In acutely dizzy patients meeting diagnostic criteria for acute vestibular syndrome (AVS), targeted history-taking and testing for subtle oculomotor and vestibular signs is key for distinguishing peripheral (mostly acute vestibular neuropathy) from central (mostly stroke) causes. While performing the HINTS (head-impulse, nystagmus, test of skew) has been shown to have very high diagnostic accuracy for ruling-in and ruling-out stroke, their application may not be feasible (e.g., when training is lacking in non-specialists) or justified (e.g., when no nystagmus is present). As an established clinical test in the emergency-department setting, a graded rating of truncal instability (mild-to-moderate imbalance when walking independently [grade 1]; severe imbalance on standing but unable to walk without support [grade 2]; falling in an upright standing/sitting position [grade 3]) was proposed instead. In a systematic review (n=1810 patients) a moderate sensitivity (69.7% [43.3%–87.9%], low certainty) and a high specificity (83.7% [52.1%–96.0%], low certainty) for grade 2-3 truncal instability to detect a stroke was reported (1). Furthermore, in a retrospective study the value of truncal instability testing in AVS-patients without any nystagmus was assessed. It was found that 14/95 (15%) of their AVS patients did not show any nystagmus; thus the HINTS exam was not applicable in these patients. However, in all these patients they found significant (i.e., grade 2 [n=8] or 3 [n=6]) truncal instability (2). This study supports the use of a formal assessment of gait in AVS patients, especially when no nystagmus is seen and thus the HINTS may be less sensitive and specific.
Key Points:
- In acutely dizzy patients, testing for subtle oculomotor and vestibular signs is essential to distinguish peripheral from central causes.
- Sometimes the HINTS exam (considered the bedside gold standard) may not be feasible (e.g. because of a lack of training) or justified (e.g., because of a lack of nystagmus).
- Performing a graded rating of truncal instability (grade 0-3) instead may provide a valuable alternative.
- Grade 2-3 truncal instability has a moderate sensitivity (67.9%) and a high specificity (83.7%) for detecting a stroke.
- A formal assessment of gait in all acutely dizzy patients is recommended, especially when no nystagmus is seen and thus the HINTS exam may be less sensitive and specific.
References:
- Shah VP, Oliveira J E Silva L, Farah W, Seisa MO, Balla AK, Christensen A, Farah M, Hasan B, Bellolio F, Murad MH. Diagnostic accuracy of the physical examination in emergency department patients with acute vertigo or dizziness: A systematic review and meta-analysis for GRACE-3. Acad Emerg Med. 2022 Dec 1. doi: 10.1111/acem.14630.
- Carmona S, Martínez C, Zalazar G, Koohi N, Kaski D. Acute truncal ataxia without nystagmus in patients with acute vertigo. Eur J Neurol. 2023. doi: 10.1111/ene.15729.
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