Chronic kidney disease (CKD) is a common diagnosis in cats & dogs. As pets age, the likelihood pets will develop kidney disease increases. In fact, over 1 in 3 cats & 1 in 10 dogs will get kidney disease. Worse, dogs & cats show no signs of illness until their kidneys have lost most of their function permanently. It’s a disease for which we have no cure, only the ability to slow it down & manage symptoms. For this reason, we recommend yearly urinalysis & blood tests, especially as pets age.
Our in-clinic SDMA blood test along with urinalysis is a simple way for our veterinarians to screen for & spot early signs of kidney disease in your cat or dog, while there is still time to do something about it. Think of it this way, as we age, we get our cholesterol tested yearly. If the cholesterol is too high, our healthcare providers recommend a lifestyle plan. Similarly, annual labwork is an opportunity for you & your veterinarian to understand your pet’s health more completely. If SDMA levels are elevated, your veterinarian can prescribe a plan that could help preserve your pet’s kidneys. If your pet has kidney disease, SDMA helps us determine how advanced the disease is, enabling your pet to get the right treatment plan while there is still time to impact their quality of life.
The kidney is a remarkable organ. It filters waste products out of blood so that they can be excreted in the urine. They manage the balance of water & electrolytes (salts) in our bodies. They also make a hormone that tells the bone marrow to produce red blood cells, which carry oxygen throughout the body. The kidneys you’re born with are the kidneys you have for the rest of your life. They don’t regrow, & have limited ability to heal. Same applies to pets.
Perfect kidneys function at 100%. In chronic kidney disease, kidneys begin to lose the ability to do the work they need to do. This can be a very slow process, taking years in some cases. As with most things in the body, there’s some redundancy in the kidneys to allow for a certain amount of damage without the body suffering for it. Eventually, however, there’s a threshold after which the kidneys can’t keep up & things start to go very wrong. The end result of damage to the kidneys is that the nephrons (functional units in the kidneys) are destroyed, leaving scar tissue where functioning kidney used to be.
When 2/3 of the kidneys’ functional capacity is gone, leaving only 33% working, the kidneys lose their ability to manage water balance in the body. Water leaves the bloodstream at a rate that will dehydrate the animal. This is the earliest sign of chronic kidney disease. The urine will seem more dilute & pets will begin to drink more water & urinate more frequently. In truth, the urine production goes up because of the inappropriate loss of water, so pets drink more to remain well-hydrated. We can detect this low urine concentration when we run a urinalysis. Sometimes, we can detect protein loss in the urine, as well, which is a sign of trouble. At this stage, pets may begin losing weight.
When 3/4 of the kidneys’ functional capacity is gone, leaving only 25 % working, the kidneys can no longer keep up with the removal of waste products from the blood. Byproducts of metabolism begin to build up in the bloodstream. We can detect these rising values on bloodwork. As these waste products rise, we begin to see effects in the animal. Appetite drops because of nausea & irritation of the stomach lining, followed by vomiting. Dehydration & weight loss occur, as well as significant loss of muscle mass. At very high levels, these wastes can directly impair brain function as well. Other effects of advancing kidney disease can include high blood pressure & anemia. Unfortunately, many of the pets we diagnose come to us at this stage when very little can be done to help the pet.
There are lots of treatments available to manage renal disease, but remember that none of them are a cure. Running lab work is the ONLY way we can detect the emergence of chronic kidney disease.The sooner we start treatment, the better most pets do! Each patient is different in terms of response to treatment & the rate the disease progresses. Some patients survive only a few months. Others can go years before we lose the fight. We manage the patient, with the goal being a good quality of life.
The take-home message here is, RUN ANNUAL LABWORK ON YOUR PETS! It’s the best way we have to watch for early signs so we can begin treatment early.