Published Ahead of Print on July 15, 2015 as 10.1212/WNL.0000000000001830

Acute stroke chameleons in a university hospital Risk factors, circumstances, and outcomes

Benjamin Richoz, MD Olivier Hugli, MD, MSc Fabrice Dami, MD Pierre-Nicolas Carron, MD Mohamed Faouzi, PhD Patrik Michel, MD

Correspondence to Dr. Richoz: [email protected]

ABSTRACT

Objective: To identify risk factors, circumstances, and outcomes for individuals with acute ischemic stroke (AIS) chameleons (AIS-C) arriving in the emergency department of a university hospital.

Methods: We retrospectively reviewed all patients with AIS from the prospectively constructed Acute Stroke Registry and Analysis of Lausanne during 8.25 years. AIS-C were defined as a failure to suspect stroke or as incorrect exclusion of stroke diagnosis. They were compared with patients diagnosed correctly at the time of admission.

Results: Forty-seven of 2,200 AIS were missed (2.1%). These AIS-C were either very mild or very severe strokes. Multivariate analysis showed a younger age in patients with AIS-C (odds ratio [OR] per year 0.98, p , 0.01), less prestroke statin treatment (OR 0.29, p 5 0.04), and lower diastolic admission blood pressure (OR 0.98 p 5 0.04). They showed less eye deviation (OR 0.21, p 5 0.04) and more cerebellar strokes (OR 3.78, p , 0.01). AIS-C were misdiagnosed as other neurologic (42.6% of cases) or nonneurologic (17.0%) disease, as unexplained decreased level of consciousness (21.3%), and as concomitantly present disease (19.1%). At 12 months, patients with AIS-C had less favorable outcomes (adjusted OR 0.21, p , 0.01) and higher mortality (adjusted OR 4.37, p , 0.01). Conclusions: AIS are missed in patients with younger age with a lower cerebrovascular risk profile and may be masked by other acute conditions. Patients with chameleons present more often with milder strokes or coma, fewer focal signs and cerebellar strokes, and have higher disability and mortality rates at 12 months. These findings may be used to raise awareness in emergency departments to recognize and treat such patients appropriately. Neurology® 2015;85:1–7 GLOSSARY AIS 5 acute ischemic stroke; AIS-C 5 acute ischemic stroke chameleon; ASTRAL 5 Acute Stroke Registry and Analysis of Lausanne; ED 5 emergency department; NIHSS 5 NIH Stroke Scale; OR 5 odds ratio.

In the emergency department (ED) setting, failure to diagnose a significant disease such as an acute ischemic stroke (AIS) may harm the patient.1 Data on AIS mistaken as other medical problems (“stroke chameleon,” AIS-C) are still sparse. In a recent publication, altered mental status, syncope, hypertensive emergency, and systemic infection were the most frequent erroneous diagnoses.2 Patients with central vestibular syndromes from cerebellar or brainstem stroke are at particular risk for misdiagnosis.3–6 AIS presenting as pure cognitive alterations, such as confusional state or Wernicke aphasia, may be attributed to metabolic disturbances or migraine.7 Also, emotional changes accompanying a stroke may lead to a diagnosis of psychogenic disease.8 Other risk factors for missing a stroke may be the absence of focal neurologic deficit, young age with few cerebrovascular risk factors, and unavailability of neurologic expertise.9 Inappropriate diagnostic testing or inadequate interpretation of neuroimaging may also contribute to missing a stroke.10 Furthermore, relying on MRI diffusion-weighted imaging may not be sufficient to rule out a stroke.11,12 Given the paucity of systematically collected data on AIS-C, we aimed to identify demographic and clinical predictors of prospectively collected AIS-C in the ED of a tertiary care Supplemental data at Neurology.org From the Neurology Department (B.R., P.M.), Emergency Department (O.H., F.D., P.-N.C.), and Institute of Social and Preventive Medicine (M.F.), Centre Hospitalier Universitaire Vaudois and University of Lausanne, Switzerland. Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article. © 2015 American Academy of Neurology

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hospital and stroke center. Secondary goals were to calculate the rate of AIS-C and to identify typical stroke syndromes and circumstances of undiagnosed stroke. Finally, we aimed to assess the clinical outcomes and stroke recurrence rates of these patients compared with patients with correctly diagnosed AIS.

