Can't stand on one leg , then being sick

by Karen

My baby grey had sore leg ,took him tonthe vets. Vet xrayed him and said he had inflammation ,gave him antiflammitory drugs and said he would be ok . But he got worse and was sick ,took him back but the vet said he was ok. My baby was only 4 months old and he died 12 hours later. What could have caused this please.