Hyperthyroid Symptoms / Signs | Feline | Spokane, WA
The Cat's Meow Feline Veterinary Clinic and Hyperthyroid Treatment Center Sitting black cat Top view photo of a cat
Different breeds of cats


a common endocrine disease

Symptom and signs of hyperthyroidism

Hyperthyroidism is the most common endocrine disease in cats. The cats are usually greater than 8 years of age with the average age of onset at 13 years.


Affected cats will often lose weight despite a good appetite and may have an increase in water intake and output.  Affected cats can also show signs of anxiety including increased vocalization, restlessness and aggression.  Many cats exhibit chronic vomiting and/or diarrhea.

Upon examination most affected cats will have lost weight and can often be thin or even emaciated. Heart rates are often elevated and can peak greater than 250 beats/minute (normal <180).  Affected cats may also have hypertension (high blood pressure). If left untreated they will die, often of heart failure.

Common clinical signs

The most common clinical signs are listed but it is important to know that your cat may exhibit all or none of these clinical signs. Laboratory tests are required to diagnose this disease:


• Weight loss despite a good appetite  

• Increased appetite

• Increased thirst  

• Increased urination (more frequent litter pan cleanings)

• Increased activity (or apathy)

• Increased vocalization

• Vomiting and/or Diarrhea

• Increased aggression

The Cat's Meow Feline Veterinary Clinic and Hyperthyroid Treatment Center

1017 South Perry Street

Spokane, WA 99202


Fax- 509-535-6377


Mon-Fri 8:00-5:30

(7:30 drop off)

Sat  9:00-12:00

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