Hypoparathyroidism, Pseudohypoparathyroidism, and Pseudo-Pseudohypoparathyroidism

Hypoparathyroidism, pseudohypoparathyroidism, and pseudo-pseudohypoparathyroidism are a triad of progressively named and related disorders of interest to both the internist and the ophthalmologist.

Hypoparathyroidism  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.¹ Idiopathic hypoparathyroidism, characterized pathologically by the absence of parathyroid tissue or its replacement by fat, is much less common; Steinberg and Waldron,² reporting 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 60.²⁸In 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