I have pulled a few 24 and 48 hour "days" and never reached that gitty stage myself. Usuallly, I just get cranky and start snapping like a starving Pit Bull.
As far as my own situation with lack of sleep- I ask for help and people tend to either laugh, not follow through, or just don't perform. A close friend of my encouraged me to ask for help years ago and I started, aside from him and a couple other people it helped, then life turned terribly bad and I looked about and found that most of my friends (about 90%) were fair weather friends. So now- I offer help, I don't ask, if you feel like helping me then okay, but seldom will I accept.
Thanks for the kindness.