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• Endolymphatic hydrops causes pressure and mechanical displacement of inner ear organs which then precipitates the attacks.

As a result of the increased pressure in the inner ear and the ensuing distention caused by hydrops, there is irritation of the nerve hairs in the utricle and saccule resulting in additional symptoms of dizziness, imbalance, and disequilibrium. The damage from periodic, intense disturbance to the cochlear duct nerve cells causes hearing loss. Since there is greater pressure at the apex of the cochlea where the nerve cells are sensitive to low frequency sounds, any disturbance affects that area first. For this reason, the first symptoms of hearing loss usually involve low-frequency tones. The fluctuation of endolymphatic pressure is the reason for fluctuation of symptoms in Meniere's disease.

It is not clear if hydrops is a result of obstruction of the endolymphatic duct, overproduction of fluid, or faulty resorption of normal amounts of fluid. It is also not clear whether endolymphatic hydrops is the cause or the result of Meniere's disease since there are cases of endolymphatic hydrops that are asymptomatic.

There is no universally accepted classification system for Meniere's disease. Some researchers describe four different types of Meniere's disease:

• Typical Meniere's disease - patient develops all the symptoms of Meniere's disease
• Atypical Meniere's disease- patient develops either vestibular or hearing symptoms but does not develop full-blown Meniere's disease with all symptoms
• Cochlear Meniere's disease - patient develops fluctuating hearing loss with aural pressure and tinnitus but no vestibular symptoms
• Vestibular Meniere's disease - patient develops episodic vertigo and disequilibrium (loss of equilibrium) without aural symptoms