About 5 years ago I lost a horse to Polyneuritis Equi. It started with mild neuro symptoms, right side hind end weakness and atrophy, which got progressively worse. In my case the horse also had cranial issues , same side, lost vision in that eye. NOTE that this is pretty rare, so not many vets know much about it. Believed to be auto immune related.
We did not notice the tail/anus paralysis in this case, only the significant atrophy. We did, however notice signs of paralysis in his face, head, and he could only graze with head tilted. Edited to add, looking back at reports, there was some weakness in tail/anus area noted, though it appeared a couple weeks after the initial evaluations. We tested for the usual (EpM, Lyme, etc) but then did a cranial MRI, which i can only summarize as a hot mess. Horse spent about 3 weeks or so at Univ Fla as we tried to figure out what was going on.
Sincerely hoping you find some simpler, treatable answers. This was my worst nightmare…
