Idiopathic Geriatric Vestibular Disease
If I had a dime for every time a client told me their dog had a stroke (usually "several years ago") and that they suddenly were dizzy, and then, suddenly got better, I'd be rich. Or at least I could by myself a soda. :)
Idiopathic Geriatric Vestibular Disease is Not Caused by a Stroke
Human strokes happen suddenly, and can cause signs such as hemiparesis, hemifacial weakness, and often resolve over time so it is reasonable that a stroke would be confused with the canine idiopathic geriatric vestibular disease (IGVD). But they are different! Strokes occur at the level of the brain, brainstem, or cerebellum, and IGVD localizes to the peripheral vestibular system.
What is Idiopathic Geriatric Vestibular Disease?
As the name implies, we have yet to find the etiology. Several proposed causes have been postulated but none confirmed. Clinical signs include:
1) Acute onset vestibular signs (head tilt, nystagmus, vestibular ataxia, positional strabismus)
2) NO evidence of ipsilateral hemiparesis (weakness on the same side as the head tilt)
3) NO evidence of ipsilateral paw replacement deficits. Some older dogs have unrelated or preexisting paw replacement deficits. If the deficit involves both pelvic limbs, equally, or a contralateral limb to the head tilt, the odds are strong that the deficit is unrelated to the vestibular signs.
4) NO mentation changes (obtunded, stupor, coma).
5) NO evidence of hypothyroidism, otitis media/interna, neuritis or peripheral/ear neoplasia
Options 2-4 above help you localize the lesion to the peripheral system, but that is just a localization. Options 1 and 5 help you eliminate the other differential diagnoses that could also cause peripheral vestibular disease and thus, narrow the diagnosis to idiopathic geriatric vestibular disease.
Treatment
Treatment for IGVD is supportive. Steroids, antibiotics and NSAIDs do not improve clinical signs. Signs typically begin to resolve within 48 hours of the onset, and have reached a state of stability by 30 days. The most marked improvement typically occurs in the first 14 days. Supportive care with anxiolytics (diazepam, trazodone, other), antivertigo drugs (meclizine, ondansetron), and nutritional support may allow the animal to be more comfortable during the recovery process. Clean, dry bedding with frequent comfort checks are important for non-ambulatory dogs to minimize bed sores and other complications.
Prognosis
Dogs with IGVD have some of the most severe clinical signs but have a very good long-term prognosis! Intensive supportive care is important in the first few days. Most dogs will recover to a functional state within 1 week and return to baseline within 30 days. Importantly, the head tilt is often permanent!! Please be sure to inform clients of this, otherwise they may think the dog is still clinically affected months and years after the signs have otherwise resolved.
Please let me know if you have a dog with vestibular disease that you feel would benefit from an evaluation. I look forward to working with you soon. Have a great week!