Ongoing mystery condition... (Long)

First of all, I thank anyone who reads this, because my 2 vets and I are sort of lost. I am hoping that someone may have dealt with this bizarre condition and may have some answers. Sam is a 9.5 year old neutered Pit Bull. he is 97 pounds. No underlying medical problems until now. His symptoms began in November 2020. A timeline of episodes will follow below. Sam's first episode was out of the clear blue. He began involuntary muscle tremors, mostly in his back legs and abdominal area. He was seen promptly by his primary Vet. Imaging showed spinal arthritis, and a blood panel looked good, but showed a low/normal Thyroid. Sam's symptoms subsided in approximately 2 hours with no treatment/medication. By the time the office opened and he was seen, he was back to normal. Vet began Sam on 90lb dose of Meloxicam and biweekly PT and Chiropractic treatment. His mobility improved. February 2021: The exact episode occurred. He was seen again, and based on the thyroid level, we did more extensive Thyroid testing as well as a Cushing's Disease test. Mostly because of his minor hair loss, weight gain and lack of energy/enthusiasm for life. Cushing's was negative. We did begin treatment for Hypothyroidism. (We do not think that's a part od the episodes, but wanted to rule out CD due to the strange symptoms.) July 2021: Another episode occurs, more minor than the first 2. He was not seen, but we spoke to the vet and continued regularly scheduled meds and therapy. August 2021: The worst episode happened. Sam had the sam tremors/twitching in his back end, but was having issues with his back feet this time. I could not touch his back feet/pads without him *FREAKING* out like I was causing him to feel excruciating pain. We spoke with the Vet and we decided to add Gabopenton to the daily medication routine. So daily meds are now: 100MG Gabopenton in the AM .08MG Thyro-Tab in AM 300MG Gabopenton in the PM 90lb Meloxican in PM Within 2 weeks, we noticed a great change in Sam. He was clearly feeling a lot better and even began to take walks happily again. Until today, we had zero issues. This morning: 12/6/2021, Sam got up for breakfast like normal, ate, did his business and we gave him his morning meds and he went back to sleep, as he does every morning. Very soon after, he began having tremors - mostly in his legs/abdominal area, with some in his shoulders and upper back. Per the vet, he was given 200mg of additional Gabopenton - for 300mg, total - and we were asked to watch him for 2 hours. If nothing improved, we were to take him in. The meds did their job, for the most part, but he was still twitching 2 hours later, so he was seen. His vitals were good, and he had a through physical exam. He was pretty much back to normal by the time we got home. He slept quietly all day, and just had his dinner and PM medication. There is nothing I can say is a "trigger" for whatever this is. There's nothing that he is doing, eating, etc - that lines up with this. There isn't any physical exertion, injury, etc.   My next step would be to see a specialist - but I am not sure where to even start. We discussed a neurologist briefly today at our visit, but I am not sure that is the right start. Thank you in advance for reading this, and I do have some short videos I can send if you'd like to see them.   Sincerely, Sara (And Sam)

Hello!  What an interesting case.  Your vet has probably performed at least a rough neurological exam, so may have achieved quite specific localization of what is not working optimally, but it is not always straightforward.  Neurologists can often investigate in more detail, with more confidence, than GP vets and your films sound as though they may be useful in helping them to do this.  If you happen to find yourself in a position to film any more, try to film the eyes at various points, and their reaction when you call your dog during the episode, as this can be very telling.  The neurological system covers nerve changes within the brain, spinal cord and also at the level where the nerves affect the muscles, so most cases of tremors or imbalance do fall within their remit somewhere along the way.  The neuromuscular system can be affected by dietary factors (e.g. blood sugar, blood electrolytes) or pain (eg caused by orthopaedic disease).  If the neurologist feels that a different department is more appropriate, they will re-refer appropriately.  In big centres (often the type of centres where you find specialist neurologists), this can often be done internally, saving time, as within human hospitals.  If you decide that you would like a referral, the procedure would usually be to get a message to your vet (perhaps call them) asking them to go ahead and write a 'referral' letter (usually by e-mail these days) or make a phone call, to transfer the case.  The speed depends upon the perceived urgency.  In most cases you would be contacted at this point and an appointment made to see the referral vet, who will do tests of their own and liase with you, then refer the case back to your own vet as necessary once they have taken things as far as you would like them to.  It does sound as though referral may turn out to be useful.  It is always a good idea to ask for costs in advance.