Chronic kidney disease is a problem that is seen commonly in middle-aged to geriatric cats, and less so in older dogs. It is to be differentiated from acute kidney disease by the amount of time of onset and by treatment. Chronic kidney disease cannot be cured, only managed over time. Acute kidney disease, if caught early enough, can be cured. I will discuss acute kidney disease in another article in the future.
The definition of chronic kidney disease (CKD) is the following: an abnormality of kidney structure or function existing for more than 3 months. There are 4 stages for CKD that can be defined according to changes in the blood work that is used to diagnose the problem. It is recognized when certain changes in blood results are seen, called azotemia. Also, the animal’s ability to concentrate urine is lowered. There may be no clinical signs when it is first diagnosed. The cat or dog may look totally normal. Other pets may be sick, and require treatments or hospitalization at the time of diagnosis.
There are several outward signs of CKD which may be seen. Drinking more water and urinating more often are usually the first symptoms. Decreased appetite and weight loss can also be seen. When the animal is feeling more ill, lethargy, vomiting, bad breath, and stupor may be observed. These latter signs mean the pet is in a decompensated state and needs therapy soon.
What are the causes of chronic kidney disease? Sometimes certain breeds of cats and dogs have an inherited kidney problem that they are born with. The majority of cases involve an inflammation of the inner structures of the kidney that develops over time, where it comes from is usually unknown. Other causes can be acute kidney disease damage that leads to a chronic condition, certain types of cancer, kidney stones, and other rarer diseases such as polycystic kidney disease and bacterial kidney infection.
What can be done to treat the poor animal with CKD? Acute treatment may be required depending on the stage of the disease at the time of diagnosis. This involves fluid therapy of varying types. If the pet is ill, IV fluids are a staple of treatment. If the finding is incidental, and there are no signs of illness, subcutaneous fluids may be administered. A change of diet to a specialized kidney diet is essential as well. This lowers the aforementioned azotemia in the blood, lessening the kidney workload. Using medications for control of nausea or vomiting may be initially indicated as well.
There are many other potential treatments for the management of the disease as well, depending on the stage of CKD, and the changes that occur in the body due to the malfunction of those organs. Secondary changes can be the following: dehydration, anemia, lack of potassium, lack of calcium, more calcium, extra cholesterol, protein loss, increased blood pressure, and withering or enlarging (depending on the disease cause) of the organs themselves. Most of these problems, once identified, can be managed. It mostly depends on finances, and the ability to actually medicate the animal. This can be difficult with many cats!
What is the prognosis of this disease? This depends on at what stage of the disease is determined at the time of diagnosis. It is usually difficult to predict in an individual patient but there are documented survival times for cats. With stage 2 CKD, a cat successfully managed can survive up to 3 years. A stage 3 cat can survive up to 2 years. Stage 4 CKD (which is the end stage); cats only survive approximately 1 month. The survival times in dogs are highly variable, again according to the stage, the root cause of the CKD, and the ability to manage the symptoms.
In short, the treatments for CKD are aimed at improving the quality of life and delaying the progression of the disease for both the cat and dog. Expectations of cost and inconvenience need to be considered in the management of this problem. I hope this article didn’t depress you! If you think your pet is drinking more water and urinating more frequently, there are other less dire causes for this other than CKD. The cause needs to be determined first! But if you suspect CKD in your furry friend, or have any questions for us, please give us a call or ask about it at your next appointment. We appreciate all of you and your wonderful animals.
Dr. Jaime Kozelka
St. Francis Hospital for Animals