Chronic renal failure, aka chronic kidney disease (CKD), can affect dogs or cats but is more common in cats. Over their lifetime, 1 in 3 cats and 1 in 10 dogs could develop CKD. It is typically seen in elderly animals and is usually caused by the wear and tear of aging, although I believe that diet plays a role. How do you know if your pet has it and what is the best treatment plan? To understand CKD we must first explore how normal kidneys function.
Mammals have 2 kidneys on either side of the abdomen, just under the spine and behind the rib cage. These organs have lots of duties and play a role in maintaining red blood cell levels, maintaining appropriate blood pressure and removing toxins and waste products from the body. While kicking waste and toxins out of the body, the kidneys are also tasked with holding on to as much water as they can.
The good news about the kidneys is that under normal circumstances, animals have a lot of reserves in kidney function. Think about it; a person can donate a kidney (which represents ½ of total function) and do just fine. The bad news is that kidneys do not easily regenerate. Once the function is lost, we can’t seem to get it back. You just can’t un-cook a hardboiled egg.
As the kidneys start to fail, they start to leak protein into the urine and lose the ability to hold on to water. This causes the pet to produce more urine – a condition called polyuria or PU. The loss of water causes the pet to have to drink more – a condition called polydipsia or PD. Usually the first signs of CKD are what doctors call PU/PD.
It is important to realize that the loss of water in the urine is causing the animal to drink more and not vice versa. If you think your pet is drinking too much, and take away his water, you may cause dehydration which adversely affects the kidneys. It is imperative that pets with CKD have unlimited access to water.
As CKD progresses, the animal will often lose his appetite and may vomit frequently. This leads to weight loss and weakness. Complicating issues, in the final stages of kidney disease, the pet may become anemic (low red blood cell count). If left to run its course, CKD basically leads to death by starvation.
Until recently, the test result to indicate CKD the earliest was an elevation in the urine protein level. This typically happens when 2/3 of the kidney function is lost. When ¾ of the kidney function is lost, the blood urea nitrogen (BUN) and Creatinine start to elevate.
In the past year, a new test has been made available. It can detect CKD up to 1 ½ years before the BUN and Creatinine tests elevate. The new blood test measures symmetric dimethylarginine (SDMA) which is a bodily waste product that is almost exclusively excreted by the kidneys.
Unfortunately, conventional vets don’t know what to do with this new test. If an otherwise normal pet has an elevated SDMA, we don’t know if it will necessarily lead to CKD. From a holistic point of view, if the kidneys are starting to have problems, there are things we can do.
If you’re concerned about CKD, read next week’s blog for further insight into prevention and treatment. ***Hint – prescription kidney diets are not usually appropriate.