Wait, what? Did I read that correctly? Yes, you did! What do you call acute onset, transient vestibular signs? Vestibular paroxysmia (VP)! What do you call it if you have interictal spike and wave forms on EEG (which suggest an epileptic focus)? You guessed it... vestibular epilepsy (VE).
What is Vestibular Epilepsy?
In human neurology, there is a form of epilepsy in which patients have acute onset vestibular signs (drifting, rolling, nystagmus) that seconds to minutes. If the onset is associated with body position change, it is considered a paroxysmia (VP). However, when an EEG is performed, human patients with vestibular epilepsy will show classic changes consistent with seizures in the temporal and parietal lobes. The big differentiator between paroxysmia and epilepsy is the response to treatment and the presence of changes on EEG. In veterinary patients there are very few studies evaluating this form of epilepsy but clinically perhaps some of you can think of a patient (or two) with similar clinical signs? We see this, albeit rarely!
How To Diagnose Vestibular Epilepsy
Diagnosing VE in veterinary medicine can be challenging. Patients will present with repeated, transient vestibular signs and are normal on examination. Animals with underlying vestibular disease (think central or peripheral vestibular disease) often have a residual positional strabismus, or mild head tilt, or another lingering deficit. Animals with VE do not! (At least not as far as we know...yet.) In a recent study published in JVIM (2024), the authors identified 10 dogs with suspected VE. All 10 dogs were treated with an anticonvulsant drug (or 2). Five of 10 dogs received just levetiracetam, 2 of 10 received Levetiracetam + phenobarbital, and 1 of 10 received levetiracetam and gabapentin or just phenobarbital. Half of the dogs receiving levetiracetam only had resolution of seizures and the other 5 had a sustained reduction. The one dog receiving phenobarbital and levetiracetam had marked improvement after phenobarbital was added, but not before.
What Is The Take Away Message?
1) Be aware of transient vestibular signs - maybe your patient has seizures!?
2) If seizures are suspected, try levetiracetam (22 mg/kg PO q8h standard release; 30 mg/kg PO q12h extended release)
3) The dogs in this study had idiopathic vestibular epilepsy (because the study selected for those cases) but vascular disease (such as transient ischemic attacks; TIA) can cause transient vestibular disease and maybe vestibular epilepsy (according to a different study).
Not sure what your patient has? Catch a video and set up a consultation! I'm always happy to rule OUT neurologic disease and I am here to help when we rule it IN. Have a great week! I hope those of you celebrating Easter had a nice, relaxing holiday. I look forward to working with you soon!