Vestibular Syndrome in Dogs

Introduction

Failures of the vestibular system are among the more frequent neurological presentations in small animal practice. They can be regarded as clinically rewarding in that the neurological loss of function produces classical clinical signs, and initial recognition of most vestibular disorders usually poses no great difficulty. The next, perhaps more important, step is precise localization of the disease within the vestibular system; assessing the lesion as either peripheral (in the inner ear) or central (in the brain) may be a challenge. However, precise localization is essential, as this affects all subsequent decisions regarding diagnosis, prognosis and therapy, and the key question with “vestibular neurology” is therefore always: ear or brain? The answer is of fundamental importance for the patient, and this article aims to enable the reader to recognize vestibular disease, to distinguish between peripheral and central syndromes in a clinical setting, and to consider differential diagnoses for disorders of the peripheral vestibular system. Central vestibular disease will not be discussed in depth, as once this disorder has been recognized it is usually necessary to transfer the patient to a specialist center for MRI imaging and cerebrospinal fluid analysis.

Key Points

• Typical signs of a vestibular system disorder are generalized ataxia, nystagmus, head tilt and walking in circles.

• The clinician must determine if the peripheral (ear) or central (brain) section of the vestibular system is involved, as this is essential for all further diagnostic and therapeutic decisions.

• A combination of vestibular symptoms and unilateral facial nerve paralysis and/or Horner’s syndrome without other neurological deficits invariably indicates middle or inner ear disease.

• Vertical nystagmus almost invariably indicates a central vestibular disorder.

• Peripheral vestibular disease may be diagnosed and treated by the general practitioner. Patients only require referral to a specialist for further diagnostic imaging when initial therapy fails.