我的头晕病人是卒中吗？-2011

Dizziness is the third most common ma -jor medical symptom reported in gen-eral medical clinics1 and accounts for about 3%–5% of visits across care settings.2 In the United States, this translates to 10 million ambulatory visits per year because of dizziness,3 with roughly 25% of these visits to emergency departments.2 Many patients have transient or episodic symptoms that last seconds, minutes or hours, but some have prolonged dizziness that persists continuously for days to weeks.4 In this article, we use the term “dizziness” to encompass vertigo, presyncope, unsteadi ness, and other nonspecific forms of dizziness. When dizziness de velops acutely, is accompanied by nausea or vomiting, unsteady gait, nystagmus and intolerance to head motion, and persists for a day or more, the clinical condition is known as acute vestibular syndrome.5,6 We define isolated acute vestibular syndrome (with or without hear- ing loss) as occurring in the absence of focal neurologic signs such as hemiparesis, hemi - sensory loss or gaze palsy. Transient dizziness has a differential diagnosis distinct from that of acute vestibular syndrome, and the approach to diagnosis should differ accordingly.7 In this review, we focus on acute vestibular syndrome, whether isolated or not. Most patients with acute vestibular syndrome have an acute, benign, self-limited condition pre- sumed to be viral or postviral. The condition is usually called vestibular neuritis but is some- times referred to as vestibular neuronitis, laby - rinthitis, neurolabyrinthitis or acute peripheral vestibulopathy.5,6 Some authors distinguish be - tween labyrinthitis and vestibular neuritis based on the presence of auditory symptoms at presen- tation;8 however, this distinction is inconsistently applied, and the terms are often used inter- changeably. In this article, we include labyrinth - itis and vestibular neuritis together as peripheral causes of acute vestibular syndrome — that is, pathology localized to the inner ear (labyrinth) or eighth cranial (vestibular) nerve — as distin- guished from central causes affecting vestibular connections in the central nervous system. Al - though peripheral causes are more common, dangerous central causes, particularly ischemic stroke in the brainstem or cerebellum, can mimic benign peripheral causes closely.6,9–13 The evidence base for diagnosing the cause of dizziness is limited.14 There is growing evidence that the cause of acute vestibular syndrome is mis- diagnosed in many patients15–19 and that frontline physicians are eager for diagnostic guidelines.20,21 Regional variation in diagnostic practice is proba- bly common,3 but little is known about factors influencing diagnostic accuracy (e.g., access to technology, availability of consultants, nature of training, cultural or linguistic differences). Narrative reviews have highlighted the im - portance of accurately assessing the risk of dan- gerous disorders, particularly ischemic stroke in the posterior fossa, and have emphasized the util- ity of a focused history and physical examination in these patients.5,22–24 However, we are un aware of any systematic re views, practice parameters or fully validated clinical decision rules applicable to unselected patients with acute, prolonged dizziness that offer evidence-based guidance for the diagnosis and management of acute vestibular syndrome. We therefore performed a systematic review and synthesis of the medical literature, focusing on bedside diagnostic predictors. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome Alexander A. Tarnutzer MD, Aaron L. Berkowitz MD PhD, Karen A. Robinson PhD, Yu-Hsiang Hsieh PhD, David E. Newman-Toker MD PhD Competing interests: None declared. This article has been peer reviewed. Correspondence to: Dr. David E. Newman-Toker, toker@jhu.edu CMAJ 2011. DOI:10.1503 /cmaj.100174 ReviewCMAJ • The most common causes of acute vestibular syndrome are vestibular neuritis (often called labyrinthitis) and ischemic stroke in the brainstem or cerebellum. • Vertebrobasilar ischemic stroke may closely mimic peripheral vestibular disorders, with obvious focal neurologic signs absent in more than half of people presenting with acute vestibular syndrome due to stroke. • Computed tomography has poor sensitivity in acute stroke, and diffusion-weighted magnetic resonance imaging (MRI) misses up to one in five strokes in the posterior fossa in the first 24–48 hours. • Expert opinion suggests a combination of focused history and physical examination as the initial approach to evaluating whether acute vestibular syndrome is due to stroke. • A three-component bedside oculomotor examination — HINTS (horizontal head impulse test, nystagmus and test of skew) — identifies stroke with high sensitivity and specificity in patients with acute vestibular syndrome and rules out stroke more