Kidney disease is a painful and debilitating disease for dogs. As a dog owner, knowing the stages of kidney disease and what to expect can prepare you to help your dog through the illness. Kidney failure most often happens with older dogs as a part of the aging process. With small dogs, kidney disease might begin at age 10 to 14. Large dogs have shorter life spans, so kidney disease often begins around age seven.
In stage one of kidney disease, dogs have toxins in their blood, but they haven't yet reached dangerous levels. Unfortunately, according to the Merck Veterinary Manual, kidney disease is rarely diagnosed in this stage because most dog owners do not have their dogs routinely blood tested for disease. It would be extremely uncommon for an owner to realize anything was wrong with his dog at this point.
In stage two, the level of toxins in a dog's blood has reached dangerous levels, but the dog still isn't showing symptoms of kidney disease. However, dogs may have increased volume of urine during this stage, but that isn't something most owners would be likely to notice.
When a dog begins showing symptoms of kidney disease, he has entered stage three. A very common symptom is increased thirst, which happens because the dog is losing more and more fluid due to frequent urination. Other early symptoms of kidney disease are fatigue, loss of appetite and depression.
Stage four is the last stage of kidney disease. A dog in this stage has advanced kidney damage and is showing extreme symptoms, like almost no appetite, diarrhea, vomiting and bad breath. Occasionally, dogs in stage four kidney disease will also have ulcers in their mouths.