Head tilt and nystagmus Laurent Garosi

Abstract

Head tilt and nystagmus are frequent clinical manifestations of a vestibular disorder, although a head tilt alone may be observed with otitis externa or other causes of aural irritation. The vestibular system is essential in maintaining balance and preventing the animal falling over by keeping and adapting the position of the eyes, head and body with respect to gravity. It is therefore not surprising that disease of the vestibular system results in some of the most dramatic and distressing neurological signs. In addition to head tilt and abnormal nystagmus, positional strabismus, falling, rolling, leaning, circling, and ataxia commonly result. Clinical signs of vestibular disease may be a result of lesions involving either the receptor organs in the inner ear or the vestibular portion of CN VIII (i.e. peripheral vestibular disease) or lesions involving the brainstem vestibular nuclei or vestibular centres in the cerebellum (i.e. central vestibular disease). If an animal is presented with a head tilt and nystagmus, a lesion must be localized to these particular sections of the vestibular apparatus before an appropriate differential diagnosis list can be established and further testing conducted.