this diagnosis by the subsequent neurologic consultation. The identification of stroke in chameleons was made by boardcertified neurologists based on the clinical course and reassessment and/or by appropriate neuroimaging. Systematic diffusion-weighted MRI is not performed in all patients with new neurologic disease in our ED. Data collection in ASTRAL includes demographics (age, sex, insurance type), vascular risk factors (such as arterial hypertension, atrial fibrillation, diabetes mellitus, valve replacements, coronary artery disease, and smoking), and previous cerebrovascular events.13 Onset-to-hospital delay, prestroke Rankin score, and medications at the time of stroke are routinely collected. Stroke mechanism is classified according to TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria15 with dissection and multiple causes added as additional mechanisms. Metabolic variables (serum glucose, creatinine, cholesterol, hemoglobin) and vital signs (temperature, heart rate, systolic and diastolic blood pressure) are recorded on arrival in the ED. Focal neurologic signs or symptoms are noted, and the NIH Stroke Scale (NIHSS) is performed or supervised on admission by NIHSS-certified personnel when stroke is suspected. In patients with AIS-C, NIHSS was reconstructed from the clinical notes, a method shown to be reliable.16 Rates of thrombolysis and acute endovascular treatment were calculated for the AIS-C and AIS groups. In addition to data from ASTRAL, we retrospectively reviewed the medical charts of all patients with AIS-C for the following additional information: the erroneous initial diagnosis,

METHODS We retrospectively reviewed all patients with AIS from January 1, 2003, to March 31, 2011, from the prospectively constructed Acute Stroke Registry and Analysis of Lausanne (ASTRAL), which collects data of all AIS patients admitted to the stroke unit and/or intensive care unit of a university hospital (Centre Hospitalier Universitaire Vaudois) within 24 hours of the last known well time.13 In our center, patients with suspected acute stroke who are not thrombolysis candidates or with other acute neurologic symptoms are usually evaluated first by ED physicians, who then call the neurology resident or board-eligible senior registrar available 24 hours/24 hours for evaluation of suspected stroke or of other explained or unexplained neurologic problems. A final diagnosis of stroke is made according to the World Health Organization definition14 by board-certified academic neurologists with cerebrovascular expertise, regardless of whether infarction was evident on cerebral imaging or not. AIS-C were defined as a failure to suspect a stroke by the ED physician or an incorrect exclusion of

Table 1

Patient characteristics

Variable

Overall population

AIS-C

AIS

Missing data

No. (%)

2,200

47 (2.1)

2,153 (97.9)



Male, n (%)

1,233 (56.2)

31 (66.0)

1,202 (56.0)

6

Age, y (IQR)

72.6 (21.1)

64.5 (28.3)

72.8 (21.1)

NIHSS at admission, points (IQR)

6 (11)

3 (8)

6 (11)

Prestroke Rankin Scale (IQR)

0 (1)

0 (2)

0 (1)

OR (95% CI)

p Value





Clinical features 0.66 (0.36–1.21)

0.18

1

0.97 (0.97–0.99)

,0.01

16

0.97 (0.93–1.02)

0.21

33

1.09 (0.83–1.44)

0.52

Cerebrovascular risk factors, n (%) Hypertension

1,489 (67.9)

22 (47.8)

1,467 (68.3)

7

0.42 (0.24–0.76)

,0.01

Diabetes

3,828 (17.5)

7 (15.2)

375 (17.6)

17

0.84 (0.37–1.90)

0.68

Cholesterol

1,501 (68.5)

29 (63.0)

1,472 (68.7)

10

0.78 (0.43–1.43)

0.42

Smoking

515 (23.7)

16 (37.2)

499 (23.5)

29

1.84 (1.01–3.33)

0.046

Atrial fibrillation

597 (26.7)

13 (28.9)

574 (26.7)

5

1.12 (0.58–2.14)

0.74

Eye deviation, n (%)

446 (20.6)

2 (4.4)

444 (21.0)

36

0.17 (0.04–0.71)

0.01

Paresis, n (%)

1,693 (77.6)

30 (63.8)

1,663 (78.0)

