Detecting The Early Stages of Kidney Disease in Senior Dogs
Diagnosis of Chronic Kidney Disease in Senior Dogs
One of the earliest signs of kidney failure in senior dogs is increased drinking. This increased drinking, medically known as polyuria, is often unexplainable, the weather is not too hot, the dog has not exercised nor has he eaten foods that trigger thirst or is he on medications that increase drinking. Also, known as polydipsia, this increased drinking is basically triggered by special sensors in the brain. When waste products accumulate in the dog's body, the sensors basically realize that the dog's blood is too concentrated and trigger the dog to drink more.
Because what goes in must come out, soon the excessive drinking will transform into increased urination, causing the dog to ask to be let outside during the night (nocturia), or worse, eliminating in the night wetting the bed.
In a healthy dog, kidneys help filter toxins, removing them from the bloodstream and discarding them in the urine. When the kidneys are not functioning properly, they cannot perform these task well and the resulting urine is very dilute as the kidneys are not removing toxins and waste from the body as they are supposed to. When this happens, toxins build up and the body reacts with vomiting and diarrhea in an effort to remove these toxins.
In dogs, kidney disease is often part of the aging process. Indeed, it's often thought to be the result of wear and tear of the kidney tissues overtime. In small dogs, early signs of kidney failure can be sees around ten to fourteen years of age; whereas, in larger dogs they can become noticeable as early as seven years of age.
Did you know?
Over their lifetimes, 1 in 10 dogs will develop chronic kidney disease.
The Issues with Routine Kidney Tests in Dogs
Upon seeing the vet, the first and foremost diagnostic tests run often include a urinalysis and blood tests to determine waste products in the blood.
The urine test often encompasses a Urine Specific Gravity (USpG ) measurement where the concentration of the urine is tested. In kidney failure, the reading will reveal dilute urine of a gravity close to distilled water. A dog's' normal specific gravity measurement ranges between SpG :1.020 to 1.040, whereas a dog with kidney failure will have an SpG of about 1.008 to 1.012. A low urine specific gravity is one of the earliest signs of kidney failure, suggesting that about two-thirds (67%) of the kidney function has been impaired. Additionally, a urine test may show an increase in protein in the urine which can also be suggestive of decreased kidney function
The blood test focuses on looking at Blood Urea Nitrogen (BUN) and Creatinine levels. In normal dogs, BUN levels are rarely higher than 25 to 30 mg/dl. Dogs with renal failure instead often have BUN levels of 90mg/dl or more.
Creatinine in normal dogs is usually less than 1.0 mg/dl, but in dogs with kidney issues may raise up to over 8 mg/dl.
When a dog presents with a low specific gravity, high levels of BUN and creatinine, it's suspected that about three-fourths (75%) of the kidney function is compromised; whereas, low specific gravity, high levels of BUN and creatinine and high levels of phosphorus are indicative of severe kidney failure with about 83 to 87% of kidney function impairment.
The problematic issue with diagnosing kidney problems in dogs is that dogs often show symptoms only once 75% of the kidneys have been damaged and clues about this organ malfunctioning appear only once damage has been done. Consider that according to VCA Animal Hospital, a dog with marginal kidney function may show normal levels of BUN and creatinine (the only sign may be urine with low specific gravity) but should a major stress occur, such as in the case of surgery or disease, kidney failure may take place and send those blood test values up quickly. Early detection of dog kidney disease is difficult, but there are fortunately some innovative options under way.
Innovative Tests for Early Detection
Early detection of kidney disease is very helpful, because in its earliest stages kidney deterioration can be potentially reversed. The problem with early detection is that dogs do not show any signs until the kidneys are already compromised.
One innovative test is the The E.R.D.-Screen™ Urine Test from Heska Corporation. This test is capable of detecting albumin in urine 30 times better than regular dipsticks and prior to BUN/Creatinine showing problems. In humans, it was discovered that small amounts of albumin (microalbuminuria) in the urine were reliable predictors of impending problems. The same phenomenon was detected in dogs, leading to the creation of the ERD screen test by Heska. The test is a simple 5-minute in-hospital test
Another innovative test is the SDMA test by IIDEXX capable of detecting the early stages of kidney disease months or even years earlier than traditional tests. Also known as " symmetric dimethylarginine" this test is based on scores, and a persistent increase in SDMA above 14 µg/dl is suggestive of reduced renal function. According to an article by DVM360, IDEXX representatives claim that SDMA is a biomarker that's highly specific to kidney damage and impairment affecting just 25 to 40 percent of the kidney can be detected. IDEXX is offering this test for free in routine chemistry profiles.
As seen, these innovative tests can be quite helpful in detecting early stages of kidney disease before symptoms arise. With early detection there may be better chances for recognizing problems and granting a better prognosis. For a guide on grading of acute kidney injury in dogs and cats, visit the International Renal Interest Society website.
Disclaimer: this article is product of my research and not meant to be used as a substitute for professional veterinary advice. If you suspect kidney problems in your dog, consult with your vet for proper diagnosis and treatment.
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