Primary hyperparathyroidism in a 4-month-old German Shepherd mixed breed dog

A 4-month-old female-intact German Shepherd mixed breed dog was evaluated for polyuria, polydipsia, oral discomfort, tachypnea, and pyrexia. Blood testing documented total and ionized hypercalcemia with an increased parathyroid hormone concentration. Computed tomography identified bone abnormalities of the mandibule and mild, diffuse pulmonary changes. Ultrasonography of the neck documented one mildly enlarged parathyroid gland that was surgically removed. Histopathology indicated diffuse chief cell hyperplasia. The ionized calcium concentration normalized within 7 days postoperatively.