Dizziness and Vertigo _________________________________________________________________________
Betahistine is a conservative treatment option widely used in Europe for Ménière disease. It is believed to decrease symp- toms by improving microcirculation in the inner ear and re- balancing endolymph production with resorption [156]. In one study, patients with mixed vestibular etiologies including Ménière disease received betahistine 48 mg/day. The decrease in average vertigo attacks per month from baseline to 60 days on betahistine persisted unchanged at 60 days off betahistine, which may suggest durable vestibular compensation [132]. As mentioned, demonstrating a treatment effect separate from spontaneous remission is difficult in Ménière disease and other s-EVS disorders. Based on clinical experience with long-term treatment in patients with Ménière disease, long-term, high-dose betahistine is the recommended therapy, initiated at 48 mg three times per day [39; 61]. If symptom alleviation is insufficient after three months, the dose can be increased up to 480 mg/day [120; 157]. As noted, betahistine can be obtained at compounding pharmacies in the United States with a prescription [15]. Second Tier Intratympanic injection (ITI) of corticosteroids is suggested for patients with Ménière disease-related disabling vertigo attacks despite conservative treatments, as the complication rates are low and side effects minimal. ITI of 0.4–1.0 mL high-dose dexamethasone solution (12 mg/mL) can improve vertigo symptoms and patient functioning, which may remain durable over 6 to 24 months [120]. However, patients may require repeated injections to maintain efficacy that can wane over time, and intratympanic gentamicin may be more effec- tive [155]. Third Tier Intratympanic gentamicin, a vestibulotoxic antibiotic, is a favored approach for Ménière disease refractory to less invasive options. Gentamicin induces unilateral vestibular loss to facili- tate central compensation, reduce Ménière disease symptoms, and improve overall function [98; 158]. Meta-analyses of pub- lished clinical trials found 92.7% of patients achieved complete or substantial vertigo control and 74.7% achieved complete vertigo control with intratympanic gentamicin [99; 159]. ITI of gentamicin is ototoxic in some patients and has mainly been reserved for patients with Ménière disease and pre-exist- ing hearing loss. To offset this limitation, a newer technique injects a minimal dose of gentamicin (0.5–0.75 mL of a 40 mg/ mL solution) into the middle ear. A single injection provided good vertigo control over four years in 76% of patients; 15% to 20% required a second injection [155].
ITI gentamicin (2.0 mL of 40.0 mg/mL solution; up to two injections) was superior to ITI dexamethasone (4 mg/mL, three injections over seven days) in achieving complete vertigo control (81.0% vs. 43%) and complete or substantial vertigo control (93.5% vs. 61%). Significant hearing loss (>10 dB) developed in 13% of patients taking gentamicin [155; 160]. A 2020 systematic review and meta-analysis compared five treatment arms that included placebo, ITI gentamicin, oral high-dose betahistine, ITI steroid, and ITI steroid plus high- dose betahistine for treatment of Ménière disease [161]. The reviewers found that, among the treatment arms compared, ITI steroid plus high-dose betahistine performed best for both hear- ing preservation and vertigo control. Although ITI gentamicin also performed well, it may be detrimental to hearing preserva- tion with high cumulative dosage and short interval between injections. The authors noted that ITI steroid plus high-dose betahistine has not been compared in head-to-head trials against other interventions, with the exception of ITI steroid alone in one trial, and stated that future trials are needed to establish comparative effectiveness with direct evidence [161]. Intractable Bilateral Ménière Disease Ménière disease may become bilateral in 15% to 20% of patients, usually within the first several years of onset. Bilateral involvement limits some vestibular ablation options, because treating both ears can result in bilateral vestibular loss [15]. Treating one side may not relieve vertigo, and interventional treatment can cause permanent hearing loss in a patient already at risk of hearing loss in both ears [128]. Options for intractable Ménière disease include endolymphatic mastoid shunt procedures, vestibular neurectomy, or labyrin- thectomy, the latter used only in patients already deaf in the affected ear. Ablative surgical procedures are mainly reserved for ITI gentamicin failure. Because the development of Ménière disease is multifactorial, no single approach to therapy is expected to become the standard for all patients [152]. Vestibular Migraine Treatment efficacy for vestibular migraine is not well-studied, partially because the disorder was only defined in 2013 [162]. Established treatments for migraine and/or vertigo are pri- marily recommended as abortive or prophylactic therapies for migraine symptoms in vestibular migraine. These medications may improve both headache and vertigo symptoms but can be hit or miss, and patients may need several different trials to find an individualized therapy [162; 163].
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