DISCLAIMER: I'm not a vet and I have no veterinary or medical background whatsoever. This information on liver disease in dogs is not meant as a substitute or replacement for veterinary advice. It's meant for educational and informational purposes only, as a starting point for discussing the diagnosis and treatment of canine liver disease with a qualified vet.
You may have read stories in the news about "miracles" - someone with a major illness who wasn't expected to survive long, somehow beat the odds and was able to enjoy life for much longer than anticipated. The same goes for dogs... even highly-educated vets can only give an estimate of how much time your dog has left based on his or her experience.
The liver can be severely damaged and still continue to function. Unfortunately, this means that by the time a dog starts showing any symptoms, often times there is already significant liver damage.
In our case, I opted not to do the full range of testing. My dog, at the time of his liver disease diagnosis, was 15. I didn't want his last days to be spent attempting to recover from testing or surgery. Here are the tests we were given the option of doing.
This test is minimally invasive, and is a simple blood test. Apparently it gives an excellent indication of how well the liver is functioning, although it cannot tell you what's causing the liver problems. Basically you fast your dog for 12 hours and then draw some blood. Then you feed him a small meal, and more blood is drawn two hours later. Both the fasting and post-prandial levels of bile acids are tested.
Every lab uses different values for what's considered "normal". Our lab said normal levels are less than 10 umol/l (fasting) and less than 25 umol/l (post-prandial). When my dog was diagnosed, his levels were 118 fasting / 195 post-prandial. Three months after diagnosis, his numbers improved to 72 / 109; 5 months after diagnosis I was thrilled when the numbers came back as 3.5 / 41; and at 7 months his numbers remained stable!
This test is non-invasive. The vet used the ultrasound to get a much better picture of my dog's liver. At the time the ultrasound was done, his liver hurt a lot (I didn't know at the time) and he was given a light sedative. The results of the ultrasound showed nodules all over his liver. The vet said it looked very much like liver cancer.
With my dog's liver being as damaged as it was, he was unable to shed the effects of the sedation quickly. Even with the very light sedative he'd been given, it took him four days to return to normal, when it should have only taken a couple of hours. Seeing him feeling so miserable was what made me decide not to go any further with testing.
This test is more than minimally-invasive, due to sedation. The vet would use the ultrasound to determine where to insert a needle to withdraw some liver cells. They would do this several times so that they have a number of samples. If they're able to get good samples, then the cells could provide much more information about what could be causing the liver damage, and thus the vet can make a more informed decision about how to treat it.
On the other hand, there's a possibility that they wouldn't get any useful cells. There's also the negative that the dog has to be sedated for the procedure.
We did not do this procedure with my dog since we didn't think he'd be able to handle the sedation.
This test is invasive. The dog is put under general anesthetic and opened up. A piece of his liver is removed so that it can be biopsied. This would give the vet definite information as to the cause of the liver problems, and thus they can better determine how to treat or manage it.
We did not do this procedure.
This is obviously an invasive procedure. In some cases, the damaged or cancerous portions of the liver can be cut away.
I'm afraid that's all I know about it as my dog didn't quality for this option -- since there are nodules all over his liver there would be no way to surgically remove them all.
Obviously, the more information the vet has as to the cause of the liver problems, the better job he or she can do in suggesting treatment or management options.
In our case, we didn't know exactly what type of canine liver problems we were facing, we opted simply for "supportive care" (drugs and supplements to try to help his liver heal).
Every pet owner asks themselves the same question. It is a personal matter, as you know your dog best. One vet said to me, "Once your dog stops enjoying his favorite activites, it's time to let him go." My dog loves running (even at his very advanced age), eating, sleeping, and being involved in every aspect of my life. During the worst days of his liver disease, eating was difficult for him. Although it hurt to think about it, I had steeled myself to think about letting him go if he experienced pain we couldn't control, or if he decided he was no longer interested in running or interacting with his family and friends.
Your vet may be able to help you with insights into the "right" time to let your dog go. Ultimately, the decision is yours.
A canine liver disease prognosis can suggest that the time you have left with your dog may be coming to an end, but not necessarily right away. Regardless of how much time you have left, you can make sure you and you pup enjoy each day as it comes.