Kim, first my sympathies for your tremendous loss. I've been through a roller-coaster ride with my little girl--also kidney problems. Our problem was a build up to toxic levels from a prescribed medication. So our problems were related to a poisoning and she was able to pull through, but it was a very rough time.
Please understand I am not an animal medical professional. From my research I found out there are two types of kidney failure: Chronic renal failure and Acute renal failure. We dealt with Acute failure which is typically brought about quickly via poisoning or an accident. With proper, prompt treatment acute renal failure can be reversed and there may or may not be long-term kidney damage. Chronic failure is something that occurs over a long period of time. It can also occur when the renal system is malformed due to a birth defect. Both acute and chronic are incredibly dangerous.
Typically chronic renal failure is only diagnosed once the kidneys are functioning at less than 75%. By this time the animal is quite sick and supportive, life-extending care is the only treatment. This can include administering subcutaneous fluids to prevent dehydration. What happens is that the kidneys aren't working to eliminate toxins. As the toxins build, the dog tries to drink more and more to help flush the toxins from the body. At a certain point, the dog cannot drink enough--that is when the fluids are administered. Special diets can be prescribed to help diminish the level of toxins produced. Unfortunately, there is no way to repair the damage to the kidneys in chronic renal failure.
In our case, my dog was prescribed a medication that was processed in the liver. In her case, her liver was compromised from abnormal high liver enzymes and hepatitis. This probably lead to the toxic buildup in her kidneys. Within a few days, she got very, very bad. She had some bloody, loose stools, bloody vomiting, complete loss of appetite. I was in constant communication with my vet and was able to get her hospitalized. Her Creatinine level was at 7. After nearly 2 weeks in ICU, the level dropped to 1.7 and she was discharged. We are still in a monitoring phase to determine what level of permanent damage was done. If she has permanent damage, then we will be at a chronic renal failure stage.
My heart goes out to you. Unless there was an obvious poisoning event or a traumatic accident, it is likely that your dog had chronic renal failure and there would have been very little that could be done to help once diagnosed. You might have been able to have done IV rehydration and then sub-Q fluids, but at a certain state, your dog would have had a very limited quality of life. Please don't beat yourself up. I watched my baby go downhill for 3 days while we were treating her for a suspected stomach ulcer--the common side effect from the medication--but it ended up being renal failure. I didn't know either. Your dog was sick--you got him medical care. I am sorry.
