Disorders of the vestibular system.

Disorders of the vestibular system are common in veterinary practice and result in a clinical syndrome characterized by head tilt, asymmetric ataxia, and nystagmus. These signs may occur with lesions involving the peripheral or central vestibular structures. Careful neurologic evaluation of the animal and knowledge of surrounding neuroanatomic structures and their functions enable the clinician to differentiate between peripheral and central disorders. Conditions resulting in peripheral vestibular symptoms include idiopathic syndromes, otitis interna, trauma, neoplasia, drug-induced ototoxicity, and congenital disorders. Radiographs of the petrous temporal bone and tympanic bulla and examination of the tympanic membrane are useful in determining the specific etiology. Central vestibular dysfunction may result from inflammatory CNS diseases, neoplasia, trauma, thiamine deficiency, and storage diseases. Cerebrospinal fluid analysis, skull radiographs, and computed tomography are diagnostic tests useful in animals with central vestibular symptoms. Once the etiology is identified, specific therapy may be provided and a more accurate prognosis can be determined.