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Managing Chronic Kidney Disease in Dogs

By Dr. Gail Mason, DVM, MA, DACVIM | Jun 01, 2021

A diagnosis of chronic kidney disease (CKD) can be heartbreaking for an owner. Many owners assume that the diagnosis of chronic kidney failure means that the kidneys are not working. In most cases, chronic renal failure is not the inability to produce urine, but rather a reduced ability to adequately filter toxic waste from the bloodstream. The cells in the kidney cannot regenerate and at least two-thirds of the kidney tissue is malfunctioning before any symptoms are noted. In many patients this results from slow destruction of the kidney tissue over months, to even years. As discussed in our previous article, causes include toxins, trauma, infections, or a result of normal aging process. Can anything be done to extend your dog’s life? Yes, with appropriate treatment and management your dog may live many months or years.

The kidneys not only filter waste, but they also regulate blood pressure, blood sugar, water composition in the blood, pH levels, and influence red blood cell production. Consequently, your dog may have a dilute urine, elevated blood urea nitrogen (BUN), increased levels of creatinine and phosphorus in the bloodstream, anemia, decreased potassium levels, and elevated blood pressure. Your veterinarian can create an effective treatment plan which may include medications, nutritional supplements, specific dietary recommendations as well as possible fluid therapy.

Hypertension: is relatively common in dogs with CKD. The diseased kidneys have a reduced ability to regulate sodium levels in the body. This results in sodium retention and an increase in both blood volume and pressure. Hypertension can accelerate kidney damage, as well as cause damage to the retinas of the eyes. Medications including “ACE” inhibitors such as benazepril or enalapril or calcium channel blockers, such as amlodipine can be effective in controlling hypertension.

Azotemia (increased BUN/creatinine): is the result of inadequate filtering of nitrogenous waste from the bloodstream. Azodyl® is a nutritional supplement that can reduce BUN levels, while Epakitin® and/or aluminum hydroxide can be utilized to reduce blood phosphorus levels.

Gastritis: (inflammation of stomach) is not uncommon in dogs with azotemia. Your veterinarian may recommend acid-blockers such as famotidine (Pepcid®) or acid pump inhibitors, such as omeprazole (Prilosec OTC®).

Calcium dysregulation: can be a significant issue for CKD patients. In a normal dog, the calcium to phosphorus ratio is tightly regulated at 2:1. Since CKD patients have elevated phosphorus in the blood, the body attempts to maintain the ratio by increasing blood calcium levels. To do so, it must remove calcium from bones. Over time, this causes the bones to become very brittle and at risk for fractures. Calcitriol (active vitamin D3) may be prescribed to increase calcium absorption from the intestinal tract, thereby abating calcium resorption from healthy bones.

Anemia: is caused by a deficiency in the hormone erythropoietin, which is manufactured by the kidneys. Chronic anemia commonly manifests as weakness, fatigue, and exercise intolerance. Under close veterinary supervision, injectable synthetic hormones erythropoietin or darbopoietin can be helpful in reversing these symptoms.

Hyporexia (decreased appetite): because of the blood toxins, your dog’s appetite may decrease over time. This can be complicated by nausea, and /or vomiting. Anti-nausea drugs such as ondansetron (Zofran®) and maropitant (Cerenia®) are safe and effective. Mirtazapine (Remeron®) can be used to directly stimulate your dog’s appetite.

Dehydration: can be extremely detrimental to CKD patients. Home fluid therapy may be recommended for your dog to prevent dehydration and continually flush toxins from the bloodstream. This most commonly is done by administering prescribed fluids subcutaneously (under the skin). While this technique is very safe and beneficial, some patients may not be cooperative. The technique has somewhat limited benefit in large breed dogs, due to the amount of fluid volume that would be required.

Dietary management of chronic kidney disease has improved tremendously over the last few years. An appropriate diet can help promote kidney function, reduce biochemical abnormalities, and significantly extend the good quality life of your dog. In a perfect world, we would want a diet that reduces uremic toxins, controls high blood pressure, maintains calcium/phosphorus balance, maintains proper potassium levels, and reduces inflammation (using omega fatty acids). Oh, and of course we want the diet to be palatable to the dog!! Because many blood toxins in CKD patients result from the processing of protein, a protein- restricted diet is often recommended. While this can reduce the work of the kidneys and the amount of nitrogenous waste, we recommend checking with your veterinarian to see if a protein-restricted diet is the right choice for your dog. Fortunately, there is a good selection of prescription renal diets available for dogs in a variety of forms and textures.

Veterinarians are often asked the value of home cooking for a pet with kidney disease. As you can see, the metabolic complications of chronic kidney disease are significant and home-cooking an appropriate diet is a complicated task. For those owners who wish to pursue this option, I recommend consulting with your veterinarian or a specialist in the American College of Veterinary Nutrition. With you as your dog’s health advocate, your dog can continue to live his best life!

 

Dr. Gail Mason, DVM, MA, DACVIM

Staff Internist, Portland Veterinary Emergency & Specialty Care