effectively than early diffusion-weighted MRI. Key points © 2011 Canadian Medical Association or its licensors CMAJ, June 14, 2011, 183(9) E571 Literature review and analysis Details of the search strategy appear in Appendix 1. In brief, we searched MEDLINE to identify English- language observational studies on the clin- ical features, diagnostic evaluation and differential diagnosis of acute vestibular syndrome published through Dec. 4, 2009. We also performed a man- ual search of the bibliographies of eligible articles. Titles and abstracts of identified articles were screened independently by two reviewers (A.A.T. and A.L.B.). Articles were excluded if they lacked original patient data, offered no symptom data about dizziness, provided no information about diagnostic accuracy for acute central or peripheral vestibulopathies, did not evaluate patients in the acute stage of disease, involved patients under age 18 years or re ported on fewer than five patients. Full-text versions of eligible articles were re viewed independently by the same two reviewers. A third reviewer (D.N.- T.) verified the eligibility of selected articles and settled any discrepancies. One unmasked rater (A.A.T.) assessed the strength of the reference standards used in the included studies to distinguish between a peripheral and a central cause of acute vestibular syndrome. A second unmasked rater (D.N.-T.) verified the strength of the reference standard. (Definitions of the criteria used to assess the strength of the refer- ence standards appear in Appendix 1.) Information abstracted from each article included study type, number of patients with dizzi- ness, inclusion criteria and study site. Also ex - tracted were data on the diagnostic tests used and the proportion of patients with positive or negative test results. Where appropriate, we attempted to contact authors regarding study details. For each test that was used in two or more stud- ies, we calculated the pooled sensitivity, speci- ficity, and positive and negative likelihood ratios (and 95% confidence intervals [CIs]) for the test.25 No formal tests of heterogeneity were applied, but we conducted a prospectively de fined subgroup analysis that compared findings in stroke patients who had an infarction in the territory of the ante- rior inferior cerebellar artery with findings in those who had cerebellar infarctions in other vascular territories (posterior in ferior cerebellar artery or superior cerebellar artery). All p values were two- sided, with significance set at p < 0.05. In instances where evidence derived from our systematic review was incomplete, we included expert opinion and critically reviewed related evidence to support or refute such opinion. Evi- dence failing to meet strict inclusion criteria was considered part of the critical review. Details of the results of our literature search appear in Appendix 1 and Figure 1. Our system- atic search identified 779 unique citations. We re viewed 139 full-text articles and their bibli- ographies and found 27 articles reporting data from 21 studies that met the inclusion criteria. Review E572 CMAJ, June 14, 2011, 183(9) Excluded n = 12 • No medium- or high-quality reference standard used to rule in or rule out stroke† Excluded n = 640 • Not in English n = 2 • Lacked original patient data n = 151 • No symptom data about dizziness n = 113 • No information about diagnostic accuracy for acute central or peripheral vestibulopathies n = 67 • Patients not evaluated in acute stage of disease n = 172 • Included fewer than five patients n = 135 Citations identified through search of MEDLINE database n = 779 Excluded n = 117 • No information about diagnostic accuracy for acute central or peripheral vestibulopathies n = 59 • Patients not evaluated in acute stage of disease n = 36 • No symptom data about dizziness n = 11 • Patients aged < 18 years n = 6 • Article could not be retrieved n = 3 • Included fewer than five patients n = 2 Articles identified for full-text review n = 139 Articles included in the systematic review n = 15 (10 studies) Articles identified through review of bibliographies of selected articles n = 5 Satisfied inclusion criteria n = 22 Articles considered for systematic review n = 27 (21 studies*) Figure 1: Flow diagram indicating selection of articles. *In two articles26,27 (n = 108), published by a single research group, it is unclear whether each article reports on an entirely distinct or partially overlapping group of patients (see Table 1 for details). There could be as many as 28 patients counted more than once. †The criteria used to assess the strength of the reference standards used to rule in or rule out stroke appear in Appendix 1. We excluded 12 articles reporting data from 11 studies because of inadequate diagnostic refer- ence standards, which left 10 studies describing a total of 392 patients. Details