Hyperthyroidism in Dogs: Rare but Welfare-Significant

Key Welfare Considerations

• Canine hyperthyroidism is rare — in contrast to cats, it typically indicates malignant thyroid adenocarcinoma.
• Clinical welfare signs include weight loss despite polyphagia, polyuria, polydipsia, and palpable neck mass.
• Cardiovascular welfare effects include tachycardia, hypertension, and hypertrophic cardiomyopathy.
• Thyroid carcinomas in dogs are often bilateral and invasive — welfare prognosis depends on staging.
• Surgical thyroidectomy is the primary welfare treatment for resectable thyroid tumours.
• Radioiodine (I-131) therapy provides welfare treatment for non-resectable or metastatic disease.
• External beam radiation therapy is an alternative welfare option for invasive thyroid tumours.
• Toceranib (Palladia) tyrosine kinase inhibitor shows welfare benefit in measurable thyroid carcinoma.
• Adjuvant chemotherapy with doxorubicin provides welfare benefit for metastatic thyroid carcinoma.
• Blood pressure management with amlodipine protects welfare organs from hypertensive damage.
• Post-surgical hypocalcaemia from parathyroid removal requires welfare monitoring and supplementation.
• Hypothyroidism following bilateral thyroidectomy requires lifelong thyroxine welfare supplementation.
• Median welfare survival with surgery for non-metastatic adenocarcinoma is 2-3 years.
• Regular welfare monitoring through chest radiography detects welfare-significant pulmonary metastasis.
• Quality of life welfare in dogs with managed thyroid carcinoma can be maintained for considerable periods.