Diagnosing Canine Kidney Failure

When your dog is ill, diagnosing dog kidney failure can be a long and trying process. The kidneys remove waste from the body, regulate the fluid and electrolyte balance, and assist in maintaining bone health. The kidneys can be severely diseased, with toxins beginning to accumulate in the blood, yet urine output will continue to remain unchanged for a time. Because it takes time for symptoms to manifest, you may think your dog is urinating fine, while his kidneys are not functioning well.

Symptoms of Canine Kidney Failure

Canine kidney failure can take two forms. The first is the acute form, and usually comes on from a sudden event such as poisoning, trauma or dehydration from another illness. The second type, called chronic renal failure, or CRF, is the slow, gradual loss of kidney function over time. The acute form can affect dogs of any age, while the chronic form usually affects older dogs or dogs with diabetes. In CRF, the symptoms may not be present until the more advanced stages of the disease, due to the gradual progression of the condition.

Symptoms of dog kidney failure are many and varied. There may be signs of dehydration with increased water consumption. Urination may be frequent or diminished. Very frequently the appetite is diminished as the body attempts to reduce the toxin loads that come from the normal digestion of proteins. Additional symptoms include:

  • Discolored teeth
  • Muscle weakness
  • Lethargy
  • Mouth ulcers
  • Shivering
  • Diarrhea
  • Vomiting

Diagnosing Canine Kidney Disease

The only definite way to determine if your dog has renal failure is to take him to the vet for an examination. The most frequent and sensitive test to make the diagnosis is by obtaining a blood test for blood urea nitrogen (BUN) and blood creatinine. While BUN can be a sensitive indicator of kidney function, it can be elevated by dehydration, or the amount of protein present in the diet. Normal BUN is around 25 mg/dl but can be present at levels of 300 or more. The goal of treatment is to have the BUN at a level that is less than 80 mg/dl.

Creatinine is eliminated exclusively by the kidneys. It is not affected by the level of hydration, and even less by the protein consumption. Normal values for this substance are less than 1.4 mg/dl. Symptoms of illness begin to appear at around 5.0 mg/dl, so the goal is to keep these levels below 4.5mg/dl to keep the dog feeling his best. Other blood tests will examine the levels of potassium and phosphorus in the body. Levels that are too high can lead to further complications.

The vet will also want to complete a urinalysis. It may also be necessary to run some x-rays or an ultrasound. Your vet may also feel the need to biopsy a sample of kidney tissue if the cause of the decline in renal function remains unclear. Once the cause has been determined, a proper treatment regimen can be taken to restore kidney function, or preserve remaining kidney function.

Dogs with kidney failure can have months or even years of quality life remaining, provided that the disease is diagnosed early enough, the cause is removed or managed, and treatment initiated.