Kidney disease occurs when there is abnormal structure and or function of one or both kidneys. The main functions of the kidney are to remove toxins and waste products from the blood, maintain water and electrolyte balance, and produce a variety of hormones. Acute kidney disease can occur within hours or days while chronic disease is thought to be present for months to years. Chronic kidney disease is irreversible, progressive, and cannot be cured. Although this disease is not curable, some dogs and cats with chronic kidney disease can have their symptoms managed for months to years.
Initial clinical signs of chronic kidney disease include increased drinking or thirst and increased volume of urination. Owners will report having to refill the water bowls more frequently, increased need for dogs to go outside, or needing to change the litter box more often. As the disease becomes more progressive other signs such as weight loss, poor hair coat, lack of appetite, vomiting, oral ulcerations, malodorous breath and anemia can occur.
Anemia occurs due to a lack of a hormone production by the kidneys called erythropoietin that is responsible for red blood cell production by the bone marrow. Chronic kidney disease can also lead to high blood pressure or hypertension. Long-term hypertension can lead to sudden blindness due to retinal damage, stroke like signs (sudden behavioral changes, stupor, dullness or coma), and cause further damage to the kidneys.
Tests used to diagnose chronic kidney disease or failure include routine blood work (complete blood count and chemistry profile) to assess red blood cell counts, BUN and creatinine. The blood urea nitrogen or BUN results can be elevated due to conditions other than kidney disease but is assessed with the creatinine. If muscle mass is low, creatinine can be falsely lowered. Other tests may include a urinalysis to help determine the concentrating ability of the kidneys. A blood pressure will should also be taken. Imaging of the kidneys can also be performed via radiographs (x-rays) or ultrasound to assess the kidney size, shape, and for any mineralization, dilation of the pelvis (inner part of the kidney) or the presence of uroliths.
Treatment of chronic kidney disease includes a kidney friendly diet, hydration therapy, and medications to help control clinical signs such as vomiting. Since pets with kidney disease cannot easily eliminate protein metabolism waste products, low protein diets are often prescribed. Reducing phosphorus levels is also recommended. Special kidney-friendly prescription diets are protein and phosphorus restricted and have been shown to help slow progression of kidney disease. Hydration therapy may include giving subcutaneous fluids or fluids under the skin.
Pets with chronic kidney disease or failure should be routinely monitored by their veterinarian. Although an incurable disease, a good quality of life can be achieved in most patients through diligent monitoring and at home care.