Kidney failure is defined as
the inability of the kidneys to remove waste products from the blood. The
buildup of toxins produces the signs and symptoms of uremic poisoning. Kidney failure can
appear suddenly (acute kidney failure) or come on gradually over months. Most
cases are of the gradual onset type and are caused by nephritis and
As they age, our dogs often suffer a decline in functioning. Their memory, their ability to learn, their awareness and their senses of sight and hearing can all deteriorate. This deterioration can cause disturbances in their sleep-wake cycles, making them restless at night but sleepy during the day. It can increase their activity level (resulting, for example, in staring at objects, wandering aimlessly or vocalizing more) or decrease their activity level (leading to less self-care and poor appetite)...
Dogs with kidney failure do not show signs of uremia until 75 percent of
functioning kidney tissue is destroyed. Thus, a considerable amount of damage
occurs before the signs are noticed.
Signs of Kidney Failure
One of the first things you may notice is that your dog drinks and urinates more than usual and indicates
her need to go outside to eliminate several times a day. If not allowed to do
so, the dog may begin to have housetraining accidents in the house. These signs
are due to the failure of the kidneys to concentrate the urine. This results in
a large urine output over which the dog has no control, with subsequent dehydration and thirst.
As kidney function declines, the dog retains ammonia, nitrogen, acids, and
other chemical wastes in her blood and tissues. This is called uremia. The
degree of uremia is determined by measuring serum blood urea nitrogen (BUN),
creatinine, and electrolytes.
Signs of uremia are apathy and depression, loss of appetite and weight, a
dry haircoat, a brownish discoloration to the surface of the tongue, and an
ammonialike odor to the breath. Dogs at this stage may urinate less than
normal. Ulcers may arise in the mouth. With the nephrotic
syndrome the dog develops ascites and edema. Vomiting, diarrhea, and gastrointestinal
bleeding may occur. At the end stages of kidney failure, the dog falls into a
Treating Kidney Failure
Dogs with kidney failure require periodic monitoring of blood chemistries to
detect changes in kidney function that may require medical intervention. A most
important step is to restrict salt intake. This helps prevent edema, ascites,
Protein is poorly metabolized by dogs with kidney failure, but what to do
about protein levels in the diet is currently an area of controversy. Some
veterinarians believe a diet rich in meat, or one that contains poor-quality
protein, creates an increased nitrogen load that must be handled by the liver
and kidneys. Dogs with weak kidneys can be thrown into uremia by feeding them
more protein than they can handle. Other veterinarians believe that as long as
the protein is of high biological value, it will help the kidneys retain their
function. Diet may need to be customized to the individual dog.