KIDNEY DISEASE/RENAL FAILURE

Kidney (renal) failure occurs when a dog’s kidneys are no longer able to remove waste and concentrate urine. The bodies of animals produce toxins all day, everyday, and the toxins circulate to the kidneys to be dissolved in water, filtered out and excreted through urination. A healthy kidney makes highly concentrated urine, meaning a large amount of toxins can be handled and excreted in a relatively small amount of water. A failing kidney, by contrast, needs more and more water to excrete the same amount of toxins. A dog in kidney failure will drink increasing quantities of water, until eventually he simply can’t drink enough and toxin levels in his bloodstream begin to rise.

Stages of Chronic Kidney Disease based on Creatinine value
Table based on IRIS guidelines found at www.iris-kidney.com

  At risk for kidney disease (based on breed risk, abnormal urine concentration, urine protein loss, increasing creatinine values, etc.) Stage 1
(Pre-failure)

*no signs
Stage 2
(Mild failure)

*no signs
Stage 3
(Mod failure)

*no signs or mild signs
Stage 4
(Severe failure)

*moderate or severe signs
Dog: <1.4 <1.4 1.4-2.0 2.1-5.0 >5.0

 

Acute Renal Failure Signs and Symptoms

When kidney failure is acute, symptoms come on quickly and are often severe. The top three to watch for are:

  • Vomiting
  • Complete loss of appetite
  • Marked lethargy

Other symptoms you might notice:

  • Straining to urinate and decreased urine production
  • Disorientation
  • Physical weakness; loss of coordination

Acute Renal Failure is a very serious, life-threatening situation and fast action is required if there is to be any hope of saving your dog’s life.

Chronic renal failure is one of the most common diseases seen in older dogs, right up there with arthritis and cancer. Unfortunately, by the time most dogs show signs of kidney disease, much of the irreplaceable tissue needed for good renal function is already destroyed. Many pet owners mistakenly think that as long as their dog is peeing a lot – often more than he did in his younger years, in fact – his kidneys are still working well. In fact, the opposite is true. A dog with developing kidney disease will feel the need to drink and urinate more in an effort to keep his body free of waste – a job his kidneys once did with a whole lot less effort. This cycle of over drinking and over urinating will work for a while, but eventually, no amount of water will be enough to get the job done. By the time your pet starts showing other obvious signs of illness, for example lack of appetite, weight loss or low energy level, significant irreversible kidney damage has occurred. Additional symptoms of CRF, which unfortunately are symptoms of many other conditions as well, include:

•Decreased or lack of urination
•Urinating during the night
•Bloody urine
•Vomiting and/or diarrhoea
•Hunched posture; reluctance to move
•Poor coat condition

Chronic kidney disease can also cause:
•Mouth ulcers and bad breath from a buildup of toxins in the bloodstream
•Dehydration
•High blood pressure, which can result in changes in the retina of the eyes •Anemia as a result of decreased red blood cell production
•Smaller than normal, enlarged and/or or painful kidneys
•Fluid retention in the limbs and abdomen Treatment Options If your pup’s CRF is caused by some factor other than damaged kidneys -- for example a disease that decreases blood flow to the kidneys or a urinary tract obstruction.

It is possible the problem with the kidneys can be reversed with appropriate treatment of the underlying cause. If the disease is the result of irreversible kidney tissue damage, in many cases renal function will stabilize for weeks or even months at a time. And while the disease will progress and kidney function will continue to deteriorate, your pet’s symptoms can be minimized with supportive treatment. Fluid therapy is a cornerstone of treatment for dogs with kidney failure, primarily to prevent dehydration due to the large amount of water that is passed out of the body. Subcutaneous fluid delivery may be necessary, and many pet owners can do this at home after some instruction by their vet. Potassium is often added to the fluids or the animal’s diet to safeguard against muscle weakness and heart rhythm disturbances that result from low electrolyte levels. In some cases, IV fluids may also be required. Your dog should have round-the-clock access to fresh, clean water. Withholding water, for example overnight, will not solve your pet’s need to urinate in the middle of the night and could cause a real health crisis. You’ll need to keep careful track of the amount of food and water your pet consumes each day. If consumption decreases, additional fluids must be administered to prevent dehydration. You should also weigh your pet at least weekly to insure she’s getting enough calories to maintain her weight and proper hydration. The food you feed your dog with CRF is also critically important for disease management and overall well-being. A reduced amount of high quality protein and high moisture content are essential, but phosphorus intake must be restricted. Since phosphorus is found primarily in high protein food sources, you can quickly see the need for expert guidance on how to best nourish your pet. Your integrative/holistic vet is your best resource for advice on the right diet for your pet’s condition, and also what supplements, medications if necessary, and other therapies will help sustain your dog’s health and quality of life.

The best diet depends on the stage of kidney disease present as one specific kidney diet does not fit all stages of kidney disease. For early stages of disease, prescription kidney diets may be too restricted and possibly lead to protein malnourishment and muscle loss. However, with advancing kidney failure, certain dietary modifications have been proven to help pets live significantly longer with less obvious signs of illness. It has never been proven which components of prescription kidney diets are most beneficial to pets, but an overall positive diet effect is seen as pets advance through the stages of kidney disease. It is important that you understand the nature and severity of your pet's kidney condition before selecting a suitable diet.

Characteristics of an ideal kidney diet for pets:

  • Canned pet food has a high water content (70-80% moisture) when compared to dry food (10-12% moisture), therefore dehydration is more likely to occur in pets eating a dry food diet. Canned food will increase a pet's daily water intake and improve overall hydration.
  • Reduced levels of sodium to help maintain normal blood pressure. Mild to moderate sodium restriction (0.1 up to 0.5% sodium on dry matter basis) is usually recommended.
  • Increased levels of Omega-3 fatty acids to decrease inflammation and support kidney health.
  • Increased levels of B-vitamins to compensate urine losses of these water soluble vitamins.
  • Added antioxidants to control cell damage and to promote a healthy immune system. Antioxidants commonly used in pets with kidney disease include: vitamin E, vitamin C, beta-carotene and lutein.
  • Decreased phosphorus to maintain healthy kidney function — depending on the stage.
  • Decreased levels of protein to help reduce kidney workload — depending on the stage.

The ideal amount of protein to feed dogs and cats with kidney disease is a hotly debated topic and is controversial. Prescription kidney diets are formulated with 13-18% protein (on a dry matter basis) for dogs. While evidence suggests restricting protein in the more advanced stages of kidney disease helps pets feel better, there is nothing to support protein restriction in early cases. In fact, protein restriction may lead to protein malnourishment and loss of muscle mass in pets with early kidney disease. This is especially common in cats who have much higher protein requirements than dogs.

Studies have failed to prove that restricting protein slows the progression of kidney disease in dogs and cats. Therefore, my recommendation is to continue feeding a high-quality, highly digestible protein source during the early stages of kidney disease (stage 1 and 2) when a pet has no outward signs and then restrict protein in the more advanced stages of kidney disease (stage 3 and 4).