Panic Attacks, Metallic Taste, Loss Of Appetite, Potassium And Sodium Elevates, Weakness. Post Polio Patient. Suggestion

my mom is an 88 yo post polio patient. She says she has lost taste or said she has metallic taste in her mouth. She has eaten less and less and recently became very weak and ended up in the hospital w/electrolyte problems (potassium 3.6, Sodium 120). Heart, liver, BP etc have been w/in normal ranges throughout. With IV's they got both potassium and sodium up but now she's having what seems like panic attacks (trembling inside, feels like she is going to die, etc). It does respond to Xanax. She continues to feel very bad and won't eat or drink any significant amount. We're a little concerned that it isn't panic but something else but don't know what else that could be. Any ideas or suggestions?