I’m very sorry for your loss.
It sounds like he had a hemangiosarcoma. It’s a very very very sneaky disease. My 8 y/o GSD died from a hemangiosarcoma on his right aorta. And I have 2 friends who had dogs with it on their spleen as well.
The thing about this cancer is usually the bleeding of it that kills them, not the actual cancer cells.
SHEP (my 8 y/o) was being managed very well by the holistic treatment. It was the anesthesia that he had to have to be tapped that his heart couldn’t take.
My first friend whose boxer mix had this was put down a few days after diagnosis. I think he would’ve had a better outcome if she had a better vet and/or sought out a second opinion.
My other friend’s Rhodesian Ridgeback lived for years with his. She fed him a low carb high protein diet. Mainly dehydrated raw. He had to take Pepcid. She never did the surgery because of his age.
It’s a disease more commonly found in some breeds than others. GSDs tend to have it on right aorta. Having the niece of my dog who passed I am in constant fear that she will have the same fate.
My sympathies are with you. I know how devastating it is to lose a dog. Especially so suddenly.
