What are the causes of high calcium levels in cats?

My cat has been lethargic and very clingy. Normally he likes to play and is very independant. He's eating and drinking a little more than usual. I took him to the doctor and ran bloodwork-his calcium levels are high and his kidney levels are in the high range of normal. I can't afford to do xrays and a urine analysis because he would need to be boarded for the day and sedated (he's not the nicest boy in the world).

milk maybe!

He could have any number of ailments. It could also be his diet. I recommend placing him on Science Diet KD for cats.

In cats, high calcium levels associated with cancer do occur.. Some sources say that cancer is the most common cause of high calcium levels in cats but I think that the most common current view is that high calcium levels in cats is just about equally likely to be due to chronic renal failure. In a study by Savary, et. al., reported in a recent issue of the Journal of Veterinary Medicine, stones in the urinary tract (uroliths) were also a common cause of high calcium levels in cats. Lab error and primary hyperparathyroidism are the other causes of high calcium levels in cats. It is important not to overlook lab error as a possibility before making any decisions based solely on high calcium levels in the blood stream. Checking carefully for any evidence of calcium oxalate stones in the urinary tract (X-rays usually show these stones if they are present), rechecking the serum calcium level, using an ionized calcium test, if possible, would also be a good idea. The ionized calcium more accurately reflects the "real" calcium level in the blood stream and can help your vet distinguish between the possible disorders that lead to high calcium. Checking the parathyroid hormone levels is also a good idea, so your vet is ahead of the curve having already sent off for that test. In cats, the parathyroid glands are enlarged enough to palpate when there are parathyroid tumors, so feeling the neck region for evidence of lumps is a good idea, too. There is enough elevation in the kidney values reported to make kidney disease a real possibility in your cat. While this isn't as good as nothing being wrong, as would be the case with a lab error, it is better than cancer. There is a lot of information on our site and on the feline chronic renal failure site we have a link to on our link page and reviewing that would be a good idea. It is hard to be patient and wait for lab results but it is necessary. Keep working with your vet to sort through this problem. I am hoping the outcome will be better than you are fearing.

milk or fish in the foodDO NOT FEED SCIENCE DIET as one reader suggested - this food is actually very low quality but by cleverly marketing through vets it has become over priced and often is "thought" to be a better quality than it is... seriously look on the ingredient list and see for yourself byproducts means BEAKS FEET and FEATHERS - also by-products are bad because they are preserved with a chemical pesticide called ethoxyquin

There are various causes of high calcium or hypercalcemia in a cat. None of these include milk or fish. Diet is a very very rare cause of hypercalcemia. Some causes include lymphosarcoma, bone tumors, fibrosarcomas, and probably the most common cause in cats is kidney failure. To diagnose kidney failure it is important that your cat has an urinalysis done. This test will help determine the severity of kidney disease if present. Even though your cat's kidney values were slightly elevated there are other causes for the change such as dehydration, or an urinary tract infection. A urinalysis would allow the veterinarian to determine the kidney's ability to concentrate urine which is one major function of the kidney. If the urine was dilute that may be an indication that the kidneys are in dysfunction hence kidney failure. X-rays would be helpful to determine shape size and if there are any kidney stones present. But the best test would be an ultrasound of the kidneys. It is important that your cat's hypercalcemia is treated because high levels of calcium are toxic to the kidneys and can lead to the formation of bladder stones which can cause a urinary tract infection. It can also cause cardiac problems and overall generalized weakness in your cat. You should ask your veterinarian if there is a payment plan such as Care credit so your cat can be treated.