Too much thyroid hormone can rev up your feline

Egypt, an 11-year-old Siamese-cross cat, was not a happy camper. She was agitated and irritable.

Her owners, Theresa Greiner and John Madden of Fiddler Ridge Nursery in Potlatch, Idaho, thought it was depression at first.

She had just lost her companion for life, a 22-year-old cat named Walter, who had raised her from a kitten. It was after Walter’s death that they started noticing the symptoms.

Egypt was cranky and would lash out at the dog or people if they went by her. But she had a good appetite and in fact started eating more.

And she seemed more active than an old cat should, racing around and playing in the garden like she had the Energizer Bunny in her.

“At first we thought, gee, that’s nice. She is having a good day,” said Greiner.

But then Egypt started getting a strange pattern of hair loss. She was pulling out her hair and created a reverse Mohawk on her back.

It was the concern about the hair loss that prompted Greiner and Madden to take her to her veterinarian, who made the diagnosis of hyperthyroidism.

The thyroid gland is a bilobed gland that sits at the base of the neck and produces thyroid hormone. Like a thermostat for the body, it’s responsible for regulating the metabolic rate.

If the thyroid gland doesn’t produce enough thyroid hormone (hypothyroidism), the metabolism slows. If the thyroid gland produces too much thyroid hormone (hyperthyroidism), the metabolism becomes revved like a race car.

Interestingly, dogs are more likely to experience hypothyroidism, while cats are more likely to get hyperthyroidism. The causes for the development of hyperthyroidism in cats are unknown.

Because thyroid hormone functions in so many organ systems, the signs of this disease can be variable. In addition, the onset of the disease is often insidious, with slow subtle changes that the owner often attributes to other causes.

“The most consistent sign of hyperthyroidism is weight loss,” says Arnold Plotnick, DVM, ACVIM, ABVP, owner of Manhattan Cat Specialists in New York City. “The next most consistent sign is exceptionally good appetite.

“After those signs, you may or may not see any or all of the following signs: excessive thirst, excessive urination, vomiting, diarrhea, panting, excessive shedding, and restlessness or hyperactivity.

“I’ve seen and treated hundreds of hyperthyroid cats and have seen all manifestations. But by far, the most consistent signs are weight loss despite a ravenous appetite.”

There are three treatments available for hyperthyroidism, each with its own set of considerations: surgery to remove the overactive glands, lifelong medication to reduce thyroid hormone levels, and treatment with radioactive iodine. The decision of which treatment option to use needs to be made in concert with your veterinarian, following the evaluation of numerous factors.

Greiner and Madden opted to take the medication route with Egypt, and this has worked well for them.

While we used to just assume that older cats came down in weight as they aged, more attention is being paid to this as a health concern in older cats.

“Weight loss is not only a sign of hyperthyroidism, said Plotnick. “Weight loss is also seen in chronic renal failure and often in diabetes, so I’d consider weight loss a real good reason to bring an older cat in for a checkup.

“Excessively good appetite is also a good reason to see the vet,” continued Plotnick. “Because cats tend to stop eating when they feel sick, most cat owners will call the vet if their cat stops eating.

“However, we often erroneously assume that a hearty appetite means that the cat is fine.

” ‘Whoa, look at him eat, he must feel great!’ right?

“Not necessarily. Hyperthyroidism and diabetes both are often accompanied by signs of excessive appetite. A normal appetite may indeed be, well… normal.”

Many diseases in older cats cause slow, subtle changes, but these serious diseases, like renal failure, diabetes and hyperthyroidism, can be best managed and your pet’s life extended and welfare improved, if caught early.

By paying attention to things like weight loss, activity levels and appetite and keeping your veterinarian in the loop, you can help your older kitty age gracefully and maybe add years — good years — to their lives.