Eric Needs More Purrs Please .

Eric has taken a turn for the worse. The last couple of weeks he has been eating well and been quite lively. On Saturday he started to stumble sideways and was still doing it this morning so we took him to the on call vet. There is no sign of middle ear infection.
There are two possibilites, one being arthritis in the hips which is causing him to stumble. He has had a painkilling injection of metacam and we will inject him again Monday and Tuesday. This is mainly because  the possibility of it being arthritis is the easier to eliminate. If there is no difference it probably is not that. The other far worse possibility is a blood clot. It is possible that a tiny piece of the clot broke off and that is why the end of his tail has drooped. His blood pressure is high, but not yet dangerously so. The 30 minute journey to the vet could well have raised it, but not as high as it is. One of the vet nurses keeps her horse with us and is going to take his blood pressure here at home on Tuesday to see if there is any difference. If it is still high he will go on tablets to try and bring it down. The thing that scares us most is if it is a clot and a larger piece breaks away it could cause a saddle thrombus.
We are very worried for our boy. Please keep him in your purrs and prayers.