What Causes Fatigue,nausea And Increased Urination While On Lithium?

My daughter has been taking lithium foe bi-polar for 20 years now. For the past 2 years she has been having the symptoms of extreme fatigue ,nausea , increased urination, thurst and severe headaches. Thes e symptoms have been in creasing in duration and frequency. She also has hair loss which started about 6 months ago. She developed a goiter on her neck about 6 months ago. It increases in size and then the fatigue and headache starts. With the nausea she has vomited a large amount of liquid a couple of times.