It's actually called Head Tilt. It's not usually fatal and they can live the rest of their life with it. It's usually caused by an inner ear infection. If you want, take her to the vet and see if it is indeed an ear infection. If so, the vet can prescribe ear drops to use for 1-2 weeks non-stop. It shouldn't be expensive. They're only ear drops for pete's sake. He will give you the ear drops only if the eardrum is intact. If it's not, then she will live with her world tilted.