Hyperthyroidism in Cats
What is Hyperthyroidism?
If your cat is always hungry and ravenous, begging for food yet seems to be losing weight; your cat may have hyperthyroidism. Hyperthyroidism occurs when a cat’s thyroid gland produces excess amounts of thyroid hormone. This is usually caused by a benign (non-cancerous) tumor on the thyroid gland. Some tumors, although it is a very small percentage, can be malignant (cancerous).
Middle-aged and older cats are most affected by hyperthyroidism. Thyroid hormones play an important role in controlling the body’s metabolism, so most cats with this disease tend to burn up energy too rapidly and lose weight despite eating more. Other symptoms associated with the disease can be increased drinking and urination, high blood pressure, and heart disease.
What are typical signs of Hyperthyroidism?
The typical signs include the following:
- Weight loss, despite increased appetite
- Restlessness or hyperactivity
- Diarrhea and/or vomiting
- Increased thirst and urination
- Irritability or nervousness
- Unkempt hair coat
- Lethargy or weakness
How is Hyperthyroidism diagnosed?
In some cats, the thyroid gland becomes noticeably enlarged, which may be felt by the veterinarian during an exam. After performing a thorough exam, your veterinarian will recommended a blood test to check for elevated thyroid hormone levels.
If the results come back high, your vet may need to run additional testing. This can include:
- Additional blood work
- Urinalysis
- Radiographs
- Electrocardiogram
- Ultrasound of heart
- Check of Blood Pressure
What are the treatment options for Hyperthyroidism?
There are 3 ways to treat hyperthyroidism: medication, surgery, or radiation therapy. If the medication route is chosen, cats will have to be on medication for the rest of their lives. This medication prevents the thyroid from producing too much hormone but is not a cure. Periodic blood testing is required to check that thyroid hormone levels remain within normal limits.
Surgical removal of the affected thyroid gland is another option. If the cat is healthy enough to undergo anesthesia and surgery, this option can offer a more permanent solution to the disease.
Radioactive iodine therapy is the last and most expensive option. This involves giving your cat injections that will destroy the diseased thyroid tissue without harming the thyroid gland itself. This treatment is not available at all clinics (including ours) due to the regulations of handling radioactive materials.
Is Hyperthyroidism preventable?
It is difficult to determine what measures to take to avoid it due to the fact that the exact cause of hyperthyroidism is unknown. Regular exams and bloodwork are recommended to help make an early diagnosis and initiate treatment.