Clinical signs, MRI findings and outcome in dogs with peripheral vestibular disease: a retrospective study

Abstract

Background: Vestibular dysfunction is relatively common in dogs, with a prevalence of 0.08% reported in primary veterinary care in the UK. There are several studies investigating how to differentiate between peripheral and central vestibular disease but only limited information regarding the possible underlying causes for peripheral vestibular dysfunction in dogs. This study therefore aimed to describe the clinical signs, magnetic resonance imaging findings (MRI), underlying causes and outcome in a large population of dogs diagnosed with peripheral vestibular disease. Results: One hundred eighty-eight patients were included in the study with a median age of 6.9 years (range 3 months to 14.6 years). Neurological abnormalities included head tilt (n = 185), ataxia (n = 123), facial paralysis (n = 103), nystagmus (n = 97), positional strabismus (n = 93) and Horner syndrome (n = 7). The most prevalent diagnosis was idiopathic vestibular disease (n = 128), followed by otitis media and/or interna (n = 49), hypothyroidism (n = 7), suspected congenital vestibular disease (n = 2), neoplasia (n = 1) and cholesteatoma (n = 1). Long-term follow-up revealed persistence of head tilt (n = 50), facial paresis (n = 41) and ataxia (n = 6) in some cases. Recurrence of clinical signs was observed in 26 dogs. Increasing age was associated with a mild increased chance of diagnosis of idiopathic vestibular syndrome rather than otitis media and/or interna (P = 0.022, OR = 0.866; CI 0.765-0.980). History of previous vestibular episodes (P = 0.017, OR = 3.533; CI 1.251-9.981) was associated with an increased likelihood of resolution of the clinical signs whilst contrast enhancement of cranial nerves VII and/or VIII on MRI (P = 0.018, OR = 0.432; CI 0.251-0.868) was associated with a decreased chance of resolution of the clinical signs. Conclusions: Idiopathic vestibular disease is the most common cause of peripheral vestibular dysfunction in dogs and it is associated with advanced age. Incomplete recovery from peripheral vestibular disease is common, especially in dogs presenting with cranial nerve enhancement on MRI but less so if there is previous history of vestibular episodes.

Clinical reasoning in canine vestibular syndrome: Which presenting factors are important?

“…Idiopathic vestibular disease was the most common condition in our study population. Although this is in agreement with previous reports, 9,17 it has also been suggested that otitis media interna should be considered the most common cause of peripheral vestibular disease in dogs. 1,5 Our study included exclusively cases referred to a specialist hospital, which could have favoured emergency presentations.…”

“…It is therefore possible that dogs with vestibular signs caused by otitis media interna will also display non‐neurological signs, such as head shaking, ear discharge and pain on opening of the mouth or palpation of the bullae 1 . It should however be noted that otitis media interna is not always caused by extension of otitis externa, and chronic otitis externa will not necessarily result in otitis media and interna 17,41 . This is in agreement with the findings of this study in which only two thirds of dogs with otitis media interna had a clinical history of previously diagnosed otitis externa, and otitis externa was also commonly observed in dogs suffering from other causes of vestibular syndrome (Table 1).…”

“…The facial and vestibulocochlear nerves enter the petrous part of the temporal bone through the internal acoustic meatus and are enclosed in a common dural sheath and have the same blood supply 38 . The pathophysiology of idiopathic facial nerve paresis and idiopathic vestibular disease is unclear 17,36 . It is further unclear if idiopathic vestibular disease without facial nerve involvement should be considered a different disease entity compared to acute vestibular disease of unknown cause with concurrent facial nerve paresis 35 .…”

The Use of Ondansetron for the Treatment of Nausea in Dogs With Vestibular Syndrome

“…36 Similar breeds were mentioned by some recently published studies consistent with our ndings. 2,37 In the present study, the median age at onset of neurological de cits was 115 months (9.58 years). Median age reported recently elsewhere ranged from 6.8 years to 12.68 years.…”

“…These signs are the most frequently observed clinical ndings consistent with vestibular syndrome. 2,32,37,41 In summary, although the sample size in this case series was small, the cases included appear to be representative for the commonly affected canine population by vestibular syndrome.…”