This article is from the Canine Medical Information FAQ, by Cindy Tittle Moore with numerous contributions by others.
Acute kidney failure, or kidney failure, is sudden and extreme and
requires urgent care. Usually the dog recovers completely if it
survives at all.
Chronic kidney failure, or kidney disease, is common in old dogs. The
kidneys slowly wear out over a long time. It can be diagnosed by a
blood test or urinalysis. Early signs include drinking and urinating
more, since the kidneys need extra water, and foamy urine is sometimes
Treatment is mostly dietary. They need a very low protein diet that is
also low in certain minerals. The kidneys are stressed by too much
protein and will wear out more slowly on a low protein diet. Dogs with
sick kidneys should be given all the water they will drink.
The best known kidney diet is Hills K/D, but there is also Hi-Tor
Neodiet, Neura Kidney Diet, and others. Some "senior dog food" is low
in protein as well, but not as low as the kidney foods.
If you have any reason to suspect it, have the dog checked by a vet.
Many old-dog kidney cases live happily for years with no special care
other than the food.