Chronic Kidney Disease
Chronic kidney disease is a common, progressive decline in kidney function in older cats and dogs that's often silent until well advanced but can be managed with diet and medication.
Also known as CKD, Chronic Renal Failure, Chronic Renal Insufficiency, Kidney Failure
Your pet's kidneys do far more than make urine. They filter waste out of the bloodstream, balance fluids and electrolytes, help control blood pressure, and even trigger red blood cell production. Chronic kidney disease means that filtering capacity has been declining gradually, usually over months or years, rather than failing suddenly. It's one of the most common conditions vets see in older cats and also turns up regularly in older dogs, and because the kidneys have a lot of spare capacity built in, at least two-thirds of kidney tissue needs to stop working before any signs become noticeable. That's why it's often described as a silent disease in its early stages.
Because symptoms show up late, owners frequently mistake early signs for normal aging. The changes to watch for include:
- Drinking noticeably more and producing more urine
- Weight loss, even with a normal or picky appetite
- Lethargy or a general lack of enthusiasm
- Vomiting, bad breath, or mouth ulcers
- Poor coat condition or a drop in body condition
In early stages the main signs are increased drinking and urinating, while as the disease progresses cats tend to lose weight, eat less, and vomit more. None of these are exclusive to kidney disease, which is exactly why a vet needs blood and urine tests, not guesswork, to confirm what's going on.
Vets diagnose and track CKD using blood markers like creatinine and a newer test called SDMA, alongside urine tests that check how concentrated the urine is and whether protein is leaking through damaged kidney filters. Staging is based on fasting blood creatinine or SDMA levels, checked on at least two occasions in a stable, hydrated patient, and the animal is then further classified based on protein levels in the urine and blood pressure. This staging system, developed by the International Renal Interest Society, gives vets a shared framework for deciding how urgently to treat and what to monitor, and it means two pets with the same diagnosis might need quite different care plans depending on how far the disease has progressed.
There's no cure for CKD, but that doesn't mean nothing can be done. Dietary management is considered the cornerstone of treatment, with specialized kidney diets formulated to ease the workload on the kidneys, typically by limiting phosphorus and adjusting protein levels. Depending on the stage, vets may add medications to control blood pressure, protect against protein loss, manage nausea, or support appetite. The overall goal is to slow disease progression, manage symptoms and maintain quality of life rather than reverse damage that's already been done.
If your dog or cat is getting into their senior years, or if you've noticed any of the signs above, it's worth asking your vet about routine kidney screening rather than waiting for symptoms to become obvious. Catching CKD at an earlier stage genuinely changes what treatment can achieve. The guides below go deeper into diagnosis, diet, and day to day management.
