Kidney disease in older cats

Thanks, Cat. She´s had the test now and her urine is still very dilute despite the change to Hills k/d. However, the vet says she is stable as there is no protein or blood in her urine and she has gained about 300g in three months. Also she seems content and comfortable in herself - still plays, goes outside etc. He just wants to test her again in 3 months. He also said that 18 is quite elderly for a pedigree cat.

Hi Cassie,

Testing the dilution of the urine is a very good way of measuring how well the kidneys are functioning. The kidneys job in the body is to filter the toxins out of the blood while conserving as much water as possible. Cat´s kidneys are very good at this, mainly because they are a desert creature by evolutionary standards, and so they produce very concentrated urine. This is why the suffer with a lot of kidney problems as they age, as the kidneys quite literally wear out.

Cats with kidney failure will drink and urinate more, it is often one of the first signs noticed by owners. When the kidneys start to fail, they become less good at conserving water and more is lost in the urine. So, they don´t urinate more because they drink more, as is often assumed, they urinate more (and lose more body water) so have to drink more to replace it. The more dilute the urine, the more advanced the kidney disease and vets will often use a urine dilution test (or specific gravity to give it its proper name) to monitor the disease progression. It is also important to measure the kidneys using a blood test as well but a urine test can be more sensitive and is often a lot cheaper.

Dietary change to a prescription diet such as Hill´s k/d is the mainstay of treatment of kidney disease but other medications such as tablets and food additives can be used, especially as the disease progresses.

I hope this helps you!

Cat