodeling. The diagnosis is made in the setting of hypocalcemia with markedly reduced or absent PTH levels. Postoperative hypoparathyroidism is the most common etiology. Other causes of hypoparathyroidism include autoimmune disease and rarely, congenital syndromes of parathyroid dysgenesis such as DiGeorge syndrome. Standard treatment of hypoparathyroidism consists of oral calcium and vitamin D supplementation at various doses with the goal of ameliorating symptoms of hypocalcemia, maintaining normal serum calcium, and reducing urinary calcium excretion. Patients are typically not easily controlled with standard therapy. Hypoparathyroidism is the only classic endocrine deficiency disease for which the missing hormone is not yet an approved treatment. Subcutaneous recombinant human (rh) PTH(1–34) and rhPTH(1–84) have been studied. In hypoparathyroidism, both rhPTH(1–34) and rhPTH(1–84) lower calcium and vitamin D requirements while maintaining serum calcium levels. Other potential benefits of PTH therapy include an improvement in skeletal dynamics toward more normal levels and improvement in quality of life.