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Pathogenesis and pathophysiology of Meniére's disease
1Minnesota Ear, Head and Neck Clinic, Minneapolis 55454.
Abstract:
Meniére's disease, neither spontaneous nor inducible in animals, is studied only in patients. Natural history (epidemiology) shows a triad of major symptoms: vestibular, auditory, and aural pressure. One in 3 patients has bilateral Meniére's; over full lifespans, bilaterality approaches 50%. Aural pressure (74.1%) and positional vertigo during/between attacks (85.9%) are common. Clinical variants can persist for 25+ years. All forms have delayed onset and can occur years after incitement, after otosclerosis, infections like otitis media, syphilis, or trauma. Endolymphatic hydrops is found in all, most importantly in pars inferior (cochlear duct and saccule). Some (not most) cases show ruptures. The saccule can distend into the lateral semicircular canal. Symptomatic attacks are explained on physical/biochemical bases. Both longitudinal (slow) and radial (fast) flow seem operational, longitudinal in advanced Meniére's where membranous labyrinth replaces perilymph in scala vestibuli and vestibule. All forms result from endolymphatic absorptive dysfunction (in duct and sac), with mastoid and periaqueductal hypocellularity, hypodevelopment of Trautmann's triangle, and anterior displacement of lateral sinus. Secondary obstructions in ductus reuniens or utricolo-endolymphatic valve may explain atypical Meniére's (vestibular or cochlear alone).
Insights
Meniere's disease, a human-only condition, involves vestibular, auditory, and aural pressure symptoms. Research suggests endolymphatic absorptive dysfunction is the primary cause of this complex inner ear disorder.
Area of Science:
- Otolaryngology
- Neurology
- Pathophysiology
Background:
- Meniere's disease is exclusively studied in human patients due to lack of animal models.
- Characterized by a triad of vestibular, auditory, and aural pressure symptoms.
- Bilateral Meniere's affects one in three patients, approaching 50% over a lifetime.
Purpose of the Study:
- To investigate the underlying causes and pathophysiology of Meniere's disease.
- To explain the symptomatic attacks based on physical and biochemical factors.
- To explore the role of endolymphatic hydrops and absorptive dysfunction.
Main Methods:
- Analysis of natural history and epidemiological data.
- Examination of clinical variants and long-term persistence of symptoms.
- Pathophysiological investigation focusing on endolymphatic hydrops and fluid dynamics.
Main Results:
- Endolymphatic hydrops, particularly in the pars inferior (cochlear duct and saccule), is consistently found.
- Symptomatic attacks are explained by physical/biochemical mechanisms, including altered fluid flow.
- Endolymphatic absorptive dysfunction is identified as the root cause, linked to specific anatomical findings.
Conclusions:
- Meniere's disease results from endolymphatic absorptive dysfunction in the endolymphatic duct and sac.
- Anatomical abnormalities like mastoid hypocellularity and sinus displacement may contribute.
- Secondary obstructions can lead to atypical presentations of Meniere's disease.