A Sneaky Beast

by Christopher Forsythe, DVM

Harley the cat has a human who is one of the coolest clients I have: smart, funny, and just sassy enough to keep me on my toes. Oh, and did I say how much this client adores her pet? Anita’s love for her cats is nearly out of control. It eclipses almost everything else in life including money, material goods, travel, chocolate and, I suspect, even a superb martini. I would go so far as to say this woman reveres her cats so much she would be eager to see one of them take over the Oval Office.

“I think she’s losing weight,” she announced to me a few months ago on her way into my exam room with her cat Harley draped over her shoulder. They were here for the annual exam, so she said “You’d better find out what’s going on. And I want it to be good news. Please, Dr. Chris, make it be good news!”

Harley’s physical exam revealed some important findings. She had lost some weight, half a pound to be exact. But on a 10-pound cat, that amounts to five percent of her body weight, and that’s nothing to sneer at. Plus she was somewhat dehydrated, evidenced by the fact that I could pull up her scruff, and it tended to stay tented up rather than bounce back the way it should on a well-hydrated cat. As I felt along her flanks, it was obvious her kidneys felt a little smaller than normal, and that was the clincher. I knew that this savvy pet worshiper, my soul sister, was right. While I finished the physical exam, the spectacular brown tabby turned her cherubic head around and gave me that special squint, that look that said to me “get to work, you twit.”

What is chronic renal failure?

Chronic Renal Failure (CRF) is elevated levels of urea or other nitrogen-containing compounds in the blood (azotemia) combined with diluted, watery urine, usually caused by the failure of the kidney to get rid of these toxins. Plus the condition has lasted from months to years. An interesting aspect of the disease is that the dog or cat has to lose about 75 percent of his functional kidney mass before the problems really begin to show up clinically or on a blood or urine test. As the kidneys lose their function over time and can no longer do their ever important job of concentrating urine to eliminate waste, pets show increased signs of drinking and urinating. Azotemia occurs as the liver breaks down the proteins in the food ingested and metabolized into blood urea nitrogen (BUN). The kidneys, with their poorly functioning nephrons, cannot keep up with the workload and don’t filter these toxins out of the body, so they are left floating in the bloodstream, leading to advanced disease.

Who, why, what?

Dogs and cats both get kidney failure, but we see about twice as many cases of CRF in cats than dogs. Some purebred animals with a higher incidence of the disease include Basenji, Beagle, Bull Terrier, Cairn Terrier, Chow Chow, Doberman, Cocker Spaniel, German Shepherd, Golden Retriever, Lhasa, Mini Schnauzer, Rottweiler, Samoyed, Chinese Shar Pei, Shih Tzu, Soft-Coated Wheaten, Standard Poodle, and Abyssinian cats. The average age at diagnosis is about seven years in dogs and about nine years in cats, but as pets age we see even more frequent cases.

Most cases are idiopathic, which means we don’t know the exact reason why that pet’s kidneys began to fail. But it isn’t too hard to recognize the warning signs. Pets will drink more and urinate more frequently too since what goes in still needs to come out. Dogs and cats will become anorexic, lethargic, lose weight, and vomit. Other signs can include constipation or diarrhea and even acute blindness secondary to increased blood pressure. Cats may begin to slobber, show muscle weakness, and flex their necks down from the low potassium in their bodies and its effects on their muscles. Some of these poor kitties look like contortionists at the circus, but it’s certainly not entertainment; the poor babies are struggling to control their bodies.

Don’t dilly dally

Since the effects are profound, and the prognosis depends often on how early the condition is diagnosed, it is important to get to the veterinarian early for diagnosis and treatment. With all that fur covering their bodies, and especially with aloof cats who may only grace you with their presence a few short minutes a day, it is key to check your pets to see that they are in good flesh, drinking a normal amount of water, and not appearing to be dehydrated or losing weight. If they are, you need to have them examined.

The vet may notice small, irregular kidneys, and/or dehydration. The doctor will also look for “wasting disease” on physical exam as well as pallor to the mucous membranes and oral ulcers. Breath that smells like kidney toxins is also noticeable on physical exam and must be distinguished from the foul odor of dental tartar. Finally, the doctor will want to check your pet’s retinas for changes in the blood vessels that may indicate increased blood pressure or other problems.

Blood tests for azotemia (high BUN and creatinine), elevated phosphorous, and a low urine specific gravity (very dilute urine) will confirm the diagnosis, and your veterinarian may want to further pinpoint the severity of the disease by using some other diagnostics:

• Abdominal x-rays may demonstrate small kidneys or misshapen kidneys that are poorly functioning.
• Abdominal ultrasound uses a transducer and sound waves to give clear images of the kidneys and detail the architecture of the kidneys potentially to identify the underlying cause of CRF.
• Blood pressure reading: this is helpful in determining if a pet has hypertension.

Once the disease is confirmed the veterinarian can recommend therapy and treatment to improve your pet’s condition and attempt to keep the progression of the disease at a minimum.

Treat me, treat me, I love treats!

Patients with chronic kidney disease can benefit from many treatments designed to slow disease progression. CRF tends to progress to terminal chronic renal failure over months to years, so treatments that can slow this progression are vital. Among the treatments your veterinarian may want to use are:

• Switching your pet to a diet low in protein, phosphorus, and sodium. With less protein to digest by the liver, there is less BUN created and less workload for the kidneys, and less toxins left over floating around in the blood making your pet feel sick.
• Keeping your pet well hydrated. If your pet is in a uremic crisis (very sick when presented to the veterinarian) then hospitalization will most likely be necessary to allow IV administration of large amounts of fluids. Once he is discharged, subcutaneous fluids can be administered daily or every other day either at home by the owner or at a veterinarian’s office with great benefit to your pet.

Your vet can also give erythropoietin injections when a pet has developed anemia secondary to the renal failure. Erythropoietin is effective in “waking up” the pet’s bone marrow and jump starting it to produce more red blood cells to combat anemia that often accompanies CRF.

Epikitin, a phosphorus binder, absorbs the extra mineral from your pet’s body so it won’t tax the body. This is a powder that can be sprinkled on food daily.

ACE inhibitors are medications that essentially dilate the arterial blood vessels in the body and help to reduce hypertension.

Your veterinarian has all the above medications and more. Since pet owners have come to expect only the best for our “family members” even kidney disease no longer causes us to let our pets just lay down and die in the corner. We can provide many useful medications and therapies to prolong a good quality life and keep them healthy and active in most cases for quite a long time.

Happy, “healthy” Harley

Harley had very high BUN and Creatinine on her blood test, as well as elevated phosphorus and slight anemia. X-rays confirmed that her kidneys were about 15 percent smaller than they should have been, but other tests showed no signs of cancer or other problems whatsoever. Her blood pressure was normal, and her treatments, which are included in the list above, stabilized her and put her into a holding pattern with her kidney disease in check for now. Naturally her owner is relieved and happy that her companion is doing well, and Harley is just glad that her “twitty” vet was able to handle the renal situation so she could concentrate on her favorite hobby, bird watching.