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PubMed1990

Rotatory recovery nystagmus: an important localizing sign in endolymphatic hydrops.

Localizing the ear responsible for vertigo attacks may be exceedingly difficult in patients with delayed endolymphatic hydrops, vestibular Ménière's disease or bilateral Ménière's disease. This has important clinical implications when planning operative treatment. We present a case of delayed endolymphatic hydrops to exemplify these difficulties and demonstrate the localizing value of recovery nystagmus. We stress the importance when possible of monitoring patients with endolymphatic hydrops for recovery nystagmus during acute vertigo attacks. Monitoring should include direct eye observation as pure rotatory nystagmus escapes detection on electronystagmography.

Aged↗

PubMed1997

Diagnostic testing for endolymphatic hydrops.

The development of a sensitive and specific diagnostic test for endolymphatic hydrops has eluded investigators for over 30 years. The absence of such a test has hampered basic and clinical research into Meniere's disease and related entities. Presently used tests are limited in their applicability because of their low sensitivity and specificity and a poor understanding of the underlying physiologic principles. Despite this, it is generally agreed that some of these studies have merit in selected situations. This article reviews the present state of diagnostic testing for endolymphatic hydrops. The use of nonspecific studies, such as basic audiometry and tests for recruitment, and "specific" studies, such as electrocochleography and dehydration testing, are critically reviewed.

Audiometry, Evoked Response↗

PubMedDate not supplied

Localization, frequency, and severity of endolymphatic hydrops and the pathology of the labyrinthine membrane in Menière's disease.

The localization, frequency, and severity of endolymphatic hydrops in 22 temporal bones of 16 individuals with Meniere's disease were studied histopathologically. Endolymphatic hydrops was more often observed in the pars inferior (22/22) than in the pars superior (13/22) of the temporal bone, and severe hydrops was observed most frequently in the saccule, followed by the cochlea, the utricle, and the three semicircular canals. In the cochlea, the most severe hydrops was observed in the apical turn, followed by the hook portion, the middle turn, and the basal turn. Clinically interesting observations regarding endolymphatic hydrops included bulging into the perilymphatic space of the vestibule. In 17 of 22 bones the saccular membrane bulged into the vestibule laterally and was attached to the footplate of the stapes. In two of 22 bones, Reissner's membrane in the hook portion of the basal turn of the cochlea bulged superiorly into the vestibule, occupying most of the perilymphatic space of the vestibule.

Cochlea↗

PubMedDate not supplied

[Morphological features of experimental transient endolymphatic hydrops].

This paper describes a method for simulating transient endolymphatic hydrops based on the generation of vasomotor disorders in the labyrinthine artery area. The method is based on a deep short-term chloroethyl freezing of the lateral surface of the animal surface in the projection of the spinal artery. In histological terms, hydrops is characterized by two factors: vascular lesions (hyperemia of the vascular stripe, venous congestion) and changes in physico-chemical parameters of labyrinthine fluids (edema of cell elements of the labyrinth, membrane deformation, precipitation of the granular-reticular residue in the endo- and perilymphatic spaces). This method can be used to study the origin of endolymphatic hydrops during Ménière's disease, to develop new approaches and to give a pathogenetic substantiation of existing approaches to the treatment of Ménière's disease.

Animals↗

PubMed1989

Electrocochleographic changes in endolymphatic hydrops induced by type II collagen immunization through the stylomastoid foramen.

Changes in action potential (AP) and summating potential (SP) were investigated in guinea pigs immunized with type II collagen through the stylomastoid foramen. Endolymphatic hydrops could be induced in four of 11 guinea pigs. The striking feature of the electrocochleographic waveform in guinea pigs with endolymphatic hydrops was the negative SP recording in response to high frequency tone bursts. Furthermore, abnormal changes in AP were observed in three of four hydropic guinea pigs. Morphologic study of the cochleas in these three guinea pigs with light microscopy revealed spiral ganglion cell degeneration in addition to endolymphatic hydrops and almost normal sensory hair cells. These results suggest that guinea pigs with hydrops as produced by our procedure can serve as a useful model of Meniere's disease, that autoimmune response may play an important role in the etiopathogenesis of Meniere's disease, and that spiral ganglion cell degeneration together with endolymphatic hydrops seems to contribute to abnormal changes in AP.

