Endolymphatic hydrops. An overview and classification.

Endolymphatic hydrops (EH) is a pathological condition which is the final common manifestation of a variety of otologic insults. In this paper we develop a classification which, on the basis of clinical and pathological data, distinguishes symptomatic and asymptomatic forms. Clinical case histories and temporal bone studies are presented to illustrate and substantiate this classification. The symptomatic form becomes evident by the hallmark symptoms of episodic vertigo and fluctuating hearing loss. The asymptomatic form is silent. Interconversion from one form to another may occur over time. Each of the forms can be subdivided, according to etiology, into embryopathic, acquired, and idiopathic types. The embryopathic type comprises those cases in which some noxious influence interferes with prenatal labyrinthine development. The acquired type includes those cases in which a documented insult, be it inflammatory or traumatic, is suffered by a previously normal labyrinth. The inflammation may be viral, bacterial, or spirochetal in nature, while the traumatic event may be either accidentally or surgically sustained. The idiopathic type includes cases in which the instigating event precipitating the EH is unknown. Menière's disease represents merely one example of the EH group of disorders, namely symptomatic idiopathic EH.