The typical signs for hyperthyroidism are many and varied. Rarely does a cat show all of the signs, but the most common clinical signs are:
- Weight loss, often despite an increase in appetite
- increased appetite, demanding food more often
- Vomiting and diarrhea
- Increased energy or irritability
- Drinking and urinating more
- Increased heart rate (difficult to assess for owners)
I adopted Herman when he was about 7 months old. He had been abandoned, and always acted like every meal was his last (i.e. a great appetite!). Herman's main clinical signs were lethargy and weakness. He seemed to age before my eyes. Once a robust "talky" kind of cat loaded with personality, he seemed to always be sleeping and just not have that "spark". These changes were subtle at first, and I had to keep reminding myself that he is getting up there in age (as much as I hate to admit it), but something just wasn't adding up.
Apathetic hyperthyroidism is described as a case in where the patient is lethargic, weak and in some cases, anorexic. These symptoms are rare, and are directly opposite from what is seen in "classic" hyperthyroid cases.
Thankfully, Herman's case has been caught early; his thyroid values are not sky high and the rest of his bloodwork looks OK for his age. Treatment will be started shortly, and is discussed in Part II of this article.
Hyperthyroidism In Cats