cat died; renal failure; green/yellow vomit?

Question
Our cat was 7 years old, and just died last night about a month after being diagnosed with renal failure.  I didn't know it could happen to a cat this young, and it has been very painful, sad, and heart wrenching to watch, and not know when we should give up and euthanize him.  This being my first cat, I didn't know how to handle it. We had been treating him with subcutaneous fluids, but he had stopped drinking water and eating, for about 10-12 days at this point, and had been bleeding from the mouth for several days.  The vet said this was due to the toxic build up in his blood since the kidneys were no longer working, and sores form in the mouth.  I was trying to get home from work in time to take him to the vet and release him from the pain but I didn't make it in time.  His last moments were very strange though and made me think an organ ruptured.  He let out a very low, very long, guttural moan, and began vomiting greenish/yellowish.  About 6-8 minutes later he was gone.  What could this possibly have been?

Answer
Hi Sean.  I'm sorry you had to experience that.  To be very honest, I think you just witnessed a typical natural death, which is rarely as peaceful as we hope it will be.  A kidney patient's passing is especially lengthy and difficult to watch.  Every body process shuts down, one by one.  There are often neurological aspects due to both the toxins in the blood and the lack of oxygen to the brain because of severe anemia, which may have had something to do with the strange noises he made.  Convulsions are common in dying kidney patients which also can account for some strange vocalizations.  The emptying of stomach contents is a common occurrence during the dying process.  The stomach sphincters relax as the body begins to shut down, allowing stomach contents to escape.  Cats who have eaten anything recently will usually lose their bowels as well.  

I don't suspect that anything particular happened in this case, except that your kitty's body finally shut down.  While we like to think that means they're peacefully slipping away, it's really a brutal and disturbing process to witness.  It's nothing like what we see when someone dies on TV.  Thankfully we are able to act compassionately with euthanasia, but knowing exactly when to employ it is often difficult.  I think that remains the most difficult part of pet ownership.

My thoughts go out to you and your family.

Jessica