of these studies appear in Table 1. How common is acute vestibular syndrome? We found no direct studies of the incidence of acute vestibular syndrome as a clinical presenta- tion. Vestibular neuritis, probably the most com- mon cause of acute vestibular syndrome, has an estimated annual incidence of 3.5 per 100 000 population based on a single retrospective survey of neuro-otology clinics in Japan.36 Data from a nationally representative sample of emergency departments in the United States indicate that, of 2.6 million visits annually because of dizziness, acute vestibular syndrome from a peripheral cause (i.e., vestibular neuritis or labyrinthitis) is diagnosed in 6% of patients, which corresponds to about 150 000 visits each year.2,18 Another 4% of patients receive a cerebrovascular diagnosis, and 22% leave the emergency department with- out a causal diagnosis (i.e., they receive a diag- nosis of “dizziness or vertigo”),2,18 many of whom probably presented with acute vestibular syndrome. From a survey of the general popula- tion in Germany, 11% of those who reported dizziness indicated that the symptom had lasted for more than a day.4 In a US-based study in - volving consecutive patients who visited an emergency department because of dizziness,37 27% (47/175) of those who had any dizziness in the 24 hours before their visit still had dizziness in the emergency department that had not remit- ted since it began (unpublished data). Thus, we estimate that about 10% to 20% of patients who present with acute dizziness to the emergency department have acute vestibular syndrome, which corresponds to about 250 000 to 500 000 visits to an emergency department each year in the United States alone. What are the most common causes? In our systematic review, we found no studies of all presentations of acute vestibular syndrome. Only three studies enrolled relatively unselected, consecutive populations.6,9,11 Vestibular neuritis was the most common peripheral cause of acute ves tibular syndrome, and there were no patients with labrynthitis (i.e., peripheral cause of acute vestibular syndrome with auditory symptoms) reported in these studies. However, two studies expressly excluded patients with auditory symp- toms,9,11 and the third excluded patients with a history of recurrent auditory symptoms.6 The most common central causes of acute vestibular syndrome reported in these three studies are listed in Table 2. Central causes mim- icking vestibular neuritis (sometimes called “pseudoneuritis”11) were predominantly cere- brovascular (83%) and demyelinating conditions (11%). Two studies prospectively en rolled pa - tients at high risk for stroke using age or vascular risk factors as entry criteria,6,9 which probably led to overrepresentation of cerebro vascular pa - tients; the third study used a case–control design and did not report the method for sampling pa - tients in the control group.11 The remaining seven studies included in the systematic review fo - cused only on patients with acute dizziness who had a diagnosis of stroke.10,26−28,31−33 None of the included studies was large enough to identify rare but important causes such as Wernicke syndrome,38 bacterial laby - rinthitis39 or brainstem encephalitis.40 Box 1 shows a suggested differential diagnosis for acute vestibular syndrome adapted from narra- tive reviews written by specialists in the field of vestibular disorders.8,24 Findings from our systematic review do not allow a definitive statement about the relative prevalence of vestibular neuritis versus stroke among unselected patients presenting with acute vestibular syndrome. We can, however, roughly estimate the proportion of patients presenting with acute vestibular syndrome who have stroke, using data on the annual incidence of stroke and prevalence of dizziness among stroke patients. Of 795 000 strokes per year in the United States,45 about 18% are located in the posterior fossa,46 and about 50%–70% are associated with dizziness as a prominent or presenting symp- tom.22,47 Thus, we estimate that there are about 70 000 to 100 000 strokes per year in the United States with dizziness as a prominent or present- ing symptom. Considering the approximate inci- dence of acute vestibular syndrome calculated earlier (about 250 000 to 500 000 per year in the United States), we estimate the true proportion of acute vestibular syndrome due to stroke to be about 25% ± 15%. What elements of clinical history are useful for diagnosis? Certain clinical findings from history-taking help to distinguish between stroke and vestibular neu- ritis in patients presenting with acute vestibular Review CMAJ, June 14, 2011, 183(9) E573 Review E574 CMAJ, June 14, 2011, 183(9) Table 1: Characteristics of studies included in the systematic review of bedside diagnostic predictors of stroke in patients with acute vestibular