Hypoparathyroidism, Pseudohypoparathyroidism, and Pseudo-Pseudohypoparathyroidism

Abstract

Hypoparathyroidism, pseudohypoparathyroidism, and pseudo-pseudohypoparathyroidism are a triad of progressively named and related disorders of interest to both the internist and the ophthalmologist. <h3>Hypoparathyroidism</h3> Hypoparathyroidism is most commonly of the secondary variety, following inadvertent removal or injury of the parathyroid glands during the course of thyroidectomy. Postoperative hypoparathyroidism occurs in approximately 1% of patients with thyrotoxicosis who undergo thyroid surgery.¹Idiopathic hypoparathyroidism, characterized pathologically by the absence of parathyroid tissue or its replacement by fat, is much less common; Steinberg and Waldron,²reporting a case of their own, could find, in reviewing the literature, only 52 other cases. Idiopathic hypoparathyroidism affects both sexes equally; the average age at onset is 17, but the disease may occur as late as age 60.²⁸ In hypoparathyroidism of either the idiopathic or the postoperative type the decreased secretion or the absence of the parathyroid hormone results in a lowered serum calcium, an