What is Menière's disease? A contemporary re-evaluation of endolymphatic hydrops

Abstract

Menière's disease is a chronic condition with a prevalence of 200-500 per 100,000 and characterized by episodic attacks of vertigo, fluctuating hearing loss, tinnitus, aural pressure and a progressive loss of audiovestibular functions. Over 150 years ago, Prosper Menière was the first to recognize the inner ear as the site of lesion for this clinical syndrome. Over 75 years ago, endolymphatic hydrops was discovered as the pathologic correlate of Menière's disease. However, this pathologic finding could be ascertained only in post-mortem histologic studies. Due to this diagnostic dilemma and the variable manifestation of the various audiovestibular symptoms, diagnostic classification systems based on clinical findings have been repeatedly modified and have not been uniformly used in scientific publications on Menière's disease. Furthermore, the higher level measures of impact on quality of life such as vitality and social participation have been neglected hitherto. Recent developments of high-resolution MR imaging of the inner ear have now enabled us to visualize in vivo endolymphatic hydrops in patients with suspected Menière's disease. In this review, we summarize the existing knowledge from temporal bone histologic studies and from the emerging evidence on imaging-based evaluation of patients with suspected Menière's disease. These indicate that endolymphatic hydrops is responsible not only for the full-blown clinical triad of simultaneous attacks of auditory and vestibular dysfunction, but also for other clinical presentations such as "vestibular" and "cochlear Menière's disease". As a consequence, we propose a new terminology which is based on symptomatic and imaging characteristics of these clinical entities to clarify and simplify their diagnostic classification.

Keywords: Classification; Diagnosis; Endolymphatic hydrops; Magnetic resonance imaging; Menière’s disease.

Fig. 1

Different approaches used to analyze the impacts of Menière’s Disorder all of which influence generic measures of quality of life (QoL). The disease-specific model can be built from impairments caused by symptoms, open-ended questions, activity limitations or participation restriction (modified from [32]). All these different measures display specific aspects of QoL but are not interchangeable with the outcome of generic QoL instruments

Fig. 2

Assessment of vestibular endolymph space in a right inner ear using regions of interest (ROI). The outer ROI defines the cross-sectional area of the vestibulum at the level of the horizontal semicircular canal (“vest”). The inner ROI defines the endolymphatic space inside the vestibulum (“hyd”). a The vestibular endolymph ratio in this patient is 0.35, corresponding to mild EH. b The vestibular endolymph ratio in this patient is 0.64, corresponding to significant EH (Figure reproduced from [61])

Fig. 3

Entry of intratympanically applied drugs into the inner ear perilymph space (white) via the round and oval windows. Endolymph space is marked in red