We estimate that Riley had 5-6 seizures. They were silent, but he would lose bladder control. If we didn't witness them, we knew they had happened when his bed was wet. We checked and changed his bedding all day/night, and tried to be nearby to be with him. The strangest thing was, his mood seemed BETTER than usual during this 48-hour seizure fest. I have a theory about that.... A seizure is uncontrolled electrical activity in the brain. So is ECT (electroconvulsive therapy), which is still used on patients with intractable depression. (Nothing like what you saw in Cuckoo's Nest, promise.) So it's possible that Riley was giving himself ECT with these seizures and actually lifting his mood and easing his fear with that electrical reset.
On Sunday night the seizures stopped. Riley has since struggled to get out of bed and hasn't been interested in going outside. We've resumed the outside routine from when he first arrived five years ago - on a leash and out the front door, which bypasses the stairs and dog door. We're thinking this is just a little easier for him. He has some weakness in his back legs and is slow to get started. In the morning I've been using a towel as a sling to lift him onto his feet, and once he's off the slippery kitchen floor he doesn't need assistance anymore.
He's eating, drinking, watching us, alert when we are in the room with him, making nice poops (Not too much information when it's one of the few indicators you have about internal organ health!) and generally back to being himself. We have no idea why he seems fine now.