Endolymphatic hydrops: can it be controlled?

The role of serum osmolality in Meniere's disease with acute sensorineural hearing loss

OBJECTIVE

This study investigated the role of serum osmolality in Meniere's disease (MD) patients with acute sensorineural hearing loss (SNHL).

DESIGN

Retrospective study.

STUDY SAMPLES

Twenty definite MD patients with acute unilateral SNHL were treated with an osmotic diuretic (Isosorbide, 100 mL daily) and assigned to Group A. Another 20 age- and sex-matched definite MD patients with acute SNHL were not given Isosorbide and assigned to Group B. Both groups underwent audiometry and blood examination for serum osmolality before and after treatment.

RESULTS

Group A revealed a significant increase in serum osmolality after treatment. The optimal cut-off values for increased serum osmolality in Group A were +1.5 mOSM/L for predicting hearing improvement at frequencies of 250-1000 Hz, and +2.5 mOSM/L at 2000-4000 Hz. Comparing increased levels of serum osmolality (> +2.0 vs. ≤ +2.0 mOSM/L), Isosorbide dosing at 3.0 L vs. 1.0 L, significantly differed in the odds ratio (OR). Isosorbide at a total dosage of 3.0 L thus improves the hearing threshold by >10 dB at frequencies of 250-2000 Hz.

CONCLUSION

The Isosorbide at a total dosage of 3.0 L may increase serum osmolality by > +2.0 mOSM/L, and improve the hearing threshold for hydropic ears at least >10 dB at low- and mid-frequencies.

Clinical, oculographic and vestibular test characteristics of Ménière's disease

Seventy Ménière's disease (MD) patients with spontaneous vertigo (100%), unilateral aural fullness (57.1%), tinnitus (78.6%), and subjective hearing loss (75.7%) self-recorded nystagmus during their episodes of vertigo using portable video oculography goggles. All demonstrated ictal spontaneous nystagmus, horizontal in 94.3% (n = 66) and vertical in 5.7% (n = 4), with a mean slow-phase velocity (SPV) of 42.8 ± 31.1°/s (range 5.3-160.1). Direction reversal of spontaneous horizontal nystagmus was captured in 58.6%, within the same episode in 34.3%, and over different days in 24.3%. In 18.6%, we observed ipsiversive then contraversive nystagmus, and in 12.9% contraversive to ipsiversive direction reversal. Ictal nystagmus SPV (42.8 ± 31.1°/s) was significantly faster than interictal (1.4 ± 3.1°/s, p < 0.001, CI 34.277-48.776). Compared to age-matched healthy controls, interictal video head impulse test gains in MD ears were significantly lower, cumulative and first saccade (S1) amplitudes were significantly larger, and S1 peak velocities were significantly faster (p = 0.038/0.019/0.008/ < 0.001, CI 0.002-0.071/0.130-1.444/0.138-0.909/14.614-41.506). Audiometry showed asymmetrically increased thresholds in 100% of MD ears (n = 70). Significant caloric, air-conducted (AC) cervical vestibular-evoked myogenic potential (VEMP), and AC ocular VEMP asymmetries were found in 61.4, 37.9, and 44.4% of patients (MD ear reduced). Transtympanic electrocochleography tested in 36 ears (23 patients) showed 81.8% of MD ears had a positive result for hydrops (either a summating potential at 1/2 kHz < - 6 µV, or an SP/AP ratio > 40%). Using ictal nystagmus findings of SPV > 12°/s, and a caloric canal paresis > 25%, we correctly separated a diagnosis MD from Vestibular Migraine with a sensitivity and specificity of 95.7% and 85.1% (CI 0.89-0.97).

Can vestibular-evoked myogenic potentials help differentiate Ménière disease from vestibular migraine?

OBJECTIVES

To characterize both cervical and ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) responses to air-conducted sound (ACS) and midline taps in Ménière disease (MD), vestibular migraine (VM), and controls, as well as to determine if cVEMP or oVEMP responses can differentiate MD from VM.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Unilateral definite MD patients (n = 20), VM patients (n = 21) by modified Neuhauser criteria, and age-matched controls (n = 28). cVEMP testing used ACS (clicks), and oVEMP testing used ACS (clicks and 500-Hz tone bursts) and midline tap stimuli (reflex hammer and Mini-Shaker). Outcome parameters were cVEMP peak-to-peak amplitudes and oVEMP n10 amplitudes.

RESULTS

Relative to controls, MD and VM groups both showed reduced click-evoked cVEMP (P < .001) and oVEMP (P < .001) amplitudes. Only the MD group showed reduction in tone-evoked amplitudes for oVEMP. Tone-evoked oVEMPs differentiated MD from controls (P = .001) and from VM (P = .007). The oVEMPs in response to the reflex hammer and Mini-Shaker midline taps showed no differences between groups (P > .210).

