Acute hypocalcemia associated with infarction of parathyroid gland adenomas in two dogs.

Two dogs were examined because of anorexia, lethargy, muscle tremors, weakness, and seizures that were associated with an acute onset of hypocalcemia. Both dogs had histories of chronic hypercalcemia. Examination of the parathyroid glands revealed infarction of focal parathyroid adenomas, with atrophy of the remaining parathyroid glands. It was concluded that the acute onset of hypocalcemia was caused by infarction of functional parathyroid adenomas that were previously responsible for the cause of persistent hypercalcemia. Infarction of a parathyroid adenoma should be included in a list of differential diagnoses of acute hypocalcemia in the dog, especially if hypercalcemia has been diagnosed previously.