Increased urinary volumes in symptomatic Ménière's Disease.

OBJECTIVE: The purpose of the research is to test the measurement of the total urinary volume, induced by the diuretic osmotic action of mannitol, in a group of symptomatic MD patients and in healthy controls. RESULTS: An altered excretory urinary volume after mannitol challenge was observed in symptomatic MD (874.3 ± 302.1) compared to healthy volunteers (361.7 ± 181.6) (p = 0.0001). This easy and self-administered method might be proposed to replace the analysis of the urinary sugars' concentration in symptomatic MD patients.

Effect of thirst challenge on ADH levels in patients with bilateral Menière's disease.

The aim of the study was to investigate plasma ADH levels and plasma/urine osmolality in patients suffering from bilateral Menière's disease since a disturbance in the water household after thirst challenge is a suspected pathogenic factor in the development of this disease. In this study the plasma ADH levels and plasma/urine osmolality of bilateral Menière's disease patients under thirst challenge were investigated to show whether the water balance is affected. 9 patients with bilateral Menière's disease and 9 healthy controls skipped water intake for 12 h. Plasma ADH, plasma/urine osmolality, and electrolytes were measured after this thirst period as well as 8 h later after food and fluid intake. During food and fluid intake the patients demonstrated a slightly higher plasma ADH level and plasma osmolality than controls, whereas at the end of the thirst period patients and the controls showed no significant change. Instead the urine osmolality differed significantly (p<0.001): showing a high urine osmolality in controls and an almost stable urine osmolality in patients after thirst challenge. This indicates that the water balance in patients is likely different from that of controls. These observations point to ADH and its target aquaporine 2 as keyplayers in the pathophysiological events leading to the development of Menière's disease.