Diagnosing Chronic Renal Failure
Dog Breeds
A number of techniques are available to diagnose chronic renal failure in cats. Routine blood evaluations can detect evidence of CRF at an early stage. Most veterinarians recommend that these tests be performed annually on cats at and after 7 years of age.
Read More >
Introduction
Most cats suffering from symptomatic chronic renal failure (CRF) are severely ill. Early diagnosis and treatment may help to delay further kidney damage.
Diagnosis of Feline Chronic Renal Failure
A number of techniques are available to diagnose chronic renal failure in cats. Routine blood evaluations can detect evidence of CRF at an early stage. Most veterinarians recommend that these tests be performed annually on cats at and after 7 years of age. Blood chemistry profiles will identify the levels of circulating waste products, including blood urea nitrogen (BUN), phosphorus and creatinine, which normally are eliminated in the urine by well-functioning kidneys.
Consistently elevated levels of these substances in blood reflect declining kidney function. Anemia, which is commonly associated with chronic renal failure, can also be shown by routine blood work (a complete blood count, or CBC). A full blood panel can also help identify or eliminate other causes of the cat’s clinical signs, such as diabetes or hyperthyroidism.
A urinalysis is a simple diagnostic tool that can provide a great deal of information about a cat’s kidney function and overall health. The results of a urinalysis can identify a urinary tract infection and can also measure the concentration of the cat’s urine. Cats in chronic renal failure usually drink large amounts of water and urinate frequently, because their body is trying to flush excess waste products out of circulation. Reduced kidney function affects the kidneys’ ability to concentrate urine. As a result, very dilute urine is a common sign of chronic renal failure.
A thyroid panel (run on a blood sample) is often recommended in aging cats to rule out hyperthyroidism. Hyperthyroidism may exist apart from or in conjunction with renal failure, and if it is present the treatment options may change. Because many cats with CRF have high blood pressure (hypertension), their blood pressure is usually routinely monitored.
When chronic renal failure is suspected, the veterinarian may recommend an abdominal ultrasound to obtain an in-depth look at the cat’s kidneys. This procedure is painless and non-invasive, and the results can provide a great deal of critical information about the kidneys’ functional status. Ultrasonography also may disclose other related or unrelated abdominal abnormalities. Abdominal radiographs (X-rays), with or without use of injectable dye, can show abnormally small or enlarged kidneys, which often are associated with CRF. These procedures may also provide information about the actual cause of the cat’s disease, such as kidney or ureter stones (nephroliths, ureteroliths), tumors, cysts or other forms of physical obstruction.
Surgical biopsy of the kidneys can be used in appropriate patients to identify the extent of kidney damage. However, kidney biopsies are not routinely taken in cats. The most common use of this diagnostic tool is when the cat’s kidneys are enlarged (renomegaly) or to rule out neoplasia (cancer; especially lymphoma), feline infectious peritonitis (FIP) and other conditions.
Special Notes
While it is important to diagnose CRF accurately, unfortunately there is no cure. Treatment options are limited to managing the symptoms and trying to delay progression of the disease.
Treatment Options
Symptoms and Types