AEIOU TIPS. This is easily one of the most important mnemonics of emergency medicine because it represents the differential diagnosis for altered mental status. Obviously, this is not meant to be an exhaustive list, but it certainly provides a good framework to start with. Even as a resident, I still will write out this differential when I’m placing orders on a complicated, altered mental status patient. It keeps me from missing something obvious, and it’s crucial for your training as a medical student.