Feline Kidney disease; a common problem that even more commonly goes unnoticed.
Hey Doc, my cat is drinking a ton of water and the clumps in the litter box are huge. It seems like my cat is losing a little bit of weight, maybe eating less, what do you think could be going on? The first thing I think of as a doctor is “ could this cat be suffering from kidney disease????
As young veterinarians, we were taught that “cat’s don’t read the book” This may seem a strange statement, but absolutely true. Most animal species inherently hide their disease until it reaches a pivotal point. None more so than our feline friends. One of the most common problems that we see is kidney disease and again cats don’t read that book to tell us that there is a big problem under the surface until often times it is critical and life-threatening.
What exactly does the kidney do?
The kidney has several major functions, namely, conserve water, filter out waste products and maintaining electrolyte balance. The kidney is composed of millions of units called nephrons. These little units are the gatekeepers of what stays in and goes out of our body.
So just what happens in the kidney?
- Water conservation: Hydration of the body depends not only on water consumed but on water removed. In times of dehydration, the kidney must respond by conserving water. Similarly, if you drink too much water, the kidney needs to efficiently remove the excess to prevent dilution of the bloodstream. A pet with insufficient kidney function will not be able to make a concentrated urine and will need to drink extra water to process the body’s waste chemicals. For this reason, excessive water consumption is an important early warning sign and should always be investigated. We measure this urine concentration by something called urine specific gravity. The higher the number, the more concentrated it is, the lower the number, the more dilute
- Toxin removal: The kidneys are responsible for removing metabolic waste from the body. If the waste builds up due to a lack of function, we can see certain changes in the bloodwork. SDMA, BUN and Creatinine all increase when the kidneys are unable to perform the job of filtering waste. This is called azotemia, or elevated renal wastes in the blood. Uremia is the name for the clinical signs our pets feel when the azotemia reaches a certain point. Uremia makes a pet feel nauseous, they don’t want to eat, they are very lethargic and often very dehydrated.
- Maintaining electrolyte balance: The kidney plays a major role in controlling electrolyte balance, in particular, calcium and phosphorous regulation as well as conservation of potassium. Unregulated calcium and phosphorous leads to weakening of the bones. Also, insufficient kidneys lose their ability to conserve potassium, this leads to weakness. Supplementation of potassium and phosphate binders, preventing the accumulation of phosphates are often key in treating kidney disease.
These are just a few of the important things kidneys are responsible for. They also maintain the pH balance of the blood, support red blood cell production by sending signals to the bone marrow and conserve vital proteins important for the day to day function of the body.
Why do cats get kidney disease?
Feline kidneys work very hard for many years. They are able to conserve water incredibly well, given the desert origin of cats. Over time, the kidneys just basically get tired. There are many causes of feline kidney disease. Some unchangeable, like old age, especially greater than 9 years of age, certain breeds and other risk factors. Some of these factors can be tested for and treated by a veterinarian:
- Pyelonephritis (kidney infection)
- Nephrolithiasis (kidney stones)
- Ureteral obstruction (stones causing a blockage)
- Tubulointerstitial disease (disease of the kidney tubules and surrounding tissue)
- Glomerulonephritis (disease of the kidney’s filtering unit, glomerulus)
- Feline infectious peritonitis (FIP)
- Amyloidosis (typically a genetic problem seen in Abyssinian)
- Siamese, Oriental breeds
- Polycystic kidney disease (genetic disease is seen particularly in Persian cats)
How can I tell if my cat has kidney disease?
Although cats are masters at hiding illness, there are some signs that you can see that may indicate that your feline friend may be having issues with their kidneys.
- Subtle weight loss
- Some increase in urine production and water consumption
- Decreased appetite
- Weight loss
- Increased urination and thirst
- You will likely notice your cat sleeping more, grooming less and appearing unkempt. Your kitty’s gums may not be as pink as usual indicating anemia, a problem with advanced kidney disease. In more severe cases, you might notice an unusual bad breath associated with oral ulcers.
The International Renal Interest Society has developed staging criteria for pets with renal disease. Stage I is no clinical signs but evidence of disease based on laboratory findings, up to stage IV where pets actually are sick with their kidney disease.
So now I know my cat has kidney disease, why do I do?
Although there is no definitive cure for chronic kidney disease, treatment can improve and prolong the lives of cats with this disease. Therapy is geared toward minimizing the buildup of toxic waste products in the bloodstream and slowing the progression of kidney disease.
- Dietary modification
- Controlling hypertension (high blood pressure often associated with kidney disease)
- Decreasing urinary protein loss
- Addressing anemia
These treatments often include possible IV fluids administered in the hospital to decrease toxins until your pet feels better, followed by other therapies such as phosphate binders, potassium supplementation, and administration of fluids subcutaneously, have the potential to help cats with chronic kidney disease.
What can I expect after my cat has been diagnosed?
Some cats respond very well to treatment while others do not, so the prognosis is variable. The earlier chronic kidney disease is diagnosed and treatment is initiated, the better the outcome. It is important that you have your older feline friend screened regularly for blood work to catch changes even though there are no symptoms. If your feline pal is showing ANY signs associated with kidney disease, get them in to see their vet and have a full physical exam and diagnostics tests run, Getting treatment early can possibly add much more quality time with your feline friend.
I am always happy to answer any questions, on any topic about your fur babies. You can contact me at firstname.lastname@example.org, call 318-797-5522, or stop by University Veterinary Hospital and ask for Dr. Alisha Spivey.