William, I'm glad you are doing better, sweetie!!  We have had a few private conversations about our mutual low blood sugar, and I, too, went to the ER about a year ago and was told it was the transient ischemic attack, although our "esteemed" (not) local hospital wasn't quite as forthcoming with the reason.  I had gone to our little local bar for a glass of wine while working on some artwork I was getting paid for...more room there to spread out than at my house undergoing renovations.  I worked for a couple of hours, had one glass of wine and all of a sudden my face literally hit the table.  Wham.  It was so instantaneous that I couldn't even gather my wits about me for a bit.  Luckily for me, the bartender was a friend of mine who is a nurse who was just moonlighting at the bar on weekends and she knew my history of the blood sugar and called my husband to take me to the hospital.  As soon as they found out I had been at a bar, they labeled me
 a drunk and blamed everything on that, even though my blood tests proved I had had ONE.  But anyway, I digress...I still get irate about that!!!  I didn't have quite the same symptoms as yours...mine was more nausea, completely weak...couldn't stand up or even keep my head up by myself, and I couldn't connect my brain to my speech.  I could THINK, but I couldn't get it out of my mouth.  It was really weird and scarey and I feel for you, I really do.  They gave me a vitamin IV, I think it might have been vitamin K, but not sure, and within the hour I was feeling totally normal again.  Bizarre and scarey.  I am assuming these attacks present themselves differently to different people??  Either way, I am very glad that you were so well-taken-care-of, and please let me know how things progress.  Maybe I need to move to Canada???  Because you really don't want to hear the REST of the horror story that I endured with these so-called medical experts
 here, sigh.  
Love,
Bren with :)'s for William

Thanks to all who responded, I appreciate your concern, especially Ron Hoggan,
who pointed me to a probable cause.

It looks like a transient ischemic attack, caused by foolish indulgence in
Christmas dinner with resultant high blood sugar. This in a person who has
always had problems with blood sugar, and has been very low to zero carb for
months.
There has already been some improvement, and the future is promising according
to medical websites.

William