What are the symptoms of feline hyperthyroidism (Hyperthyroidism in cats)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 23, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Research

Hyperthyroidism in cats is characterized by symptoms such as weight loss despite increased appetite, increased thirst and urination, hyperactivity, restlessness, vomiting, diarrhea, and an unkempt coat, as well as a rapid heart rate, heart murmurs, and high blood pressure, as reported in a study published in the Journal of the American Veterinary Medical Association 1.

Key Symptoms

  • Weight loss despite increased appetite
  • Increased thirst and urination
  • Hyperactivity and restlessness
  • Vomiting and diarrhea
  • Unkempt coat
  • Rapid heart rate and heart murmurs
  • High blood pressure These symptoms occur due to the excessive production of thyroid hormones, which accelerate the body's metabolic processes.

Affected Population

Older cats, typically over 8 years old, are most commonly affected by hyperthyroidism.

Importance of Veterinary Attention

If these signs are noticed, especially weight loss with increased appetite in an older cat, veterinary attention is needed promptly to diagnose and treat the condition.

Diagnosis and Treatment

Diagnosis typically involves blood tests measuring thyroid hormone levels, and treatment options include medication (methimazole), radioactive iodine therapy, surgery, or prescription diets.

Potential Complications

Without treatment, hyperthyroidism can lead to serious complications, including heart disease, kidney damage, and severe weight loss. It is essential to prioritize the health and well-being of cats with hyperthyroidism to prevent these complications and ensure a good quality of life.

References

Research

Hyperthyroidism in the cat: ten cases.

Journal of the American Veterinary Medical Association, 1980

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.