Transient neonatal hypocalcemia, hypomagnesemia, and high serum parathyroid hormone with maternal hyperparathyroidism.

Findings in a case of neonatal tetany in a child whose mother had elevated blood parathyroid hormone levels because of a parathyroid adenoma are given. The child was found to have hypocalcemia, hypomagnesemia, and hyperphosphatemia. Parathyroid hormone in the infant was found to be elevated. It has been postulated that the pathophysiologic mechanism of the hypocalcemia in this syndrome is transient hypoparathyroidism. The present case suggests a different mechanism: hypomagnesemia and end-organ refractoriness to parathyroid hormone, a state analogous to pseudohypoparathyroidism.