How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Dr. Smith Your Own Question
Dr. Smith
Dr. Smith, Veterinarian
Category: Cat
Satisfied Customers: 1368
Experience:  Veterinarian in Small Animal Practice for 12 years
Type Your Cat Question Here...
Dr. Smith is online now
A new question is answered every 9 seconds

Seizure and Hyperthyroid

This answer was rated:

-------------------------------------------------------------------------------- 14 yo cat had a seizure on Tue and Wed mornings. Vet visit Tue show new 2+3+ murmur (since visit 1 year ago), wt loss 13.5 to 10.2. Full senior blood profile came back today (Fri)....hyperthyroid level at 8.2. No seizures since Wed. Question...could the seizures be secondary to organ involvment (cardiac? or other) from the hyperthyroidism? My vet did not think she had heard or seen seizures with hyperthyroid. Trying to get a grasp on if we have two seperate problems or one. I know murmurs and arrythmias can cause clots, but do they usually occur in this scenario? Thanks!!!!!

Hi David,

In a 14 year old cat, hyperthyroidism can be very common. It very commonly does have quite severe side effects on the heart, and most hyperthyroid cats have some degree of cardiomyopathy. Most cases of cardiomyopathy in cats are of the Hypertrophic type which can preclude them to throwing clots. Thromboembolic events or clots can cause various problems in the body ranging from weakness to paralyis to obstruction of cerebral vasculature which could manifest as a stroke or in rare instances possibly induce a seizure.

So to answer your question, hyperthyroidism does not directly cause seizures in the truest sense. Instead, cats with cardiomyopathy secondary to hyperthyroidism can often develop hypertension ( high blood pressure) which can result in vascular accidents or hypoxia( oxygen loss at the tissue level) which may cause seizures.

I would strongly recommend thoracic radiographs, an EKG,and several periodic blood pressure measurements over the course of the day. Your pet should commence treatment of the hyperthyroidism with Methemizole as directed by your veterinarian and I would also consider the usage of Enacard and Baby Aspirin therapy to treat the underlying cardiomyopathy.

Your vet will need to do serial bloodwork testing over the course of Methimazol (Tapazole) treatment in order to insure that the proper maintenance dose is established and that your cat's thyroid levels are back to a normal physiologic level.

Your pet's hyperthyroidism may be due to an actual tumor of one of the thyroid glands ,so surgical removal of the affected gland or radiation therapy may be called for in place of Methamizole therapy.

Please remember to press "ACCEPT" upon reading this answer. Bonuses area accepted with gratitude. I appreciate your trust in my professional knowledge and clinical experience. Please remember to leave feedback, as feedback affects my ratings and earnings.

Best Wishes to You and Your Pet!
Dr. Jodi L. Smith

Dr. Smith, Veterinarian
Category: Cat
Satisfied Customers: 1368
Experience: Veterinarian in Small Animal Practice for 12 years
Dr. Smith and 3 other Cat Specialists are ready to help you
Customer: replied 9 years ago.
Thanks for your insight. My primary vet has me referred to a specialist group here in Atlanta, but the Emergency dept has been the only dept. open since the holiday, so it is hard to wait till Monday to get more insight and I could not find anything on the Internet about seizure activity with hyperthyroidism. I am a CRNA and it is hard to not find/have answers to health problems when you know how to look and understand information...when you can find it! My plan is to go directly to the Radioactive Iodine injection to treat the hyperthyroid and guess I will have to see how the internist wants to work up the cardiac/seizure problem in it's relation or non-relation to that. If you would like, I will let you know the process and outcome next week of the workup.


JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • The response from the Expert literally saved my cat's life. Thank you from the bottom of my heart -- I will recommend all of my friends to you!!! Lucia Rincon, Georgia
< Previous | Next >
  • The response from the Expert literally saved my cat's life. Thank you from the bottom of my heart -- I will recommend all of my friends to you!!! Lucia Rincon, Georgia
  • I will use your service again. I was very pleased with the response and the fact that you have a low cost option so that those of us on fixed income can have questions answered. I will also recommend you to others. Karen Jackson Heights, NY
  • You helped us to come to what we believe is a better next step in Jack's treatment, and hopefully have saved us $800!! Thanks again! Jack's Mom Tuscon, AZ
  • The vet said that the information and my following it will be what made the difference. Thanks again for being so very helpful. Tracy Grayson, LA
  • My oldest male cat had a seizure this evening. This site was the first place I could think of to go after the seizure had passed. Dr. Lucy was fantastic and she was spot on! Debbie USA
  • I must tell you I found this site by accident and was amazed when I asked a question of the Veteranians online. I wish I could have found it sooner it could have made such a difference in the outcome of my pet's surgery. However, I am passing along the information to my sister-in-law (a cat-rescue person who is also a nurse), and perhaps it will help someone else who may experience the same problem. The doctor who answered my question was amazing, and while it didn't come it time to change the outcome of my situation, it is reassuring to know the caliber of Vets/Doctors that you have at JustAnswer. Thank you for being there. Alice H. Jacksonville, Fl.
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK

Meet The Experts:

  • Terri


    Feline Healthcare Expert

    Satisfied Customers:

    Expert in feline health and behavior. 20 years experience with cats.
< Last | Next >
  • Terri's Avatar


    Feline Healthcare Expert

    Satisfied Customers:

    Expert in feline health and behavior. 20 years experience with cats.
  • Dr. Gary's Avatar

    Dr. Gary

    Cat Veterinarian

    Satisfied Customers:

    DVM, Emergency Veterinarian; BS (Physiology) Michigan State Univ
  • Cher's Avatar


    Feline Specialist

    Satisfied Customers:

    Feline Healthcare & Behavior Specialist 40+ years Experience
  • Lori's Avatar


    Feline Healthcare

    Satisfied Customers:

    16 yrs health care mgmt & issues relating to cats, reproductive issues and multicat environments
  • Micki's Avatar


    Expert in cat behavior and health

    Satisfied Customers:

    Expert in cat medical and behavior issues.
  • Candy R.'s Avatar

    Candy R.

    Veterinary Technician

    Satisfied Customers:

    Practicing Veterinary Technician for 26 years.Former Veterinary Practice Owner, Technician Trainer
  • Theresa's Avatar


    A Voice for your Pet

    Satisfied Customers:

    19+ years in animal medicine as a veterinary technician