Primary hypoparathyroidism in the dog.

Primary hypoparathyroidism was diagnosed in six dogs with profound hypocalcemia. Muscle tremors, tetany, generalized seizures, ataxia, and behavioral aberrations were the most common clinical signs. Lymphocytic parathyroiditis was found in four of five dogs that were biopsied. The serum concentration of immunoreactive parathyroid hormone was abnormally low in one dog in which it was measured. Treatment with vitamin D and calcium was successful in restoring and maintaining normal concentration of serum calcium in all six dogs. During treatment, large daily doses of vitamin D were required, dose response was unpredictable, serum calcium concentration fluctuated while treatment remained unchanged, and hypercalcemia occurred frequently.