xRead - Episodic Vertigo (January 2026)

10976817, 2020, S2, Downloaded from https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599820909438 by Mayo Clinic Libraries, Wiley Online Library on [19/09/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

Basura et al

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described as nonspecific chronic imbalance without discrete vertigo attacks; and there may be other cranial nerve find ings (eg, trigeminal nerve involvement). Two challenges regarding decisions about the use of MRI for asymmetric hearing loss in patients suspected of MD include the follow ing: (1) expert clinicians have only moderate agreement in classifying audiograms as asymmetric or not, 102 and (2) the prevalence of unilateral hearing loss (defined as PTA 25 dB in 1 ear) is 8.9% of the US population aged 20 to 69 years. 103 The primary rationale for early screening for inner ear or retrocochlear lesions is that surgery is more likely to pre serve hearing when the tumor is small as compared with moderate or large lesions. Interestingly, unilateral hearing loss was not associated with reduced health-related QOL in a population-based study. 104 However, the QOL of patients with unilateral SNHL deteriorated particularly with regard to mental functioning to levels similar to those found in patients with bilateral SNHL. 105 In addition, patients are often observed over an extended time even when a schwan noma is identified. The primary disadvantages for early neu roimaging include cost, inconvenience to the patient, false positive results or incidental findings that could result in patient distress, the need for additional testing, and the risk of any procedures (eg, intravenous contrast). Noncontrast MRI has been proposed as a cost-effective means to evalu ate for vestibular schwannoma and other causes of unilateral SNHL. 106-108 Noncontrast examinations can miss small schwannomas or inflammatory processes, 109,110 and post contrast MRI may be of use if the noncontrast examination is discordant with clinical and audiologic findings. 111,112 MRI research is also exploring findings specific to MD. Delayed MRI after IT, intravenous, or trans–eustachian tube contrast delivery allows for differentiation of the endolympha tic and perilymphatic fluid. Much of the recent literature regarding imaging in MD has been in the development of this technique. Currently, there are 5 large (53-74 patients) 113-117 and another 25 smaller case series that evaluated MD patients with delayed postcontrast MRI. 118-142 These data revealed that distention of the endolymphatic space in the cochlea and vestibule (ELH) is commonly identified in patients with definite MD and more frequently than other causes of SNHL or vertigo. However, this finding is not present in all patients with MD, and there remains variability within imaging protocols and proposed grading/assessment systems. 114,133,143-148 Studies employing delayed postcontrast MRI during conservative management 149 following medical therapy, 150-152 IT gentamicin, 153-155 and endolymphatic sac surgery 156-159 in MD patients did not produce imaging char acteristics that correlated with treatment responsiveness or symptomatic improvement. No studies compared findings in the clinically relevant circumstance of clinical uncertainty. Hence, use of imaging to make the diagnosis of MD is still under investigation. As there is no ‘‘gold standard’’ test for MD, results are confounded by efficacies of the interventions as well.

When possible, MRI studies should be interpreted by a board-certified neuroradiologist given the potential subtlety of findings. Patients may be unable to have MRI due to implanted ferromagnetic materials 160 or are unwilling due to claustrophobia or cost. While MRI does not involve irra diation, patients should be aware of the risks of gadolinium based MRI contrast agents, which include (1) rare occur rence of anaphylaxis, (2) the potential development of nephrogenic systemic fibrosis, (3) acute renal failure in patients with preexisting renal insufficiency, 105 and (4) retention of gadolinium-based contrast agents (GBCAs) in patients. 161 To date, no adverse events have been reported from gadolinium retention in the brain. Since 2017, the Food and Drug Administration has required that educational information be provided to each patient before receiving GBCAs. 161,162 ‘‘Health care professionals should consider the retention characteristics of each agent when choosing a GBCA for patients who may be at higher risk for gadoli nium retention. These patients include those requiring multi ple lifetime doses, pregnant women, children, and patients with inflammatory conditions. Minimize repeated GBCA imaging studies when possible, particularly closely spaced MRI studies.’’ 161 STATEMENT 5. VESTIBULAR OR ELECTROPHYSI OLOGIC TESTING: Clinicians should not routinely order vestibular function testing or electrocochleography (ECochG) to establish the diagnosis of Me´nie`re’s disease. Recommendation against based on systematic reviews of cross-sectional studies and observational ECochG studies. Quality improvement opportunity: Avoidance of unnecessary testing. National Quality Strategy domains: Patient Safety, Prevention and Treatment of Leading Causes of Morbidity and Mortality Aggregate evidence quality: Grade B, based on SRs of cross-sectional studies and observational ECochG studies Level of confidence in evidence: Medium, based on difficulty in assessing the quality of the SRs, the meta-analyses, and the subgroups within the cohort Benefits: Avoidance of unnecessary testing, decreased cost, improved efficiency of diagnosis, reduced patient burden of unpleasant testing Risk, harm, cost: Missed or delayed diagnosis of comorbid conditions Benefit-harm assessment: Preponderance of benefit over harms Value judgments: While some of these tests may have a role in individualized patients, MD requires a clinical and audiometric diagnosis. Intentional vagueness: The word routine is used to allow for individualized use of these testing modalities in some of the settings specified in the supporting text. Action Statement Profile: 5