[Considerations on the pathogenesis of the cochleo-renal syndrome (author's transl)]

The histological findings in two cases of Alport's syndrome are presented. Damage within the inner ear is mainly represented in the vascular stria region and it seems that the inner ear damage pattern tallies with the renal alterations. Glomerular basement thickening and splitting are the first and pathognomonic findings together with confluence of the epithelial feet. Later on, the increase in volume in the epithelial cells and the tremendous enlargement of the glomerular basement membranes leads to an obliteration of glomerular capillaries. In the first described case a subtotal loss of stria vascularis seems to be the reason for a degeneration of the inner and outer hair cells as well as of some spiral ganglion cells. The second case revealed only a slight edema of the stria vascularis and apical protrusions of cytoplasm, sometimes vacuolated. Whereas in the basal turn most of the inner hair cells had disappeared, in the upper turns we observed a slight degeneration of the inner hair cell but intact outer hair cell system. Although in Alport's syndrom there are--according to the literature--no constant findings, our observations allow us to assume that inner ear damage in the cochleo-renal syndrome is secondary to the kidney disease.