i'm sorry that i don't know but i do know how in tune you are with your cats,like myself,i watch them constantly when i can and almost analize them if i see anything that isn't normal to that individual cat.
my husband doesn't see the things that i do...then later finding i was right he knows how in tune i am with them like you.
to me...it would of scared me also,seeing the tremor...i feel so bad that your kitty mat have this.
i usually to put lysine in all the cans of catfood that i open.it's great that you do that.
maybe it isn't CH but it could be a mild start of it...just keep an eye out and try not to worry to much.

hoping your doing great otherwise Laura