19

0.50 (0.27–0.91)

0.02

Sensory deficit, n (%)

1,085 (50.1)

16 (34.8)

1,069 (50.5)

36

0.52 (0.28–0.97)

0.04

Bilateral stroke, n (%)

198 (9.1)

11 (23.4)

187 (8.7)

33

3.19 (1.60–6.37)

,0.01

Delay stroke onset to ED arrival, min (IQR)

223 (581)

224 (579)

52

0.99 (0.95–1.04)

0.77

Stroke characteristic

191 (588)

a

TOAST mechanism, n (%) Atherosclerotic

292 (13.5)

3 (6.7)

289 (13.6)

35

0.45 (0.14–1.47)

0.19

Cardiac

745 (34.4)

22 (48.9)

723 (34.1)

35

1.85 (1.02–3.34)

0.04

Lacunar

313 (14.5)

3 (6.7)

310 (14.6)

35

0.42 (0.13–1.35)

0.15

Abbreviations: AIS 5 acute ischemic stroke; AIS-C 5 acute ischemic stroke chameleon; CI 5 confidence interval; ED 5 emergency department; IQR 5 interquartile range; NIHSS 5 NIH Stroke Scale; OR 5 odds ratio. a Trial of Org 10172 in Acute Stroke Treatment; further variables, as well as unknown and multiple causes of strokes are listed in table e-1. 2

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the specialty of the physician(s) who missed the diagnosis, and the modalities by which the correct diagnosis was eventually made. The initial neuroradiologic workup for suspected AIS in our center is mostly an immediate head CT including cervical and cerebral angiography and perfusion CT.13 Repeat tissue and arterial imaging by MRI or CT is performed in the subacute phase if considered clinically necessary. For patients with new neurologic symptoms in whom AIS is not part of the initial differential diagnosis, the decision to perform, the timing, and the type of

Figure 1

Age and NIHSS distribution

neuroimaging is made on an individual basis by the emergency room physician who usually follows the neurologic consultant’s recommendation (if a neurologic consultation is requested). Rankin score and recurrence of ischemic cerebrovascular events (ischemic stroke and TIA) were assessed in a structured telephone interview at 12 months by Rankin-certified medical personnel. Outcome was considered favorable if the modified Rankin Scale score was #2. Results are expressed as medians and interquartile range for continuous variables or absolute counts and percentages for categorical variables unless stated otherwise. For the identification of risk factors associated with AIS-C, patients in whom acute stroke was initially missed in the ED were compared with patients in whom AIS was correctly diagnosed. Missing data that were not retrievable retrospectively were omitted from the statistical analysis and are reported in respective tables or in the Results section. Bivariate associations between each factor and the outcome were analyzed using a logistic regression model, and the strength of the association was evaluated by the odds ratio. Significant predictors from the bivariate analysis (p , 0.05) were used to fit a multivariate logistic model to determine independent predictors. Probability values ,0.05 were considered significant. Data analysis was performed using STATA 10 (StataCorp, College Station, TX).

Standard protocol approvals, registrations, and patient consents. The ethics committee for research on humans of the Canton of Vaud (ECCV) approved our study.

(A) Age distribution of missed (red) and diagnosed (blue) acute ischemic strokes. (B) NIHSS distribution of missed (red) and diagnosed (blue) acute ischemic strokes. NIHSS 5 NIH Stroke Scale.

RESULTS In the observation period of 8.25 years, 2,200 patients were included in ASTRAL, of whom 47 (2.1%) were AIS-C at initial ED evaluation. Patients’ characteristics are described in table 1 and table e-1 on the Neurology® Web site at Neurology.org. The AIS-C patients were younger, and the age distribution was bimodal (figure 1): a first age peak occurred at a mean of 32.3 years (SD 4.17), accounting for 38% of the population, and a second peak at a mean of 67.4 years (SD 12.97) accounting for the remaining 62%. The 2 peaks of these age groups were differently distributed within the AIS-C population (odds ratio 4.48, 95% confidence interval 1.84–10.92). On admission, the NIHSS score was lower in the AIS-C group with a median NIHSS score of 3 (vs 6 in the AIS group), but this did not reach statistical significance. The AIS-C group had a bimodal NIHSS distribution as shown in figure 1: there was a first peak at a mean of 4 points (SD 3.39) accounting for 87% of the population and a second at a mean of 29 points (SD 4.01) accounting for the remaining 13%. Comparison of these 2 NIHSS score distributions within the stroke chameleons did not reach statistical significance (p 5 0.15). In univariate analysis, risk factors and prestroke medication, hypertension, and the use of antihypertensive and lipid-lowering drugs were more frequent and smoking was less prevalent in the AIS group. Regarding symptoms, eye deviation, paresis, and sensory deficit were less frequent in the AIS-C group. The patients with AIS-C had a higher proportion of Neurology 85