Action Potentials↗

PubMed1990

Endolymphatic hydrops precipitated by haemodialysis.

We report a case of endolymphatic hydrops preceded by haemodialysis in the contralateral ear of a patient with known Menière's disease, and discuss the possible mechanism. It is suggested that the sudden decrease of plasma osmolality during haemodialysis acts as a reverse glycerol test. The audiometric and electrophysiological recordings pre- and post-dialysis and the induction of the Menière's triad of symptoms during dialysis, were strongly indicative of the presence of endolymphatic hydrops.

Aged↗

PubMed1989

Meniere's syndrome and endolymphatic hydrops. Double-blind temporal bone study.

A systematic double-blind assessment of case histories and histopathologic findings in temporal bones in the collection at the Massachusetts Eye and Ear Infirmary was performed to test the hypothesis that clinical Meniere's syndrome is associated with endolymphatic hydrops demonstrated histopathologically at death. Thirteen of 13 cases of clinical Meniere's syndrome were found to have endolymphatic hydrops not attributable to other causes. However, some patients with idiopathic endolymphatic hydrops did not exhibit clinical Meniere's syndrome as revealed in their medical records. These results challenge the dogma that endolymphatic hydrops per se generates the symptoms of Meniere's syndrome.

Aged↗

PubMedDate not supplied

Cochlear potentials and their modulation by low-frequency sound in early endolymphatic hydrops.

Seventeen guinea pigs were unilaterally operated to produce endolymphatic hydrops. After 2 wk (9 animals) or 4 wk (8 animals), extracochlear electrophysiological responses to tone bursts of several frequencies were recorded in both the operated and non-operated ears. In addition, modulation by low-frequency (29 Hz sinusoidal bias) sound of the responses to 8 kHz tonebursts was measured. After the electrophysiological measurements, the animals were killed and examined histologically. Four weeks after the operation, cochlear microphonics in response to a 500 Hz tone burst and to the 29 Hz bias were significantly smaller in the operated ears. The summating potential showed a tendency to be larger in the operated ears. The compound action potential input-output curves for 2 kHz probes showed a small threshold shift accompanied by steep slopes, reminiscent of recruitment. Modulation of summating potentials by the low-frequency bias was smaller on the operated side. In most cochleae an endolymphatic hydrops was observed. Three cochleae showed a collapse of Reissner's membrane.

Acoustic Stimulation↗

PubMed2005

Pathophysiology of Meniere's syndrome: are symptoms caused by endolymphatic hydrops?

BACKGROUND: The association of Meniere's syndrome with endolymphatic hydrops has led to the formation of a central hypothesis: many possible etiologic factors lead to hydrops, and hydrops in turn generates the symptoms. However, this hypothesis of hydrops as being the final common pathway has not been proven conclusively. SPECIFIC AIM: To examine human temporal bones with respect to the role of hydrops in causing symptoms in Meniere's syndrome. If the central hypothesis were true, every case of Meniere's syndrome should have hydrops and every case of hydrops should show the typical symptoms. METHODS: Review of archival temporal bone cases with a clinical diagnosis of Meniere's syndrome (28 cases) or a histopathologic diagnosis of hydrops (79 cases). RESULTS: All 28 cases with classical symptoms of Meniere's syndrome showed hydrops in at least one ear. However, the reverse was not true. There were 9 cases with idiopathic hydrops and 10 cases with secondary hydrops, but the patients did not exhibit the classic symptoms of Meniere's syndrome. A review of the literature revealed cases with asymptomatic hydrops (similar to the current study), as well as cases where symptoms of Meniere's syndrome existed during life but no hydrops was observed on histology. We also review recent experimental data where obstruction of the endolymphatic duct in guinea pigs resulted in cytochemical abnormalities within fibrocytes of the spiral ligament before development of hydrops. This result is consistent with the hypothesis that hydrops resulted from disordered fluid homeostasis caused by disruption of regulatory elements within the spiral ligament. CONCLUSION: Endolymphatic hydrops should be considered as a histologic marker for Meniere's syndrome rather than being directly responsible for its symptoms.

