Modifications of the Osmotic Pressure of Perilymph and Endolymph: An Hypothesis on the Pathogenesis of Menière's disease

Abstract

The introduction of a saturated solution of NaCI into the middle ear of a cat or guinea pig provoked a biphasic vestibular spontaneous picture, which is composed of a 1st phase of “irritative” signs (nystagmus beating towards the injected side, etc.) and of a 2nd phase of “paralytic” signs (nystagmus beating towards the non-injected side, etc). Histologi-cal, electrophysiological, biochemical, and biophysical (osmotic pressure measurements) investigations have been carried out in many series of experiments performed by the author and his collaborators. It has been demonstrated that the changes of osmotic pressure between the peri-lymph and the endolymph are the essential pathogenetic factors of all clinical, histological, and electrophysiological manifestations occurring in the experiment. Close analogies are indicated between the effects of the experiment and the pathogenetic factors and evolution of Meniere's acute attacks: in fact, a Meniere's attack shows “irritative” signs followed by “paralytic” signs. Furthermore, in these experiments and in a Meniere's attack there are identical histological pictures of a “collapse” of the endolymphatic duct.