Hyperthyroidism is one of the most common endocrine conditions affecting cats, in particular, older cats over the age of 10. Some veterinarians estimate that about 2% of cats over 10 will develop hyperthyroidism, and, due to factors that may include environmental exposures, that number is on the rise. Untreated, hyperthyroidism in cats can lead to heart failure or kidney failure and can be fatal.
What every cat owner needs to know is:
- What is hyperthyroidism and how do cats get it?
- How common is it?
- Is it dangerous?
- What are the symptoms of hyperthyroidism?
- How is it diagnosed?
- What treatment options are there, and what is involved with those options?
- Are there any effective alternative approaches?

