Newton’s Purrspective – Hyperthyroidism
Hyperthyroidism is a common disease in older cats ( > 10 years). Enlarged thyroid glands produce too much hormone (T3 and T4) causing a metabolic imbalance which leads to severe health issues if untreated. Cornell Feline Health Center – Hyperthyroidism in Cats
Symptoms often include:
- Increased appetite
- Weight loss
- Increased water consumption and urination
Thyroid hormones affect nearly all the organs so these secondary problems are common:
- Increased heart rate
- Enlargement of the heart (and heart disease)
- Increased blood pressure
- Kidney disease (due to the kidneys working overtime as the blood rapidly circulates)
Diagnosis involves feeling Kitty’s throat for enlargement of the thyroid glands and a blood test for thyroid hormone levels. (Please note these symptoms could also indicate diabetes or other problems. That is why the bloodwork is so important.)
The good news is that hyperthyroid disease responds well to current medications. Medications – easier said than done, right? Compounding pharmacies now make tastier pills and chewables. A gel that is applied to the inside of Kitty’s ear has been a lifesaver for cats that hate ALL oral medications (you know who you are).
The two alternative treatments are:
- Removal of the thyroid glands (which carries a surgical risk)
- Treatment with radioactive iodine to destroy the abnormal tissue
The latter is quite safe and effective, but may be out of range in most cat lovers’ budgets.
Now that you know the basics about hyperthyroidism symptoms and treatments you are probably wondering how cats get it in the first place. We know that the incidence of feline thyroid disease has increased in the last 30 years. This is likely a combination of awareness and of increased longevity in general. Remember this is a disease of older cats. But can a direct cause be determined? Is it genetic? Is it environmental?
Some researchers are looking at environmental toxins that may also be incorporated into cat foods. Research is just starting to be published. http://www.chicagonow.com/steve-dales-pet-world/2016/01/could-some-cat-food-be-causing-hyperthyroid-disease/ One study found chemicals known to potentially harm humans in certain fish based cat foods. However, to date there is no demonstrated link to feline hyperthyroidism. Additional research is clearly needed.
Environmental toxins are a concern for all of us. You may remember the classic “Silent Spring” which led to banning the poison DDT. A less familiar book “Our Stolen Future” describes how chemicals can mimic hormones in the body. When we discover what causes hyperthyroidism in cats we will also better understand thyroid issues in other species, including humans. Until then our best defense is a good offense.
All cats should have regular checkups. If Kitty has any of the symptoms listed above please see your vet as soon as possible. Catching and treating thyroid problems early can minimize the damage to other organs.