Let me start by saying that we are deeply saddened that our 10 yr old sheltie passed yesterday, with the advise of our vet we decided to put him downn, and I am simply looking for a more definitive reason. 2 yrs ago he was diagnosed with an autoimmune disorder and hypothyroid. He was placed on long term steroid therapy and thyroid meds, which he seemed to immediately respond, including dropping about 10lbs. Within the last several weeks has at time become disoriented, aggressive, and within the last two weeks at times having difficulty getting up on his own and during these times when he does get to his feet it's almost like he doesn't know where he is, ie. ask him if he wants to go bye-bye and he goes into the kitchen, instead of his normal jumping at the front door. At the onset a few weeks ago, the vet gave him a steroid shot and after blood work revealed high white blood cells placed him on antibiotics. Again he seemed to respond fairly quickly. This time around, another steroid shot and they began treatment for some type of muscle disease, which they gave me the name, but unfortunately I don't remember. Another blood panel revealed that his white blood cell count had increased significantly. The vet also told us that he had started seizing, 2 to 4 times per day. The first day we went to see him, he would raise his head and attempt to get up to be with us, but would put his head down and seem to fall asleep. The second day he would do the same, although when he would put his head down he would just lay there with his eyes open. Yesterday, his eyes would just move rapidly, with an occasional few leg kicks, however he could not even attempt to pick up his head. The vet advised us that there was some type of brain or central nervous system issues going on with him, possibly a brain tumor or meningitis. In looking over some of the symptoms of brain tumors and thinking of the past 6 months I too wonder. We took him to the vet about 6 months ago for aggressive behavior, including biting at me for tugging on his collar near the back of his head. He had difficutly finding a comfortable place to sleep at night, often walking around with excessive panting, and leaving the bed to sleep on the floor. We noticed that he began sleeping on the cold tile near the front door instead of his normal place right next to me on the couch.