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Chronic Kidney Disease in Dogs

Rusty's Story

Rusty's Story and Chronic Kidney Disease in Dogs 

“Rusty” was a beautifully groomed, much loved eleven-year-old Bearded Collie. He had been brought into the clinic as recently he had been noticeably drinking more and he was now asking out to urinate overnight, which was very unlike him. 

Advised blood and urine tests revealed that “Rusty” had chronic kidney disease, likely due to ageing of his kidneys, as he had had no other known underlying health problems previously. 

The kidneys are two of the most vital organs in our dogs’ bodies. They constantly filter blood, removing toxins and make sure that the balance of electrolytes is kept at the right levels. Kidneys principally act to remove waste products from the blood stream, regulate the levels of certain essential minerals, conserve water, and produce urine. 

With Chronic kidney disease (CKD) the kidneys become unable to efficiently filter the blood of their waste products. Most dogs in kidney failure produce large quantities of urine, however the body's toxic wastes are not effectively eliminated. Kidney tissues cannot regenerate if destroyed, and generally at least two thirds of the kidneys must be dysfunctional before any clinical signs are seen. In many cases, this means that the destruction has been occurring for months to years before kidney failure becomes evident. 

There are many different reasons why our dog’s kidneys stop working as well as they should. The most common cause is an age-related degeneration within the kidneys, which slowly worsens over time. Other examples of illnesses that can lead to kidney problems include kidney stones, certain infections (such as Leptospirosis, Lyme disease or Leishmania), kidney cancers, or genetic kidney problems in young dogs. In dogs, chronic kidney disease is most often associated with natural ageing of kidney tissues.  

When the filtration processes in the kidneys become ineffective, the body reacts and blood flow to the kidneys is naturally increased to try to increase this necessary filtration. This results in the production of more urine and so water consumption is increased, and this is called compensated kidney failure. After approximately two thirds of the kidney tissue is destroyed, there is a rise in waste products within the bloodstream and other signs and symptoms of kidney disease are then seen. These clinical signs of more advancing kidney failure include a loss of appetite, weight loss, depression, lethargy, vomiting, diarrhoea or constipation, smelly breath and occasionally mouth ulcers. 

There are two basic tests for kidney function: a complete urinalysis and a blood chemistry analysis. A low urine specific gravity, indicating a dilute urine, is the earliest indication of kidney failure. An increase in protein in the urine, proteinuria, also indicates decreased function. A blood biochemistry analysis is also required, measuring the level of two waste products in the blood, namely blood urea nitrogen, and blood creatinine, as an elevation in these can indicate decreased kidney function. Tests to measure other blood biochemistries, as well as the red and white blood cell counts are also important. A blood test to assess levels of SDMA, a naturally occurring biological indicator for kidney function, is also used. SDMA concentrations increase above the normal reference interval well before the serum creatinine becomes elevated. This helps us detect early renal failure cases, and so provide treatment at a much earlier stage. A dog diagnosed with a low urine specific gravity as well as elevated Urea and Creatinine is said to be azotemic. The IRIS (International Renal Interest Society) staging system is used to determine specific levels of Kidney failure. By using this IRIS staging we can have a better idea of how to proceed with treatments and monitor progress. 

Treatments are tailored according to your dog’s kidney disease levels. Treatments advised are: A special Kidney diet lower in protein levels and low in phosphorus; A phosphate binder; Drugs to help to lower blood pressure within the kidneys; Kidney support supplements, and drugs to assist with secondary abnormal calcium levels and anaemia. 

It is important to always make sure that your dog has plenty fresh water available and add some wet kidney diet and a little extra water to their food at each meal to further increase their fluid intake.  

Typically, chronic kidney failure progresses slowly. However, the prognosis is quite variable, depending on the level of kidney disease present and the dog's response to the advised diet and treatments. 

“Rusty” was checked regularly now, and his blood and urine values regularly monitored. Thankfully, his kidney treatments and diet made his kidney disease more manageable, and he lived a very happy life for a couple more precious years. 

If your dog is showing any of the symptoms of kidney problems, please do get in touch with your vet’s surgery for an initial examination and any tests as required.  The sooner this disease is managed the better for your pet. 

Alison Laurie-Chalmers 
Senior Consultant 
Crown Vets