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The membrane rupture theory of Menière's disease--is it valid?
D H Brown1, J A McClure, Z Downar-Zapolski
1Department of Otolaryngology, University of Western Ontario, London, Canada.
Abstract:
The Membrane Rupture Theory states that the acute attack of Menière's disease occurs when endolymph, with its high potassium ion concentration, escapes into the perilymph and surrounds the first-order neuron. Initially, this causes partial depolarization of the nerve and an increased resting discharge, followed by complete depolarization. Clinically, one would expect an initial irritative nystagmus (toward the affected side) followed by a paralytic nystagmus (toward the unaffected side). To confirm this, the guinea pig perilymphatic space was perfused with an artificial endolymph solution. The results confirmed an irritative/paralytic sequence of nystagmus that differs from the pattern of spontaneous nystagmus observed with ENG monitoring during the acute attack of Menière's disease. Early in the attack, one observes a paralytic nystagmus followed by a secondary nystagmus beating toward the affected side (similar to an irritative nystagmus) as the patient recovers. This raises questions about the validity of the Membrane Rupture Theory.
Insights
The Membrane Rupture Theory suggests Meniere's disease attacks involve endolymph escaping into perilymph. Guinea pig studies showed an irritative/paralytic nystagmus, challenging the theory's clinical predictions for Meniere's disease.
Area of Science:
- Neurology
- Otolaryngology
- Physiology
Background:
- Meniere's disease is characterized by acute attacks.
- The Membrane Rupture Theory proposes endolymphatic fluid shifts cause these attacks.
- This theory predicts a specific sequence of nystagmus during an attack.
Purpose of the Study:
- To investigate the validity of the Membrane Rupture Theory.
- To compare predicted nystagmus patterns with observed patterns in Meniere's disease.
Main Methods:
- Perfusion of guinea pig perilymphatic space with artificial endolymph.
- Observation and recording of nystagmus in response to perfusion.
- Comparison of experimental nystagmus with clinical electro-nystagmography (ENG) data from Meniere's disease patients.
Main Results:
- Experimental perfusion induced an irritative/paralytic nystagmus sequence in guinea pigs.
- This observed sequence differed from the spontaneous nystagmus pattern during acute Meniere's disease attacks.
- Clinical observation shows a paralytic nystagmus early in an attack, followed by a secondary irritative nystagmus.
Conclusions:
- The observed nystagmus pattern during Meniere's disease attacks does not align with the predictions of the Membrane Rupture Theory.
- The findings question the direct applicability of the Membrane Rupture Theory to the acute phase of Meniere's disease.
- Further research is needed to fully understand the pathophysiology of Meniere's disease attacks.