The Four Stages of Chronic Kidney Disease

Chronic Kidney Disease (CKD) is a common disease in cats, especially senior cats. There are a number of different terms used for this condition, including Chronic Renal Failure, Chronic Kidney Insufficiency, or simply Kidney or Renal Disease. All of them mean that the cat’s kidneys are not functioning optimally.

CKD is different from acute kidney disease, which can strike at any age and is caused by a sudden event, such as ingestion of antifreeze, blood clots, a bacterial infection or kidney stones.

Healthy kidneys act like a filter to remove waste products from the body. They regulate electrolytes such as potassium and phosphorous, and they produce erythropoietin which stimulates red blood cell production. Kidneys produce rennin, which contributes toward regulating blood pressure. Kidneys also play a major role in turning vitamin D into its active form, which controls calcium balance in the body.

When kidney function becomes compromised, cats may not even show symptoms at first. However, the disease is progressive and damage is irreversible, which is why early diagnosis and intervention is so important.

Diagnosing CKD

Your vet will run a blood chemistry panel and a urinalysis to measure the concentration of the urine. Urine concentration decreases as kidney function is lost. Your vet may also recommend additional tests to rule out infection.

Stages of CKD

Once kidney disease is diagnosed, it is “staged,” which means a determination is made, based on lab values, about how much the disease has progressed. There are four stages of CKD.

Stage 1

The creatinine level in the blood (a measure of how well kidneys are performing) is lower than 1.6, which means that less than 66% of kidney functions have been lost. Cats will most likely not show any clinical signs while in Stage 1.

Stage 2

The creatinine level is between 1.6 and 2.8, which means that 66% to 75% of kidney function has been lost. Clinical signs are usually mild or absent at this stage.

Stage 3

The creatinine level is between 2.9 and 5.0, which means that 76% to 90% of kidney functions has been lost. At this stage, typical signs of kidney disease, such as increased thirst and urination, weight loss, lack of appetite, and weakness, are usually noticeable. At this stage, cats may benefit from subcutaneous fluid administration to support remaining kidney function and prevent dehydration.

Stage 4

The creatinine level is higher than 5.0, which means that at least 90% of kidney function has been lost. At this end stage, cats are usually very sick. Loss of appetite, poor grooming and lethargy may be very pronounced. Cats may need more frequent fluid administration.

For a more detailed and indepth look at the stages of CKD, take a look at the IRIS (International Renal Interest Society) Staging Guidelines.

Treating CKD

There is no cure for CKD, but proper treatment can keep cats happy and healthy for quite some time after diagnosis, in some cases, for years. Therapy is aimed at minimizing the buildup of toxic waste products in the bloodstream, maintaining adequate hydration, addressing disturbances in electrolyte concentration, supporting appropriate nutrition, controlling blood pressure, and slowing the progression of the disease.

Once your cat has been diagnosed with CKD, you should work closely with your veterinarian to monitor the progression, but always keep in mind that you’re treating the cat, not the lab values. Even though your cat’s test results may indicate that she is in the latter stages of the disease, she may still appear and act healthy.

Image Pexels stock photo

Leave a Comment