I gave the chis their heartworm meds and also treated them with k-9 advantix which they get every month. When I came home today, Bruiser was obviously having major neurological issues. He couldn't walk without stumbling, appeared to be blind...bumping into things...just was very off. Took him to vet and he has been admitted. They are not sure what is causing this but most likely the k-9 advantix. Don't know if the blindness is going to be permanent or not....I am heartbroken. Any body hear of any of these issues before? I am praying he is going to be ok.