Spontaneous nystagmus: Pathophysiology of Meniere’s disease

Abstract

Meniere’s disease is characterized by dizziness and is caused by inner ear disorder. Its characteristic histopathological finding is endolymphatic hydrops. Meniere’s disease is characterized by a triad of repeated vertigo attack, fluctuating hearing loss, and tinnitus. In this session, we comment on the mechanisms of spontaneous nystagmus using mainly the results from animal experiments.

From clinical practice experience and experimental studies, the formation of endolymphatic hydrops relates to the dysfunction of the endolymphatic sac and a high plasma level of the antidiuretic hormone. Thus, the mechanism that dizziness occurs when endolymphatic hydrops is formed remains unclear. The results of the animal experiment showed that an increase in perilymph potassium ion concentration is associated with the formation of endolymphatic hydrops. A high concentration of perilymph potassium causes spontaneous nystagmus to change from the stimulus to the paralytic state. The single nerve units of the vestibular nerve disappear after the rise in the firing rate. Hence, considering these results, an increase in perilymphatic potassium ion concentration is regarded as the cause of dizziness.