A comparison of the furosemide and glycerol tests for Meniere's disease. With special reference to the bilateral lesion.

The feasibility of furosemide test for the detection of endolymphatic hydrops has previously been discussed (Authors, 1973, 1975). The glycerol test also has been reported as being effective for the same purpose but only in Meniere patients with fluctuating hearing loss (Klockhoff & Lindblom, 1966). In 48 patients with Meniere's disease, both the furosemide test (F-test) and the glycerol test (G-test) were performed on 51 ears including 3 cases of bilateral involvement. The average value of urine volume in the F-test was significantly greater than that for the G-test. The decrease in tinnitus was 40% in the former, 45% in the latter. The F-test yielded a positive rate of 73%, and the G-test, 45%. The results were thus: positive in the both tests, i.e., F+: G+ were 17 (33%); F+: G-, 20 (39%); F-: G+, 6 (12%), and both negative, F-: G-, only (16%). The side effects of the F-test were nil, but those of the G-test were as follows: headache (29%), nausea (4%), and increase in tinnitus (9%). The response increase of the hydropic labyrinth caused by the two kinds of systemic dehydration over-lapped in part and differed in part, as a result of the differing diuretic mechanisms and their respective affinities to the cochlea and the vestibulum. The furosemide test may be based on the action of the vestibular response type, which is caused by natriuretic dehydration accompanying the more sensitive response increase in caloric-induced nystagmus, while the glycerol test may be based on the action of the cochlear response type, owing to osmotic diuresis manifested as hearing shift. The correlation between labyrinthine hydrops and dehydration was discussed and it was concluded that these double test were quite adequate methods for choice of treatment of not only unilateral Meniere's disease in its various stages but also in bilateral involvements.