I don't know what is the cause. She seems fine otherwise. It's not a UTI-she's not going every few seconds or every few minutes. Has she developed idiopathic cystisis? Is she dehydrated, constipated? Her last CBC/chem panel in May showed no signs of any issues other than dehydration. So, she's not idiopathic hypercalcemic or anything else.
By the way, we now have a cat with hypercalcemia-high levels of calcium in the body. It's our oldest male who has been on amitriptyline since October. That means the body is absorbing calcium instead of excreting it. High levels of calcium lead to crystals and blockage and surgery. High levels also lead to kidney failure because the body cannot handle it. High levels of calcium were detected in his chem panel blood work that was done last week. They also did a parathyroid blood test. The thyroid levels are normal so it's not the thyroid (or whatever was the explanation.) High calcium can indicate cancer but there were no other indications of issues in his CBC/chem panel blood work. We are increasing his water and changing his food to a high protein, low carb, etc. diet. We are also trying additives such as adding potassium, fiber, and a touch of baking soda (which helps the blood change the calcium into a type that can be excreted.) It's again, as with HCM cats, a balancing act. Too much potassium is a bad thing; too much calcium is a bad thing; too much baking soda is a bad thing. We will retest his blood in a couple of months. If it does not come down, we will eventually do scans to make sure he does not have cancer. IHC-Idiopathic Hypercalcemia-is not caused by stress. Curiously, he's on amitriptyline which was used in one study to help restore renal function in cats who suffered from renal failure. Yet, our cat has had urine issues with the med-too high a level and he goes too often as if he had a UTI. Lower levels restore normal function. The other male cat who was on the med, had the opposite reaction-not going enough and holding his urine (urine retention) for 18 hours.
For more information on managing IHC go to-