Hyperthyroidism is the most common hormonal disease of older cats. Understanding the trade-offs between medical, surgical, and radioiodine treatment guides optimal welfare decisions.
Hyperthyroidism causes significant suffering through its systemic effects — weight loss, cardiovascular strain, anxiety from hyperactivity, and gastrointestinal distress. All three treatments are effective, but they differ substantially in their welfare implications. Medical management requires twice-daily tablets for life, creating chronic pill-related stress for cat and owner. Radioiodine provides a single curative treatment with only a brief isolation period. For cats where radioiodine is available and affordable, the lifetime welfare benefit of cure over management is substantial.