Hyperthyroidism signs I missed

Hi everyone. I am a little worried about Patti. She is an 11-year-old female and lately she has been acting very thirsty. Her water bowl is empty twice a day now, which is new for her.

Her urine is also becoming lighter in color. I have written up the full history, the vet visit notes, and what we have tried so far in my other thread Patti's cat: recent symptoms and vet notes. I just want to ask here if anyone else has seen these specific signs, especially the light urine, with hyperthyroidism. Is that a common clinical sign?

Oh no, that sounds stressful. I am out of the office most of the day so I rely on the forum a lot. Have you checked her weight recently? Hyperthyroid cats usually lose weight even if they are eating more. Patti is 11, so she is in that age range where it happens a lot.

JennyH is right about the weight loss. As a vet tech, I see hyperthyroidism a lot. The classic signs are weight loss, increased appetite, and sometimes vomiting or a rough coat. Polydipsia (increased thirst) is very common, but the urine color is not a primary diagnostic sign for thyroid issues. It is more often associated with kidney function. Since Patti is 11, we have to look at both. Did the vet check her kidney values in the blood work?

I am so anxious reading this! My Coco is 14 and has hip issues, but I see a lot of senior cats here having problems. I remember reading about Milo's hip arthritis and mobility and it made me worry about all the old cats. But swebb is right, kidneys are a big one. I have a thread about Kidney disease signs in senior cats if you want to compare notes on the urine stuff. Lighter urine can definitely be a kidney thing.

I appreciate the clinical input, swebb, but I would like to see some data. Is there a study or a consensus guideline that specifically lists "light urine" as a sign of hyperthyroidism? I am skeptical that it is a direct symptom of the thyroid itself rather than a secondary effect of the high water intake. If it is just dilution from drinking so much, that doesn't point to the thyroid specifically. It points to the behavior.

Khali is technically correct. The dilution is likely just because she is drinking so much. But the *reason* she is drinking so much is the question. In an 11-year-old cat, hyperthyroidism and kidney disease are the top two suspects. They often overlap. I would not wait. If you haven't already, ask the vet for a T4 test and a creatinine check. It is better to rule one out than to guess.

Thank you all. The light urine is just because she is drinking so much, I suppose. I will push for the T4 test. I saw Whiskers' arthritis and joint care earlier and it reminded me how many different things can go wrong at once in older cats. Patti is still eating well, but I am worried about the thirst.