Hyperthyroidism is a hormonal disease commonly found in older cats. The condition occurs when too much of the hormone thyroxine is produced, causing your cat's metabolism to speed up, which can impact on their physical and mental well-being. There's not usually an identifiable cause when a cat develops hyperthyroidism, but it can occur as a result of the thyroid nodules working out of sync from your cat's pituitary gland, which is the gland responsible for hormone production and regulation. Here's an overview of the symptoms, diagnosis and treatment options for hyperthyroidism in cats:
Symptoms of hyperthyroidism in cats include the following:
- Weight loss
- Gastrointestinal upset
- Increased thirst with increased urination
- Increased hunger
- Rapid breathing
- Lump on the neck, which is their enlarged thyroid gland
- Rapid heart rate
- Anxiety, which may present as pacing, loss of interest in play, excessive meowing or excessive grooming
Your vet will diagnose hyperthyroidism by taking details of your cat's symptoms and organising a few tests. The symptoms of hyperthyroidism are similar to those observed in cats with liver disease and kidney failure, so your vet will rule out these conditions with routine blood tests. The vet will also test your cat's blood serum for high levels of the hormone tetraiodothyronine, which indicates hyperthyroidism. Diagnostic imaging may also be used to understand the impact of hyperthyroidism on your cat's lungs and heart, particularly if they have experienced a rapid heart rate or rapid breathing.
Once your vet has made a diagnosis, they will formulate a treatment plan with you. First-line treatment for hyperthyroidism tends to be prescription medication to regulate the thyroid gland, and your cat will need to take this medication for the rest of their life. Your vet will regularly monitor the hormone concentration in your cat's blood serum to ensure they are receiving the optimum dose of medication. This medication is effective for most cats, but when drug treatment fails your cat may need to have the affected thyroid gland removed. As with any surgery, this procedure comes with risks, and a possible risk of removing the affected thyroid gland is that the remaining thyroid gland may become overactive. Your vet will be happy to discuss the pros and cons of surgery with you.
Untreated hyperthyroidism can lead to malnutrition, due to the speed of your cat's metabolism, and heart failure. So, if your cat is displaying any of the symptoms associated with hyperthyroidism, schedule an appointment with your vet as soon as possible.