Go to a clinic immediately if
- The cat has breathing difficulty, collapse, profound weakness, sudden vision trouble or stops eating
- Sudden blindness, disorientation or seizure may be a complication of dangerously high blood pressure
Possible signs
- Weight loss despite a good or increased appetite, hyperactivity, increased thirst, vomiting, diarrhea or an unkempt coat
- A racing heartbeat, louder vocalisation, nighttime restlessness and heat intolerance may accompany other signs
What it is
In hyperthyroidism, enlarged thyroid tissue produces excess hormone and accelerates metabolism. Most cases are caused by benign change and a small minority by cancer. It mainly affects middle-aged and older cats and can cause hypertension, thickening of the heart muscle and heart failure; treatment may also reveal kidney disease that was previously masked.
What to expect at the veterinarian
The veterinarian will examine the neck, heart rate, weight and blood pressure and measure thyroid hormones. A normal or borderline initial T4 does not always exclude disease, so repeat or additional testing may be needed. Options include daily medicine, radioactive iodine, surgery or a strictly iodine-restricted diet, each with different benefits, risks and monitoring needs.
Sources
- Guideline or consensus statement. Hyperthyroidism in Cats