Hypercalcemia secondary to chronic renal failure in the dog: a report of four cases.

Hypercalcemia occurred in 4 dogs with renal failure. Primary causes of hypercalcemia previously described in the dog (primary hyperparathyroidism, pseudohyperparathyroidism, vitamin D toxicosis) were not identified. Increased concentrations of circulating immunoreactive parathormone were found in 2 dogs, and thyroparathyroidectomy of 1 dog resulted in decreased serum concentrations of that hormone as well as of calcium. The latter observations indicated that hypercalcemia was related to increased parathormone activity, but the possibility of other homeostatic imbalances was not excluded. It was concluded that renal failure should be considered as a primary cause of hypercalcemia, along with other causes previously identified.