Things are going from bad to worse. She seemed a little better during the night, when she realised I was with her, she got up to come for a stroke, and seemed a bit more alert. She even pulled the quilt off so she could lay on it.
However, her temperature is even higher, and they've kept her in to do an ultrasound and chest X-rays. I've asked that, if it's possible, they can do the X-rays under sedation, rather than full anesthetic.
So we just wait and worry till they ring later, when we can hopefully bring her home, and have some idea of what's wrong.