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Table 2

Independent associations comparing missed strokes with correctly diagnosed patients in the multivariate analysis (n 5 2,137) OR (95% CI)

p Value

Age (for 1-y increase above 18 y)

0.98 (0.96–0.99)

,0.01

Pretreatment with hypolipidemic drugs

0.29 (0.09–0.97)

0.04

NIHSS score on admission (for 1-point increase)

0.99 (0.96–1.04)

0.99

Eye deviation

0.21 (0.05–0.94)

0.04

Diastolic blood pressure

0.98 (0.96–0.99)

0.04

Cerebellar stroke

3.78 (1.87–7.63)

,0.01

Abbreviations: CI 5 confidence interval; NIHSS 5 NIH Stroke Scale; OR 5 odds ratio.

bilateral, multiterritory, cerebellar, and thalamic locations of stroke, whereas patients with AIS had an increased prevalence of frontal lobe strokes. Stroke mechanism analysis showed that the missed stroke patients were more likely to have a cardiac cause or dissection rather than atherosclerotic or lacunar etiology (tables 1 and e-1). The multivariate logistic model yielded 5 significant variables when adjusted for the covariates from the bivariate analysis (table 2). Patients with AIS-C were younger, had less pretreatment with hypolipidemic drugs, less frequent eye deviation, lower diastolic admission blood pressure, and more frequent cerebellar stroke localization. On a descriptive level, several circumstantial patterns led to an AIS-C (table 3). The most frequent situation was incorrect attribution of stroke symptoms to other neurologic diseases, in particular to acute confusional state, epileptic seizures, and central nervous or systemic infections (for details, see table e-2). Then “decreased level of consciousness/coma” was the second most frequent pattern leading to misdiagnosis. Third, a concomitant neurologic or psychiatric

Table 3

Patterns in the diagnostic process leading to missing acute ischemic strokes

Pattern

No. (%)

Stroke symptoms attributed to another diseasea

38 (80.8)

Attributed to another neurologic diseasea Attributed to nonneurologic diseasea

a b

4

8 (17.0) 10 (21.3)

Stroke symptoms attributed to a concomitantly present conditionb

9 (19.1)

Attributed to concomitant neurologic conditionb

5 (10.6)

Attributed to concomitant psychiatric conditionb

4 (8.5)

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In a large consecutive AIS series in the ED of a stroke unit–equipped university hospital with 24-hour availability of neurology residents and registrars, we found 2.1% AIS-C (chameleons). Younger age, less prestroke hypolipidemic drug use, less frequent eye deviation, lower diastolic blood pressure, and more frequent cerebellar stroke localization were independent risk factors of AIS-C. Adjusted outcome analysis was poorer at 12 months and mortality increased in the misdiagnosed group. Although the 2.1% rate of misdiagnosis in our center seems low, it is likely an underestimation given that DISCUSSION

20 (42.6)

Unexplained decreased level of consciousness

Details: see table e-2. Details: see table e-3.

