Recurring episode of vertigo Whirling vertigo is usually sudden Companied with nausea and vomiting Persist for several hours attacks last longer than 24 h make the diagnosis of MD doubtful
Fluctuating Hearing loss Eye Ear Nose Throat Early fluctuation of low Wednesday, October 20, 200 1025 4377134645 1909 VetuM320233371 0 11/1/33 Frequencey hearing loss and later involvement of the high 率4 frequencies An eventual decline over 5-10 years and subsequent stabilization with a flat moderate to severe hearing 12-10331 speech discrimination falling to uoax93正(1m95 approximately 50%. Making the use of hearing aid difficult There is also diplacusis and loudness recruitment
Hearing loss Hearing loss may be due to the hydrops in membrane of cochlea, which lead to restrict movement of basal membrane Neural degeneration of unmyelinated afferent processes at the EM may Cross section of cochlea explain the clinical finding of Scala Tectorial media progressive loss of speech discrimination despite the presence of vestibuli intact HC and sgN Scala tympanI Inner Outer
Biochemical and mechanica/ias theories Proposed by lawrence, Mccabe and Schuknecht that a sudden rupture of the thin distented membranous labyrinth results in flooding of the perilymphatic space with potassium-rich neurotoxic endolymph, causing paralysis of sensorineural structure which in turn results in a sudden attack of vertigo and hearing loss
Aural pressure and fullness One possibility is that this might be mediated by sensory nerves supplying the middle ear aspect of the round and oval Windows Another possibility is sensory innervation of dura mater surrounding LSC the endolymphatic sac