Adult↗

PubMed1998

Induction of endolymphatic hydrops in the guinea pig by perisaccular deposition of sepharose beads carrying and not carrying immune complexes.

We tried to induce endolymphatic hydrops in guinea pig cochleas by unilateral, perisaccular deposition of sepharose beads carrying immune complexes. Controls consisted of the deposition of sepharose beads without immune complexes and the contralateral, untreated ear. The effects of the treatment were studied by light microscopy and electrophysiological recordings of the gross cochlear potentials 1, 2, and 6 weeks after treatment. Each condition included six animals. Analysis of variance of the morphometric data concerning the ears treated with deposition of the beads showed a statistically significant difference (P = 0.04) between the degree of hydrops found for the beads with immune complexes and for those without. The difference between the treated ears and the contralateral untreated ears was significant (P = 0.01) for the beads with immune complexes and not significant (P = 0.8) for those without immune complexes while there was no significant effect of post-treatment time interval. Analysis of variance of the electrophysiological data, collected in response to tone bursts at the apex of the cochlea, showed no significant differences between the results for the beads with and without immune complexes. Therefore these results were pooled. One week after treatment the pooled results for the compound action potential showed a small decrease in amplitude, just significant at 2 kHz, but not at 4 and 8 kHz. This decrease disappeared completely after 6 weeks. The pooled results for the negative summating potential (SP) showed a significant increase in magnitude at all frequencies decreasing with post-treatment interval. The cochlear microphonics did not demonstrate any change in amplitude after treatment. The results indicate that deposition of sepharose beads with immune complexes induces endolymphatic hydrops. Also, deposition of the sepharose beads itself may have induced hydrops together with enhancement of the SP. SP enhancement may be related to the development of endolymphatic hydrops rather than to the presence of hydrops as such. This may be based on pressure build-up while hydrops develops.

Action Potentials↗

PubMed1995

Effect of isosorbide on hearing loss due to endolymphatic hydrops.

Changes in hearing were studied in 145 ears (103 patients) with endolymphatic hydrops before and after an 8-week administration of isosorbide. Hearing improvement was observed in 57 (39.3%) of the 145 ears. These improvements showed a significant correlation with positive results in the glycerol test (p < 0.01). Of the 46 ears with a positive result, hearing was improved in 32 (69.6%). Therefore, results of the glycerol test predict a response to isosorbide therapy for the hearing loss of endolymphatic hydrops.

Adolescent↗

PubMedDate not supplied

Studies of cochlear blood flow in guinea pigs with endolymphatic hydrops.

Laser Doppler flowmetry was used to assess cochlear blood flow (CoBF) in guinea pigs with experimental endolymphatic hydrops following intravenous infusion of 5 types of drugs: 50% glycerol, 70% isosorbide, 20% mannitol, 7% sodium bicarbonate, and 1% diphenidol. The magnitude of the CoBF changes following infusion tended to be smaller in the hydropic ears than in the normal control ears. A significant reduction in CoBF changes was observed in hydropic ears infused with isosorbide and sodium bicarbonate. These results suggest that the cochlear microvascular sensitivity to various stimuli such as drug infusion is reduced in hydropic ears. This may result from atrophy of the stria vascularis which is often observed in the hydropic ears of guinea pigs. Thus it seems likely that the same reaction occurs in the inner ear of patients with Ménière's disease in whom atrophy of the stria vascularis is also presumed to exist in conjunction with extensive endolymphatic hydrops. Therefore, it seems probable that the function of the microvasculature of the stria vascularis is impaired in the inner ear of patients with Ménière's disease, resulting in the slow progressive deterioration of the inner ear with time.

Animals↗

PubMed2000

Endolymphatic hydrops induced by chronic administration of vasopressin.

