EPI * Exocrine Pancreatic Insufficiency

My beautiful 6 yo rescue red and white border collie, Riley, was euthanized on 2/28/09 because of escalating aggression. He was diagnosed 1.5' previously with EPI and despite receiving pancreatic enzymes and B 12 shots and seeming to have the disease under good control, ie., normal weight and stools, he began to become aggressive and nipped 3 people unprovoked, the last one he broke the skin. This was obvious aggression, not a border collie herding nip. I had worked with 2 trainers, and could not trust him at the dog park where he also began to show aggression towards other dogs and people after being a member in good standing for 4 years,  or even in our own yard when he had a 30' line on while he played ball. He had always been shy/ growly at times around strangers, but only began to nip/ bite the last 6 mo of his life. He did not appear to be in pain.

Did anyone else notice a change in their dog's personality with EPI, especially aggression with this disorder?

I am a long time dog owner, Humane Society volunteer and Delta Society therapy people/ animal trainer, but I was not prepared for this heartache.