i took my dog to the vet sunday for a rash on his head. he was started on prednisone and amoxicillin. on wednesday, we were all sitting outside and he was running around playing. his head was healing nicely. he ran about 30 feet, turned around and ran back to my son. he stopped and walked a couple of steps to get his ball which was under my son's foot. he turned and stumbled a couple of steps and hit his head on the cement. stood back up, walked a couple of steps, rolled onto the ground, tried to get back up, and just flopped down onto his belly with his head hyper-turned to the right side and died. he was only 4 years old and, other than the skin rash which the vet said was a common rash she has seen several times this year and it was almost healed, he appeared to be in perfect health. what could have happened to him?