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My cat is meowing loudly, losing weight, and acting aggressive. Why?

Updated on September 23rd, 2025

Pet's info: Cat | Russian Blue | Female | spayed | 13 years and 11 months old

My cat has been acting strange as of late. She will go to a room and meow/howl. She will do this at all hours without reason.She is also responsive to both sight and sound. She has also been sitting by the litter box from time to time. Weight loss has also been a concern. She has been eating and drinking and active with play. There is also slight hostility towards her sister.

1 Answer

Most Helpful Answer

Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

Veterinarian

Published on September 26th, 2019

These sudden changes in temperament and the weight loss are commonly due to an endocrine problem called hyperthyroidism.
The thyroid starts working more than normal increasing the metabolism (that is the cause of the weight loss) and causing behavioural changes similar to what you described.
A clinical examination at your local veterinarian is essential to confirm this clinical suspicion and treat appropriately. A blood test and urine analysis are needed.
Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

1Pet Parents found this answer helpful

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