My horse had a seizure....
..and I don't know what to do.
He's been off work essentially since May, when he was diagnosed with navicular problems. (Before that we did training level eventing.) We've tried a plethora of shoeing and medication options, none of which so far have helped. He's been off all medicine for several months, except for a small dose of Thyro-L which he's been on for years, because of his metabolic issues (never quite defined, but, like porn, you know it when you see it).
Today I brought him in for the farrier at 9. He was shod around noon--I was there for the front feet, he was standing easy and looked great. Then I had to go back to the house (it was raining in my basement; a whole nother story); when I returned, my farrier said that Gully had stood calmly for all four feet. Then he put Gully back in his stall, and as he removed Gully's halter Gully went stiff, threw his head up, and began to lurch uncontrollably around the stall. The farrier couldn't get to the regular door, so went out over the dutch door to the pasture to get out of the way. Gully collapsed against the water buckets, completely crushing one, fell to the floor, and lay shaking for about 40 seconds.
Then he slowly regained his feet. By the time I got back to the barn, maybe 15 minutes after this happened, he looked fine. I went in and stroked him, and he seemed fine. Later when I put his grazing muzzle on before turning him out, he got a bit stiff, with an odd look in his eye, but then he walked out of the stall as normal.
What the heck? Can anybody help me here? He's turning 16, not overweight, on full turnout, a Connemara if that helps.