Chronic renal failure (CRF) can affect a dog of any age, breed, or gender. It is actually a normal part of the aging process, and the average age at which owners begin to notice symptoms is around seven years old.
The kidneys work as a filtration system for the blood, removing waste products through the urinary tract. When they don’t function properly, waste products build up, and clinical signs of kidney disease develop:
- Increased water consumption
- Increased urine production
- Blood in urine or stool
- Lethargy and weight loss
- Loss of appetite or anorexia
- Vomiting
- Loss of muscle tone
- Diarrhea
- Gastrointestinal ulcers
- Bad breath
- Exercise intolerance
- Eventually, urination and drinking will slack as the kidneys are unable to produce urine, and water retention will cause a puffy appearance.
The increase in water consumption (polydipsia) is the body’s attempt to flush out the buildup of toxins. The increased urination (polyuria) is caused by the increased water intake, but the kidneys are unable to concentrate the urine, so it appears almost clear in color with little to no odor.
Symptoms of Chronic Renal Failure in Dogs
Symptoms of CRF usually do not appear until the disease is in an advanced stage, typically when the kidneys are functioning at only 25% of their capacity. By this time, it is often too late for treatment to do much more than make the dog more comfortable and help alleviate symptoms. Dogs with chronic renal failure can live for a few months to a few years, depending on how well they respond to treatment and how quickly the disease progresses.
Although CRF can occur in any dog, certain breeds are more prone to congenital renal failure, which can often develop when the dog is still young. These breeds include Basenji, Beagle, Bull Terrier, Cairn Terrier, Chow Chow, Cocker Spaniel, Doberman Pinscher, German Shepherd, Lhasa Apso, Miniature Schnauzer, Norwegian Elkhound, Rottweiler, Samoyed, Chinese Shar Pei, Shih Tzu, Soft-coated Wheaten Terrier, and Standard Poodle.
Most owners initially notice an increase in thirst but dismiss it as a sign of old age. This often leads them to switch the dog to a senior diet, which, because it is lower in protein, sodium, and phosphate, helps lessen the load on the kidneys. This can alleviate symptoms for anywhere from a few months to a few years. However, when the dog begins to drink excessively again, this time with a marked increase in the quantity and frequency of urination, owners quickly realize there is a problem.
A veterinarian will first perform a physical exam to diagnose the issue. Active renal disease can mask the severity of the condition, so the vet must first address any symptoms through rehydration, correcting pH imbalances, and alleviating any metabolic issues. A physical exam may reveal small or irregular kidneys, weight loss, loss of muscle tone, pale mucous membranes, oral ulcers, and uremic breath. Lab tests will include a complete blood count (CBC), blood chemistry analysis, and urinalysis. X-rays, ultrasound, and urine cultures may also be requested to further diagnose the disease’s stage.
Chronic renal failure is typically idiopathic (occurring as part of the normal aging process) or congenital. However, other conditions and diseases can cause or exacerbate the problem. These include kidney toxins, high blood calcium, inflammation of the internal structures of the kidneys, kidney infection, polycystic kidney disease, kidney stones, chronic urinary obstruction, certain medications, and lymphoma.
Renal diets are not just low in protein; they are also low in salt and phosphorus, which both increase the load on the kidneys by disrupting pH balance and causing water retention and dehydration. Veterinary-formulated renal diets are also high in naturally occurring anti-inflammatory Omega-3 fatty acids, fiber, and vitamin D, all with a neutral pH. These diets are also calorie-dense, so even if the dog’s appetite is off, the diet will hopefully help maintain its weight.
Other treatments may include medications to control nausea, inappetence, electrolyte and mineral imbalances, hormonal deficiencies, and high blood pressure. Subcutaneous fluids—sterile fluids injected under the skin—are often administered in moderate to severe cases. Some severe cases may require more aggressive treatment, including hospitalization.
Chronic renal failure can lead to other medical conditions, such as inflammation and ulceration of the stomach and intestines, anemia, decreased red blood cell counts, urinary tract infections, and systemic hypertension (hypertension combined with CRF often leads to blindness).
Early diagnosis and treatment are critical for dogs suffering from chronic renal failure. Early detection can significantly slow the progression of the disease, allowing your dog to lead a longer, healthier life. If you notice any signs of the disease, schedule an appointment with your vet for a diagnosis and advice on how best to treat the condition.
