ORGAN OF CORTI Meniere’ s Disease Chunfu dai Otolaryngology Department Fudan University
Prevalence Incidence is 54 100000 in Japan 15/100000nUs,46/100000 n Sweden 100/100000inUK The large differences are due to geographic, genetic, ethnic or environmental factors or different diagnostic criteria
Background In1861, Meniere described a syndrome In1938, Hallpike and Yamakawa reported the finding of endolymphatic hydrops in temporal bone from patients with MD
Background In1972, AAOo report also defined two sub-varieties cochlear and vestibular mD In1985 AAO-HNS updated the term Md should be restrictive and include only those cases with complement of classic symptoms and findings of the disease presumed to result from idiopathic endolymphatic hydrops
Pathogenesis Radial circulation Longitudinal flow hair cells hair cells
Pathology Endolymphatic hydrops duct and saccule but were pves the cochlear The hydrops principally involv Cross section of cochlea t obvious in the Tectorial utricle and ampullae of semicirclar canals The walls of the membranous labyrinth may vestibula show areas of thinning outpouching and ruptures Decrease in the amount of loose connective tympani tissue around the endolymphatic sac, hypoplasia hair cells membrane of vestibular aqueduct, and decreased vascularization of the sac and perisaccular fibrosis were also observe
Tympanic Scala(Perilymph) Spiral Ligament Basilar Membran CD Vestibular Scala (Perilymph)
Pathology Vestibular fibrosis Proliferation of fibrous tissue within the vestibule is often observed which sometimes results in the formation of band of fibrous tissue between the under-surface of the footplate and the utriclar 内耳道 macula 球囊神经 椭圆囊隐窝 a This phenomenon may account for 椭圆囊 a positive Hennebert' s sign, 前庭 耳蜗底周 Which observed in about 30% of 1.9mm ears with md 2. 0mm 1.5mm
ORGAN OF CORTI Pathology Hair cell loss a In most of cases with MD, light microscope has failed to demonstrate loss of HC in cochlear and vestibular organ In advanced disease, loss of cochlear HC atrophy of support cells, distortion and atrophy of tectorial membrane and atrophy of cristae were identified a EM could identified fusion of cilia, disruption of cuticular bodies and basal ward displacement of some OHC With loss of contact with the cuticular plate
Pathology Neuronal cell SGN and Scarpa s ganglion neuron are normal in most patients 10% of temporal bones showed an Cross section of cochlea isolated loss of cochlear neurons in Scala the apex. Loss of nerve fibers in the Tectorial membrane osseous spiral lamina EM identified striking reduction in vestibu the number of afferent nerve endings and afferent synapes at the spirs soa base of both ihc and ohc tympanI Inner hair cells Outer Basil hair cells