Recently, many lines of evidence have supported the possibilities that vasopressin (VP) is closely linked to the formation of endolymphatic hydrops in Meniere's disease. In the present study, it was examined whether or not the chronic administration of VP might induce endolymphatic hydrops. For this purpose, histological studies and VP radioimmunoassay were independently performed in 20 and 40 guinea pigs, respectively. The degree of hydrops was quantitatively assessed by the increase ratio (IR) of the scala media area in the mid-modiolar sections of the cochlea. The IR was defined by the following equation: 100x(A-B)/B (A: the cross-sectional area of the bulging scala media; B: the no-bulging scala media, enclosed by an idealized straight Reissner's membrane). VP was administered at the rates of 200 microU/kg/min, 400 microU/kg/min and 1000 microU/kg/min for 1 week via the osmotic mini-pump. The IR of the total of the apical, second, third and basal turns (means+/-S.D.s) were 4.4+/-0.7, 10.4+/-1.8, 17.4+/-7.9 (n=10 ears, each) in respective doses of VP. Comparing with that of the control animals (5.2+/-1.7, n=10 ears), the area increased significantly in the VP dosage of 400 and 1000 microU/kg/min (Bonferroni's method, P<0.05). Plasma VP concentrations produced by the VP administration in these dosages were 2.2+/-0.4, 3.5+/-0.8 and 14.0+/-3.9 (n=10, each) pg/ml. Although 3.5 pg/ml is the upper limit of plasma VP concentration in normal human subjects, 14.0 pg/ml was almost the same concentration as those observed in the acute phase of Meniere's disease (Takeda et al., 1995). Therefore, the formation of endolymphatic hydrops in cases of Meniere's disease might be caused by high concentrations of plasma VP.

Analysis of Variance↗

PubMed1983

Endolymphatic subarachnoid shunt operation for idiopathic endolymphatic hydrops.

In 1974 we reported on 92 patients who had endolymphatic subarachnoid shunt surgery for idiopathic endolymphatic hydrops. That group had a follow-up of at least 5 years, and only 41% had satisfactory control of vertigo. The purpose of this paper is to describe the results after a larger postoperative follow-up (12 1/2 years, with a range of 68 to 182 months), and to discuss some additional observations regarding endolymphatic sac operations. Two patients have died of unrelated causes, one in the 115th postoperative month and the other in the 124th postoperative month. Eight patients have been lost to follow-up. Our data show that 35% of the patients have had satisfactory control of their vertigo: 23% have had no vertigo, and 12% have had the vertigo improved by at least 75%. The remaining patients had improvement in vertigo, but not to a satisfactory degree, had pronounced improvement in vertigo, but with subsequent recurrence of severe attacks of dizziness, or had no improvement at all. In addition, there has been a steady deterioration in the success rate with increased time of observation. Nineteen percent of the patients showed significant improvement in hearing after surgery, 47% demonstrated no change in hearing, and 34% had a moderate to profound decline in hearing postoperatively. Of 17 patients who had socially adequate hearing in the afflicted ear preoperatively, 12 showed deterioration in hearing to the point that air-conduction thresholds were below the socially adequate level. Six patients with bilateral endolymphatic hydrops who had almost identical auditory acuity in each ear underwent a unilateral shunt operation. In each of these patients, the unoperated-on ear had better results from the hearing standpoint. The data show, therefore, that control of vertigo with the endolymphatic subarachnoid shunt operation was not only disappointing initially, but as the patients were followed over a longer time, the percentage of patients with satisfactory vertigo control declined. Additionally, one-third of the patients experienced further moderate to profound sensorineural deafness, either as a result of surgery or because the operation failed to control the disease process. Last, it is obvious that the endolymphatic subarachnoid shunt operation did not preserve hearing, even when the operation was performed early in the course of the disease.

Audiometry↗

PubMed1991

Old theme and new reflections: hearing impairment associated with endolymphatic hydrops.

The cause(s) of the hearing impairment associated with Menière's disease are not understood but are undoubtedly associated with the inner ear endolymphatic hydrops. Two major hypotheses have been proposed and widely received: endolymphatic overpressure followed by leaky membranes and subsequently the mixing of high K+ endolymph with perilymph. Our recent data on an experimental model of endolymphatic hydrops have provided grounds for renewed reflections on the pathology. Indeed our data might be interpreted without involving either of the above hypotheses and suggests that the symptoms of Menière's disease might be accounted for by a flow of perilymph from scala vestibuli towards scala tympani with the mixing of the two perilymphs which are similar but not identical in composition. The higher K+ concentration arriving from the scala vestibuli into the scala tympani at the apex of the cochlea via the helicotrema is likely to be toxic to hair cell and auditory nerve fiber function. The mixing of the two perilymphs could result in deterioration of low frequency sensitivity, provoke low frequency tinnitus and in the long term cause spiral ganglion cell degeneration at the apex of the cochlea. The feeling of fullness in the ear might be the result of the decreasing perilymph volume in the scala vestibuli which could give rise to inner ear conductive losses. The patency of the cochlear aqueduct might play a role in determining the high risk group of individuals likely to manifest the symptoms of endolymphatic hydrops.

