Kidney disorders can occur for a variety of different reasons and can affect cats in a number of different ways. Kidney disorders can be genetically influenced or be secondary to another underlying medical condition. They also can be caused by exposure to toxins or simply be a result of the normal process of aging. Kidney diseases tend to be categorized into those that occur acutely and those that are more chronic in nature.
Chronic Kidney Disorders in Cats
Chronic kidney disease, which can progress to chronic renal failure (CRF), results from long-term insult to the kidneys which, over time, damages their ability to adequately concentrate urine and remove nitrogenous wastes from circulation. Chronic kidney disease can be caused by trauma, congenital abnormalities (existing at birth), urinary tract obstruction or infection, kidney stones, polycystic kidney disease, exposure to toxins (drugs, plants, venom, chemicals), lymphoma, and a number of other kidney-specific disorders that your veterinarian can discuss with you if they pertain to your cat (glomerulonephritis, pyelonephritis, tubulonephrosis, amyloidosis, tubulointerstitial nephritis, etc.). Underlying medical conditions such as diabetes and feline infectious peritonitis can also cause chronic kidney problems in cats. Chronic kidney disorders are particularly devastating for owners because by the time clinical signs become apparent, the cat’s kidneys usually are already irreversibly damaged.
The clinical signs of chronic renal disease are a result of the body’s attempt to compensate for the kidneys’ diminishing ability to flush toxins out of the body – which is one of the primary functions of these organs. Among the early signs are “polyuria” and “polydipsia,” which mean dramatically increased urine output and excessive thirst manifested by dramatically increased water intake. Other signs that owners commonly notice are anorexia/inappetance, weight loss, vomiting, diarrhea, lethargy, halitosis (bad breath), seizures, bleeding/clotting problems, poor hair coat, weakness, depression and altered states of consciousness. In severe cases, affected cats may develop high blood pressure (called hypertension), with the adverse effects associated with that condition.
Polycystic kidney disease is a common chronic kidney disorder in cats that is genetically inherited. Persians, and other long-haired cats related to Persians, are most commonly affected by this disease, which typically affects both kidneys. Polycystic kidney disease is a disorder in which large portions of normal kidney tissue are displaced by multiple cysts. These cysts usually are not detected until they become large enough and numerous enough to contribute to either abdominal enlargement or actual renal failure. Bacterial infection of renal cysts has been reported in cats. There is no “cure” for this disease, but medication can help to manage its progression.
Acute Kidney Disorders in Cats
Obviously, the signs of acute kidney disorders appear suddenly. Acute kidney problems must be treated immediately and aggressively to prevent permanent kidney damage. However, if appropriate treatment is provided quickly, it is quite possible to prevent permanent kidney damage. Acute kidney disorders can be caused by venomous snake or insect bites, shock, bacterial and viral infections, exposure to or ingestion of renal toxins such as antifreeze, and trauma from an accident or other physical injury. The signs of acute-onset kidney disorders parallel those caused by chronic kidney damage and include lethargy, depression, vomiting, anorexia, collapse, abdominal discomfort, oral ulceration and bad breath. Another common sign is the absence of normal urination.
If your cat shows any of these signs, see your veterinarian as soon as you can. While chronic kidney damage is not reversible, acute renal damage typically can be resolved if the cause of the insult is identified and rectified promptly. Your veterinarian can perform a series of tests to assess kidney function and diagnose kidney disease.