On the etiology of "primary" hyperparathyroidism.

A study of 92 patients operated on for primary hyperparathyroidism revealed that the condition was secondary to renal disease, thyrotoxicosis or malignancy in 35. Review of the literature revealed no reports of experimental studies on the relationship between hyperparathyroidism and thyrotoxicosis or malignancy. In renal disease, however, the author's own investigations show that the traditional concept of hypocalcemia as the most important factor in the development of parathyroid hyperfunction should be rejected. The parathyroid glands probably can be stimulated by various factors in "primary" hyperparathyroidism. Recent studies on the etiology of primary hyperparathyroidism are discussed and it is concluded that the term "primary" should be avoided as the disease is so often secondary.