Summary

Objective: Retrospective evaluation of diagnosis and outcome in 20 dogs with primary hyperparathyroidism. Material and methods: In 20 dogs primary hyperparathyroidism was diagnosed and 19 patients were treated via parathyroidectomy, 10 additionally with partial thyroidectomy. Medical records of the dogs were reviewed for signalment, clinical features, laboratory findings and results of histopathologic examination. In some cases postsurgical rehabilitation of calcium metabolism required substitution with calcium and vitamin D preparations. Results: Mean age of the dogs was 11.5 years. The most common clinical signs comprised polydipsia, polyuria, reduced activity, and stiff gait. Laboratory findings were moderate to extensive hypercalcaemia, low or low-normal serum phosphorus concentrations and normal or increased serum parathyroid hormone concentrations. None of the dogs had an elevated parathyroid hormone-related polypeptide level. Histological examination revealed 11 adenomas, six carcinomas and two glandular hyperplasias. Postsurgical management of calcium homeostasis was challenging in some cases. Conclusion:

Tumours of the parathyroid gland can be easily treated by parathyroidectomy and usually have a good prognosis. Clinical relevance: With careful interpretation of laboratory findings of a patient presenting with hypercalcaemia and ruling out other causes of hypercalcaemia diagnosis of primary hyperparathyroidism can be easily achieved and successfully treated byparathyroidectomy.