Help with Case Study!

So I'm in my first day of geriatric class and we are required to give responses to case studies weekly. I put the scenario below for everyone to read, I would really appreciate any feedback! I have some theories about medication interaction and electrolyte imbalances but I would sure appreciate being reassured with other ideas!

You are caring for a 78 year old female patient diagnosed with CAP (community acquired pneumonia). She was admitted to the hospital from home where she lives with her daughter. Currently her vital signs have been stable and she has no fever. She is being treated with IV antibiotics for her pneumonia. Other medications include; Digoxin, Lasix, Lopressor and Tylenol for fever. During your initial assessment at 3:00PM she was alert and oriented x3. When you enter her room at 7:30PM she is confused, agitated and asking for her husband who has been dead for ten years. What could possibly be wrong with her?