syndrome (AVS) Study No. of patients screened (no. included in study) Study population (study focus) Study site Diagnostic reference standards Strength of reference standard to rule in/rule out stroke* Study design Comments Rubenstein et al.28 7 (7) AVS and diagnosis of cerebellar stroke or hemorrhage (clinical findings) NR • CT (all patients) Medium/NA Retrospective case series Clinical evaluation delayed relative to onset of symptoms up to 7 d. Norrving et al.9 (preliminary report in Magnusson et al.29,30) 24 (24) AVS for > 48 h and age 50–75 yr (clinical findings and electro- oculography) ED/HA • MRI without DWI (n = 22) • CT (n = 2) Medium/ Medium Prospective cross-sectional study (consecutive cases) Only 4 patients had CT in acute phase; MRI was performed 14– 44 d after onset of symptoms. Patients with brainstem/ cerebellar dysfunction other than nystagmus were excluded. Kim et al.31 30 (30) Acute isolated vertigo and diagnosis of stroke (clinical findings) ED/HA • MRI without DWI (n = 17) • CT (n = 13) Medium/NA Prospective case series (possibly consecutive) CT obtained in all patients. MRI obtained in those with initially negative CT. Chen et al.32 295 (7) Acute vertigo and diagnosis of brainstem stroke (clinical findings, caloric testing and vestibular-evoked myogenic potentials) ED/HA • MRI without DWI (all patients) Medium/NA Retrospective case series (possibly consecutive) Unclear whether patients with cerebellar infarctions were considered or included. Lee et al.26† 28 (28) Acute audiovestibular loss and diagnosis of vertebrobasilar infarction (clinical findings and audiometric assessment) ED/HA • MRI with DWI (all patients) High/NA Prospective case series (consecutive) Retrospective analysis of data from a prospective stroke registry. Lee et al.10 25 (25) AVS and diagnosis of cerebellar infarction (clinical findings and audiovestibular testing, vascular territory) ED/HA • MRI with DWI, and MRA (all patients) High/NA Prospective case series (consecutive) Patients with brainstem/ cerebellar dysfunction other than nystagmus were excluded. Retrospective analysis of data from a prospective stroke registry. Cnyrim et al.11 NR (83) AVS and diagnosis of vestibular neuritis or pseudoneuritis (diagnosis, clinical features) ED • MRI with DWI (all patients) High/Medium Case–control study (possibly prospective, possibly consecutive) Initial MRI obtained within 5 d of symptom onset; no further breakdown provided. No follow- up MRI or clinical follow-up in patients with initially negative MRI. Patients with hearing loss or brainstem/cerebellar dysfunction other than nystagmus were excluded. Retrospective data analysis. Selection of controls not described. Moon et al.33 7 (7) Acute vertigo and diagnosis of isolated infarction of the cerebellar nodulus (clinical features, audiovestibular findings) ED/HA • MRI with DWI, and MRA (all patients) High/NA Retrospective case series One of 8 patients reported had a transient positional vertigo syndrome rather than AVS. Kattah et al.6 (preliminary report in Newman-Toker et al.12) 121 (101) AVS and ≥ 1 risk factor for stroke (diagnosis, clinical features, imaging) ED/HA • MRI with DWI (all patients) High/High Prospective cross-sectional study (consecutive cases) Patients with initially negative MRI underwent repeat MRI owing to unexplained signs suggesting central location. Lee et al.27† (preliminary report in Lee et al.34 and Lee and Cho35) 80 (80) AVS and AICA stroke (audio-vestibular findings, topography of lesion) ED/HA • MRI with DWI, and MRA (all patients) High/NA Prospective case series (consecutive) Retrospective analysis of data from prospective stroke registry. Most MRIs obtained within 30 d after symptom onset. Note: AICA = anterior inferior cerebellar artery, AVS = acute vestibular syndrome, CT = computed tomography, DWI = diffusion-weighted imaging, ED = emergency department, HA = hospital admission, MRA = magnetic resonance angiography, MRI = magnetic resonance imaging, NA = not applicable, NR = not reported. *The strength of the reference standard used to rule stroke in or out was rated as high, medium or low (criteria are defined in Appendix 1). †In these two studies,26,27 published by a single research group and focused on AVS with hearing loss and AICA stroke, it is unclear whether they report on entirely distinct or partially overlapping groups of patients. In the 2009 study,27 the authors state that 23 patients were reported on previously; they cite several prior studies (including the 2002 manuscript34) but do not include their 2005 manuscript26 in the list of related publications. Accordingly, we have included this 2005 article as representing a separate study, rather than as a preliminary report of the later manuscript. However, the 28 patients reported in the 2005 study were from the same university-based stroke registry reported by the au