Overview of Chronic Kidney Disease in Cats
The kidneys are amazing organs within the body that receive 25% of the blood supply. Their job is to filter the blood, so some products are kept, and others are excreted to create urine. Chronic kidney disease often affects our older feline companions but can even be present in our younger feline companions as well. Essentially, in chronic kidney disease, the kidneys have been damaged to a point where they can no longer concentrate their urine appropriately, which leads to numerous clinical signs.
Unfortunately, sometimes the exact cause for chronic kidney disease is never found. There are times when cats are born with kidneys that are dysfunctional such as with polycystic kidney disease or renal dysplasia, which is a form of congenital chronic kidney disease. In these cases, the renal disease may go undetected until their disease has progressed, and they start showing clinical signs. There are other times where the cat may be suffering from another disease that may damage the kidneys over time, or they receive small kidney insults in some other way. This is a form of acquired chronic kidney disease.
Clinical Signs and Presentation
Cats affected by chronic kidney disease will often show progressive signs of lethargy, and a decrease in appetite that may lead up to a complete uninterest in food. They will often also lose weight during this time. These cats will occasionally vomit, but as the disease progresses the vomiting may also increase in frequency. These cats also will drink a large amount of water and urinate frequently.
The diagnosis of chronic kidney disease is often made by running a complete blood panel. The blood work will show an elevation in renal values without an appropriate concentration of their urine. There may or may not be protein present in the urine, which would indicate further renal damage. Depending on the type of blood work being ran, there may be an additional marker that is looked at to assess kidney disease which is a specialized test (SDMA). Chronic kidney disease is such a common disease among our feline patients that once the kidney disease is found, they can then be graded on an IRIS scale based on their blood work findings and blood pressure, which can give a better idea of prognosis. Your veterinarian may also recommend imaging of the kidneys in the form of abdominal ultrasound to evaluate for congenital chronic kidney disease.
Treatment for chronic kidney disease is supportive since there is no cure for this disease. The disease is progressive, but there are therapies that can be used to slow the progression of chronic kidney disease, and drugs that can be used to treat the side effects of chronic kidney disease as it progresses. One of the first therapies recommended is a diet change. These cats often require more potassium in their diets and less phosphorus, so another major therapy used in these cats is used with diet. Increased omega 3 fatty acids within the diet can also help slow the progression of chronic kidney disease. There are many specialized renal diets available at your veterinarian’s office that are buffered and made with a certain ratio of nutrients specifically to meet the needs of cats with chronic kidney disease. These diets help slow the progression of chronic kidney disease. Another therapy used in these cats is hydration when they need it. Since the kidneys can no longer concentrate the urine appropriately often when these cats have another form of fluid loss (such as vomiting) they often cannot keep up with this increased loss and need more fluids. This can be achieved by subcutaneous fluids given at home or intravenous fluids given in the hospital depending on the severity of dehydration. Other therapies for cats with chronic kidney disease are dependent on what other clinical findings develop as their disease progresses, such as increased blood pressure, low red blood cell counts, and protein in the urine.