Canine Kidney Disease



Kidney disease, also known as renal disease, is a common occurrence and can develop in two ways – acute or chronic. Acute kidney disease can show signs within a matter of days and can be very severe. Pets can develop acute kidney problems as a result of ingesting toxins such as antifreeze, certain medications, and tainted foods. Another cause includes decreased blood flow or oxygen delivery to the kidneys, infections, and urinary obstruction. Chronic kidney disease can have a very slow onset and include nonspecific signs – by the time the symptoms have become obvious, the condition is generally unable to be treated effectively. Often, the kidneys will find ways to compensate as they lose functionality over time.

Kidneys are critical to health as they maintain normal concentrations of salt and water in the body, control blood pressure, aid in calcium metabolism, and sustain phosphorous levels. Additionally, the kidneys manufacture a hormone that encourages red blood cell production and filter out the body’s waste through urine. When the kidneys fail, toxins begin to build up in the blood, which can lead to a variety of health issues. While chronic renal failure cannot be reversed or cured, treatment and management aimed at reducing the contributing factors can slow its progression.

Causes

  • Viral, fugal, or bacterial infections
  • Age (organ failure)
  • Parasites
  • Lymphoma
  • Amyloidosis (abnormal deposits of protein in the kidney)
  • Autoimmune diseases
  • Trauma
  • Urinary blockage
  • Diabetes
  • Toxic reaction to poisons or medications (such as antifreeze)
  • Congenital and inherited disorders

Breeds that are most commonly prone to renal failure include:

  • Samoyed
  • Bull Terrier
  • Cairn Terrier
  • German Shepherd
  • English Cocker Spaniel

Symptoms

  • Vomiting
  • Lethargy/depression
  • Weight loss due to lack of appetite
  • High blood pressure
  • Change in water consumption (increased thirst)
  • Increased frequency of urination
  • Mouth ulcers, breath odor, pale gums
  • Swelling in the limbs
  • Enlarged abdomen due to accumulation of fluid
  • Acute blindness
  • Seizures
  • Blood in the urine (hematuria)

Diagnosis

Your dog will undergo a complete blood profile to determine if acute or chronic kidney failure is present. Dogs with renal failure may have anemia, abnormal electrolyte levels, and elevated blood pressure. The levels of certain protein enzymes and chemicals such as creatinine and blood urea nitrogen (BUN) will also be high. As proteins are broken down during the digestion process the kidneys filter out waste products that are of no use to the body. If the kidneys are not functioning properly, this waste builds up and goes into the blood stream.

Azotemia is the term for an increase in blood urea nitrogen or creatinine. Azotemia is divided further into prerenal, renal, or postrenal causes. Prerenal azotemia is due to causes other than actual kidney malfunction that decrease the blood flow to the kidney. These causes include dehydration, Addison’s disease, or heart disease. Renal azotemia occurs when there is damage to the kidney itself, and can include chronic or acute renal disease. Postrenal azotemia occurs when there is a build-up of pressure in the urinary system, which can be caused by a blockage of the urethra.

A complete blood count test is useful to check for anemia and indications of infection. Anemia in renal failure is common and results from a decrease in the production of erythropoietin – a hormone that tells the body to produce more red blood cells – by the diseased kidney.

X-rays may be used to determine the size and shape of the kidneys, as small kidneys are more common in chronic kidney disease while large kidneys may indicate an acute problem. An intravenous pyelography (IVP) is a specialized type of x-ray commonly used to determine kidney issues. A dye is injected into the veins and monitored via x-ray to see if the kidneys filter it out.

Treatment and Management

Your dog’s prognosis will depend on the severity of the disease and its stages of progression. The best way to manage this disease is to follow through with the treatments your veterinarian prescribes.

Acute Kidney Failure
Treatment of acute kidney disease first involves determining the cause. Infections are treatable as are parasites that can reside in the kidney. Exposures to toxins such as Easter Lily and antifreeze are treatable providing the cause is discovered quickly. Initial treatment involves rehydrating the patient – this is typically done with intravenous (IV) fluids. Often enough, the IV fluids are enough to start or increase urine output, but if the output is still not normal, medications such as furosemide or mannitol may be given to get the kidneys functioning. Kidney dialysis, if available, can be used on those pets that fail to respond to routine therapy. This may include cases of nephrotoxin (poison induced kidney failure), pets that are not producing urine, or those requiring emergency surgery for repair of trauma induced kidney failure.

Chronic Kidney Failure
Dogs suffering from long-term kidney failure will often undergo fluid therapy to assist with dehydration as maintaining hydration is critical. You will need to ensure your dog always has an adequate amount of clean drinking water. As the disease progresses, addition fluid in the form of subcutaneous (SQ) fluid may be necessary – owners can typically give these fluids at home after being shown how at the veterinary clinic. The addition of potassium to the fluids or to the diet may be necessary to maintain proper levels of electrolytes in the body.
Although there is no cure for chronic renal failure, there are numerous steps that can be taken to minimize the symptoms and slow the progression of the disease. Diet change, for example, replacing large amounts of poor quality protein sources (meat by-products, cereal grains, etc.) with smaller amounts of high protein such as fresh meat, whole eggs, and milk protein isolates such as casein or whey can provide the amount of protein that is required to maintain nitrogen equilibrium in the pet. The diet should also contain a higher level of potassium and polyunsaturated fatty acids like omega 6 and omega 3 fatty acids. Phosphorus binders and vitamin D supplements are often given to pets with chronic renal failure in an attempt to improve calcium and phosphorus balance and to reduce some of the secondary effects of renal failure. Depending on conditions, medications such as enalapril or erythropoietin may be considered.

Blood pressure should be monitored to help prevent further damage to the kidneys, which could cause an increase in progression of the disease as well as damage to the retinas in the eye, which can result in blindness. Medications may be necessary to maintain normal blood pressure.

With treatment, pets with chronic renal failure may live months to years – it will all depend on how the body responds to the treatment and other health concerns that might arise.

Prevention

Feeding a biologically appropriate diet throughout your pet’s life and maintaining good oral health will go a long way towards keeping the kidneys healthy as well as providing plenty of fresh water and eliminating potential toxins from your dog’s environment.

This material is provided for educational purposes only and is not intended to diagnose or treat any disease or condition.  All specific treatment decisions must be made by you and your local, attending veterinarian.

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