A WELL-DOCUMENTED case of renal disease in an adult with marked secondary hyperparathyroidism and metastatic calcinosis is of sufficient rarity and interest to warrant publication.
A distinction between primary and secondary hyperparathyroidism is not always simple, for primary hyperparathyroidism in late phases of the disease may effect the renal function to such an extent as to reverse its originally characteristic calcium-phosphorus balance. In primary hyperparathyroidism one expects low serum inorganic phosphorus and high serum calcium and phosphatase levels with increased output of calcium in the urine, whereas in hyperparathyroidism secondary to chronic renal insufficiency with nitrogen retention phosphate is retained by the kidney, the serum inorganic phosphorus level is elevated, and the calcium level is low. If in the course of longstanding primary hyperparathyroidism renal calcinosis or lithiasis becomes sufficiently severe to interfere with renal function, the originally low phosphorus blood level may eventually rise, the calcium level fall, and the