My mom has been having screaming episodes from anxiety?

Evaluation? Have you considered taking her to be evaluated? Too much info is missing from the question. How old is your mom? Are these symptoms new? Does she have any medical diagnosis? In any case, if her behavior is something different, then the evaluation by her primary care doctor is warranted. If behavior deteriorates where it's not controllable, you can take her to the er where she'll be evaluated.
Needs to be seen. This is never appropriate behavior, and one should not be trapped in emotions that trigger this. Your mom needs to be seen by a physican; if she is reluctant to be seen, the family may need to make an "intervention", sticking together and laying out options. A person who has this is unemployable and will lose their social support. I'm told that medication, talking, and adjusting situations help.