CONCLUSIONS

Using these techniques, VM and MD behaved similarly on most of the VEMP test battery. A link in their pathophysiology may be responsible for these responses. The data suggest a difference in 500-Hz tone burst-evoked oVEMP responses between MD and MV as a group. However, no VEMP test that was investigated segregated individuals with MD from those with VM.

Audiovestibular testing in patients with Meniere's disease

In this article, the present state of the art with respect to audiovestibular testing for Meniere's disease (MD) is reviewed. There is no gold standard for MD diagnosis, and the classic dictum is that even the "best" tests yield positive results in only two-thirds of patients with MD. Still, we advocate the use and further investigation of advanced audiovestibular testing in patients with MD in an attempt to answer the questions that confront any clinician who cares for patients with audiovestibular symptoms.

Physiologic effects on the vestibular system in Meniere's disease

Ménière syndrome is an inner ear disorder characterized by spontaneous attacks of vertigo, fluctuating low-frequency sensorineural hearing loss, aural fullness and tinnitus. When the syndrome is idiopathic and cannot be attributed to any other cause (eg, syphilis, immune-mediated inner ear disease, surgical trauma), it is referred to as Ménière disease. This article reviews the physiologic effects of Ménière disease on vestibular function, as measured by caloric, head impulse, and vestibular-evoked myogenic potential testing.

M??ni??re??s disease

PURPOSE OF REVIEW

Ménière's disease is characterized by spontaneous attacks of vertigo, fluctuating sensorineural hearing loss, aural fullness, and tinnitus. The pathologic process involves distortion of the membranous labyrinth with the formation of endolymphatic hydrops. This review describes the pathogenesis and etiology as well as the diagnosis and treatment of Ménière's disease.

RECENT FINDINGS

Initial management of Ménière's disease can involve a low-salt diet and a diuretic. Treatment with intratympanic injection of gentamicin can be beneficial when vertigo persists despite optimal medical management. Recent studies have shown that gentamicin reduces vestibular function in the treated ear, although complete ablation of this vestibular function is not typically required in order to achieve control of vertigo.

SUMMARY

Vertigo is often the most debilitating symptom associated with Ménière's disease. Many treatment options exist for the management of vertigo. Intratympanic injection of gentamicin (low dose) can be used in patients for whom vertigo has not been controlled by medical measures. Ongoing research is providing a greater understanding of the effects of gentamicin on vestibular function and of the mechanisms through which gentamicin leads to control of vertigo.

Endolymphatic Mastoid Shunt Surgery in Unilateral Meniere's Disease

One-hundred endolymphatic mastoid shunt operations in patients with classic unilateral Meniere's disease were analyzed. The patients were carefully preselected with a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definitive electrophysiologic evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analyzed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AAOO, 1972), and the more recent modifications of the American Academy of Otolaryngology— Head and Neck Surgery (AA-HNS, 1985). Control of vertigo was achieved in 79% of the patients overall, with 42% sustaining complete control and 37% substantial control. A significant hearing improvement was obtained in 15% of cases, there was no change in 56% of patients, and hearing became worse in 29%. Tinnitus improved following surgery in 35% of patients, was the same in 56%, and worse in 9%. Postoperatively, there was no disability in 42% of the patients, some degree of disability in 50%, and severe disability and inability to sustain gainful employment in only 8%.

Endolymphatic sac surgery: analysis of 100 operations

One hundred endolymphatic mastoid shunt operations in 89 patients with classical Menière's disease were analysed. The disease was bilateral in 18 patients (20%). The patients were carefully pre-selected by a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definite electrophysiological evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analysed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AA00, 1972) and the more recent modifications of the American Academy of Otolaryngology, Head and Neck Surgery (AA-HNS, 1985). Control of the vertigo was achieved in 81% of the patients overall, in 88% of the patients with unilateral disease and in 63% of the patients with bilateral disease. A significant hearing improvement was obtained in 19% of patients, no change in 55% and hearing became worse in 26%. Tinnitus improved in 38% of patients, was unchanged in 52% and became worse in 10%. Disability was assessed and there was no disability in 44% of the patients post-operatively, some degree of disability in 48% but only 8% were severely disabled and unable to sustain gainful employment.

Role and results of cortical mastoidectomy and endolymphatic sac surgery in Menière's disease

It is almost impossible to establish the natural history of Menière's disease and, by the same token, it is difficult to confirm the efficacy of endolymphatic sac surgery. The authors doubt the logic of sac operations. Only two controlled trials of sac surgery have been found and both cast doubt upon its value. There do not appear to be any controlled trials indicating that it works. In 14 cases of incapacitating Menière's disease, where vestibular nerve section was indicated, cortical mastoidectomy was offered and accepted in the expectation that two-thirds might be spared the more major procedure. In the event, the vertigo was controlled in eight out of 14 (57 per cent), the remaining six (43 per cent) requiring more major surgery. A surgical model illustrates that, of themselves, these results are essentially meaningless in assessing the efficacy of cortical mastoidectomy in Menière's disease. Until all cases in a community are considered and followed-up, we shall be in doubt about the value of sac surgery and most other treatments of Menière's disease.