Uptick before crashing?

To varying degrees, people have compensatory mechanisms on standby for acute illness and for different stages of that illness. I like to think of it as reserve fuel tanks. When a patient gets sick, they start draining one of those tanks. When a patient is about to die they often start using any and all tanks that are left and will often suddenly appear to be oddly improving or stabilizing clinically, although usually the patient will be aware they are using their last reserve tanks (feeling of impending doom).

In Hospice, we call it "the Last Hurrah". Someone who has been lethargic, minimally responsive, little to no intake for a few days suddenly wakes up, talks a blue streak and wants to eat.

Twenty four hours later they're gone.

We prepare families for the possibility of this happening, and tell them no, mom isn't getting better, but this is a perfect opportunity to have some last quality time.

I call it getting better to die. I agree with the PP they appear better but often seem to know that they are not going to last. It is amazing for those families to have one last conversation, hug etc.