[The diagnosis of hyperparathyroidism and hypoparathyroidism]

Some recent pathophysiologic, diagnostic and therapeutic aspects of hyper- and hypoparathyroidism are reviewed. Three clinical forms of hyperparathyroidism can be distinguished: one with symptoms essentially affecting the skeleton, a second with renal symptoms and a third with scant and sometimes atypical symptoms. The most reliable laboratory criteria for diagnosis of hyperparathyroidism are serum levels of calcium and immunoreactive parathormone. Some authors believe that with a combination of these two parameters a diagnosis is possible in almost all cases. Other determinations such as serum phosphorus and 24-h urinary calcium, and most special tests, are less reliable. A new method for preoperative localization of adenoma, involving catheterization of the thyroid veins, should make future operative procedures easier. With regard to pseudohypoparathyroidism, recent work has contributed to a greater understanding of the pathophysiologic mechanism. On the basis of normal or elevated parathormone in these cases and in other investigations, Albright's hypothesis, which assumes resistance of the renal tubules to parathormone is considered to be proven. Hypoparathyroidism is usually fairly easy to treat with vitamin D or AT 10 and calcium supplements, provided that frequent and careful checks on serum calcium levels are made.