About 1% to 3% of pets have chronic kidney disease, but the percentages increase sharply in older animals—up to 10% of senior dogs and 35% of senior cats. Despite these numbers, many of our furry pals go undiagnosed for long periods before the need for treatment is determined. Unfortunately, the longer the disease goes untreated, the more irreversible damage is done inside the kidneys.

Early detection of chronic kidney disease can change the course of treatment and the ultimate disease outcome, adding years to an affected pet’s life. Recent advances in testing and a focus on standardized diagnostic and treatment guidelines have made early detection more achievable, which is great news for aging four-legged friends. The Haskell Valley Veterinary Clinic team shares their guide to chronic kidney disease and the impact of early detection in pets.

What do a pet’s kidneys do?

The kidneys are a vital organ system in dogs, cats, and many other species, including humans. They interact in complex ways with other body systems, but their main functions are to:

  • Filter waste products from the blood and dispose of them in the urine
  • Conserve water, minerals, proteins, and other important substances
  • Contribute to red blood cell production
  • Contribute to fluid balance, hydration, and blood pressure regulation

What is chronic kidney disease?

Chronic kidney disease (CKD) occurs when individual kidney cells begin to fail and die. As some cells die, others step up and work harder to compensate for the loss, which ultimately leads them to become damaged as well. In this way, CKD leads to the eventual loss of kidney function and decompensation of many body processes. Most pets who develop CKD are older, and the disease is presumed to be a function of age and a lifetime of accumulated damage, but some younger pets can develop CKD if they contract certain infections or have a hereditary disorder. 

What are the stages of chronic kidney disease in pets?

CKD in pets is classified in stages one through four by the International Renal Interest Society (IRIS). IRIS publishes and regularly updates guidelines on the diagnosis, staging, and treatments of CKD in pets so that veterinarians have the most up-to-date information to treat their patients. Stages one and two are considered early stage, while stages three and four are considered late- or end-stage disease.

How do I know if my pet has chronic kidney disease?

During early stage disease, most pets don’t have any outward clinical signs because the remaining healthy kidney cells work overtime to maintain normal function. During later stages, after two-thirds to three-quarters of function is lost, the following signs become apparent:

  • Increased urination and thirst
  • Weight loss
  • Vomiting
  • Poor appetite
  • Bad breath
  • Retinal damage or blindness

How do veterinarians diagnose chronic kidney disease?

CKD is most often diagnosed in later stages because pet owners notice the clinical signs and bring their furry companions in for care. Diagnosis involves a blood test, urinalysis, and sometimes an abdominal X-ray or ultrasound to look at the kidney size and structure. Pets with CKD have elevated waste product values in their blood—blood urea nitrogen (BUN) and creatinine—and watery, dilute urine. They also may leak protein into their urine and have high blood pressure. 

Veterinarians use the test results to determine how advanced kidney disease has become—this is called staging. Along with BUN, creatinine, urinalysis, and blood pressure testing results, a newer test value called symmetric dimethylarginine (SDMA) plays a major role in staging. This test can detect kidney damage long before BUN or creatinine values change, and, while it has been available since 2016 from specific laboratories, it has only recently become more widely used. SDMA testing included as part of a basic blood panel enables earlier detection of CKD.

What impact does early detection have on chronic kidney disease in pets?

The only way to detect CKD in the earliest stages is to include an SDMA test on annual wellness screening blood panels for healthy pets. The SDMA value becomes elevated when 60% of the kidneys are still functioning well, alerting your veterinary team to a problem before your pet gets sick. At this stage, your veterinarian can begin a special diet, avoid medications or adjust doses to prevent additional kidney damage, and start medications or supplements that will help to reduce the workload on the kidneys and preserve their function for many years to come. 

Treatments that begin during later stages are less effective and may not extend a pet’s expected life span. Pets diagnosed with CKD at any stage need regular blood and urine monitoring to evaluate their kidney function and how well their treatments are working. 

Because the causes and origins of CKD in pets are difficult to pinpoint and most likely related to aging and genetic factors, preventing the disease from developing may not be possible. Annual wellness screening tests that include a blood panel with SDMA and a urinalysis can detect CKD in the earliest stages, allowing our Haskell Valley Veterinary Clinic team to implement treatments. Contact us to schedule your pet’s next wellness and preventive care visit or if you have questions about CKD or how early disease detection can affect your furry pal’s health.