My tripod, Lamar, is about 2 years old and had his back left leg amputated when he was a very small kitten (he was found with a badly broken leg that couldn't be fixed). He's absolutely fabulous. He can run around and wrestle with my other cats, climbs all over the place, and has been generally in great health. He's an indoor cat, but we have an outdoor enclosure where they can get outside time and still be safe. 

He had three weird episodes recently. One I wasn't home for, but my husband told me that Lamar was suddenly screaming like he was in terrible pain, but it only lasted a few seconds and he was back to normal. The second one, Lamar was asleep and did the same thing. Howling like crazy and kind of scootching around not able to use his remaining back leg. But it only lasted maybe 5-10 seconds (seemed much longer of course). 

Today, he came flying up the stairs from the basement, howling and screaming... went under the couch... ran out and flopped over, still howling, not really able to move his back leg. This episode lasted much longer. Maybe almost a minute or so. My husband and I brought him to the local emergency vet. They gave him some pain medication and did an xray and blood test. Nothing seemed out of place. The doctor checked out his back leg thoroughly and said it seemed fine and thought maybe he might have pulled or twisted something. We were sent home with pain medication and told to keep him resting. They said they would recommend an MRI or CT scan (or both... I forget) if he doesn't seem to be back to normal.

We put him in a spare bedroom that doesn't have any furniture in it so he won't try to jump on/off anything. I put some favorite comfy stuff and a litter box in there. Gave him some food that he scarfed down. I went in to check on him and he was hopping around like normal, purring like crazy and seemed alert and great. Then all of a sudden, he kind of did the crazy screaming howl and flopped over again like his leg wasn't working. Just for a quick second.

I thought maybe I got him a little too riled up with petting, so I left the room and he quieted down. He's in the back room now and all is still quiet. I think he's sleeping and will peek in a little later, but I don't want him to wake up and get all excited again. I'm hoping the pain medication will do the trick so he gets some good rest.

I left a message for my usual vet, so I will probably talk to him first thing in the morning. I'm just wondering if anybody here has had anything similar happen. Or has anyone had a rear-leg amputee strain their remaining leg and if so, did their cat have this kind of reaction. It seems weird that a tear/twist would cause the three worsening episodes. I was thinking maybe he injured himself a little the first time and maybe it got worse with activity? Or maybe he had slightly hurt himself jumping off something and then did the same thing that originally caused the injury and it got worse? My husband also was wondering if maybe it was some kind of crazy cramp in his remaining leg. 

On sort of a related side note, one of my other cats, Buddy, did something to one of his back legs and was limping a little bit recently too. I have no idea how that could have anything to do with Lamar's issue, but figured I'd mention it. 

Any information would be greatly appreciated.