Reply #11: Possibly a systemic infection from a dental abscess?

[Tanuki]

http://www.nlm.nih.gov/medlineplus/ency/article/001060.htm
Some people with prolapsed a mitral valve have to take antibiotics when they have even routine dental cleaning, to avoid bacterial endocarditis, which can set up a secondary brain infection. Don't know if this has anything to do with Falk's situation, however. Other possibilities could be anoxia during surgery of any kind, or reaction to the anesthesia. Sometimes people who have vulnerable brains (e.g., early Alzheimer's, before anyone really noticed there was a problem) look much worse when recovering from anesthesia, and people erroneously blame the surgery, even though the process was already well under way.