I've been wondering about that too. (And btw, FYI, Schiavo's side claims Terri was bulimic, not anorexic. Bulimia apparently can cause potassium imbalance, but some doctors say potassium imbalance did not directly or indirectly cause Terri's condition.)
Larry King asked Schiavo what the malpractice accusation was about, and Schiavo claimed the "malpractice" was the alleged fact that Terri's ob/gyn didn't do bloodwork when she supposedly was having an infertility investigation.
Schiavo claimed that had the ob/gyn done bloodwork, Terri's supposed potassium imbalance would have been discovered before she collapsed.