[Furosemide test for diagnosis of endolymphatic hydrops: a clinical exploration]

Furosemide test (FT) is a clinical method for the diagnosis of endolymphatic hydrops (EH). Immediately preceding i.v. injection of 20 mg furosemide, a caloric test was performed with 50 micromilligrams of water at 30 degrees C. Nystagmography was employed to measure the maximum slow velocity of caloric nystagmus. The test was repeated one hour after the injection. The two sets of data were then compared. An increase beyond 22.97% was defined as positive. The first group was composed of 54 patients of EH as the experimental group, and the second group 54 patients with vertigo of non-EH as control. The positive rates of the two groups were 70.4% and 25.9% respectively. It showed that FT was useful for detecting EH. The percentage of directional preponderance (DP) was obviously descended in the two groups after i.v. furosemide. Descending rate was 77.8% (21/27) in the first group, which had reached the normal value in 9 cases. It was showed that DP was important also for criticizing FT. The hearing of all subjects was not damaged. When the renal function of the subject was normal and not combined with the use of aminoglycoside antibiotics, the dose of FT was not dangerous to the hearing and had few side reactions. The mechanism of dehydration in hydropic labyrinth was presumed to be acute systemic diuresis, but the effect in inner ear was unknown.