Ear↗

PubMed1996

The efficacy of tympanic electrocochleography in the diagnosis of endolymphatic hydrops.

Electrocochleography (ECoG), an objective electrophysiologic test, is useful in the clinical diagnosis of endolymphatic hydrops. The purpose of this study was further to define the role of ECoG in the diagnosis of this disease. A retrospective chart review of 100 patients undergoing tympanic ECoG was undertaken comparing symptoms, degree of hearing loss, duration of disease, and diagnosis with ECoG results. The apparent sensitivity and specificity of ECoG in the diagnosis of endolymphatic hydrops were determined to be 57% and 94%, respectively. Three of 30 positive ECoG results were falsely positive. Fluctuating hearing loss and the degree of hearing loss (< 40 dB) and duration of disease (< 48 months) were statistically significant in predicting positive ECoG results. We conclude that a positive ECoG result is helpful in objectively confirming the disease. However, a negative result does not rule out hydrops.

Adult↗

PubMed2002

Vestibular evoked myogenic potentials in patients with contralateral delayed endolymphatic hydrops.

We studied vestibular evoked myogenic potentials (VEMPs) in nine patients with unilateral profound hearing loss followed by contralateral delayed hearing fluctuation and episodic vertigo. This condition has been called contralateral delayed endolymphatic hydrops. Five of nine ears with profound hearing loss (56%) showed an absence of VEMPs. One ear (11%) showed decreased responses, and three ears (33%) had normal responses. Of the ears with fluctuation of hearing, six (67%) showed an absence of responses, and three ears (33%) showed normal responses. In four patients we recorded VEMPs before and after oral administration of glycerol. Three hours after glycerol administration, two of four ears with fluctuating hearing loss showed the appearance of VEMPs although there was an absence of VEMPs before glycerol administration. These results suggested that saccular dysfunction could exist not only in the ears with profound hearing loss but also in ears with fluctuating hearing loss and that saccular endolymphatic hydrops could exist in the ears with fluctuating hearing loss. "Contralateral delayed endolymphatic hydrops" might be an appropriate term.

Aged↗

PubMed2001

Selective vestibular ablation by KTP laser in endolymphatic hydrops.

OBJECTIVES AND HYPOTHESIS: Vertigo, the cause of disability in many patients with Ménière's disease, may be the result of the effects of endolymphatic hydrops on the semicircular canals. We hypothesize that intractable vertigo may be controlled by destruction of the semicircular canal neuroepithelium using visible light lasers without the need for extensive fenestration of the bony labyrinth. This study was designed to assess the cochlear effects of potassium titanyl phosphate (KTP) laser-assisted triple semicircular canal ablation (TSCA) in endolymphatic hydrops. STUDY DESIGN: Randomized, prospective, and controlled. METHODS: Forty-one adult guinea pigs underwent either a unilateral endolymphatic duct occlusion to induce hydrops or a sham procedure. Ten weeks after induction of the hydrops, a KTP laser-assisted TSCA or a sham surgery was performed. RESULTS: Electrocochleographic thresholds to clicks and tone-bursts (2-20 kHz) did not change significantly up to 4 weeks after TSCA in hydropic ears. Cross-sectional histology confirmed the presence of hydrops and the ablation of the semicircular canals. Cochlear whole-mounts for hair cell counts showed no significant loss of outer or inner hair cells in hydropic ears treated with TSCA. CONCLUSION: KTP laser-assisted TSCA can be performed in the guinea pig model of endolymphatic hydrops without significant loss of hearing. Evaluation of this technique may be warranted in patients with intractable Ménière's disease.

Animals↗