condition was considered the cause of the current symptoms (for details, see table e-3A). Radiologic misinterpretation of images contributed to the wrong diagnosis in 19 of 47 patients (40.4%) leading to consideration of other differential diagnoses: in 5 AIS-C, the early ischemic changes on noncontrast CT were not identified; in 4 patients, an acute or subacute lesion was interpreted as another disease (i.e., as multiple sclerosis [1], as glioma [1], attributed to concomitant toxoplasmosis [1], and attributed to a previous stroke in the same territory [1]). In 10 AIS-C cases, no early ischemic changes or vascular or perfusion imaging alterations were seen and were wrongly interpreted as absence of stroke. The ED physicians did not consider the AIS diagnosis in 43 patients with chameleons (91.5%). In 29 of these patients, neurologic consultation (by a boardeligible senior registrar or neurology resident in training) was obtained, and the consultant did not make the correct diagnosis in 15 of these. Furthermore, the neurologic consultant considered the ED physicians’ suspicion of stroke as incorrect in 4 other patients. They therefore contributed to the nondiagnosis of stroke in 19 of 33 patients (57.6%) (figure e-1). The modalities by which the correct diagnosis was made are described in table e-3B. Applying thrombolysis criteria of hospital arrival within 4 hours, admission NIHSS score $4 and no particular hemorrhage risk, 11 of the 47 patients with AIS-C (23.4%) should have been given thrombolysis. In the correctly diagnosed control population, the actual number of patients who received thrombolysis was 19.9%. Regarding 12-month outcome, 1 of 47 (2.1%) in the AIS-C group and 85 of 2,153 (3.9%) in the AIS group lacked data. As for recurrences, 1 of 47 (2.1%) in the AIS-C group and 182 of 2,153 (8.5%) in the AIS group lacked data. In adjusted analysis, patients with AIS-C showed worse neurologic outcomes and a higher mortality at 12 months than patients with AIS. The increased rate of recurrent ischemic cerebrovascular events in AIS-C did not reach statistical significance before and after adjustment (table 4).

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Table 4

Results for favorable outcome, mortality, and cerebrovascular event recurrences within the first 12 months

Overall population

AIS-C

AIS

Unadjusted OR (95% CI)

p Value

Adjusted OR (95% CI)

p Value

No. of patients

2,200

47

2,153









Favorable outcome

1,296 (61.3)

23 (50.0)

1,273 (61.6)

0.62 (0.35–1.12)

0.12

0.21 (0.09–0.46)

,0.01

Mortality

416 (19.7)

14 (30.4)

402 (19.4)

1.81 (0.95–3.43)

0.07

4.37 (1.81–10.54)

,0.01

Recurrent ischemic cerebrovascular event

201 (10.0)

6 (13.3)

195 (9.9)

1.40 (0.59–3.35)

0.45

1.68 (0.68–4.12)

0.26

Abbreviation: AIS 5 acute ischemic stroke; AIS-C 5 acute ischemic stroke chameleon; CI 5 confidence interval; OR 5 odds ratio. Results are given as numbers, as % of available data, and as OR.

some missed strokes may never be identified correctly. A previous study17 found a similar rate of 2.8%, while others found a higher frequency of 14.0% to 15.3%6,18 in young AIS patients. In a series of 475 consecutive patients presenting with a chief complaint of vertigo, 6% of strokes were missed.19 Another recent study20 recorded a misdiagnosis rate ranging from 1.2% to 12.7% in a large series of 198,819 stroke patients admitted to various ED types. Younger age, as already reported,6,20 a lower frequency of prestroke use of lipid-lowering drugs, and lower blood pressure at admission indicate that a more benign cerebrovascular risk profile leads to AIS-C. Even though this observation is understandable, it shows the importance of educating medical personnel of the possibility of stroke in young patients with acute, unexplained neurologic symptoms. In contrast to other studies, we did not find any differences between the 2 populations in ethnicity, sex, or insurance status.20 Median stroke severity measured by the NIHSS was clearly lower in AIS-C. This did not reach statistical significance, however, likely because of the wide distribution of the NIHSS scores in the AIS-C with a second NIHSS peak of severe strokes at an NIHSS score of 29 (figure 1). Besides mild stroke, very severe strokes were also missed. This is best explained by patients arriving in stupor or coma (11 of the 47 chameleons) mostly due to basilar artery occlusion. This presentation may mislead physicians to suspect a metabolic, toxic, or anoxic encephalopathy rather than stroke.21,22 It also suggests that physicians emphasize lateralizing signs to identify stroke. This is further underlined by the absence of eye deviation as an important risk factor for AIS-C. It has been reported that the presence of atypical stroke symptoms produced a 43% risk of stroke not being considered in the differential diagnosis.18 Finally, our multivariate analysis also identified cerebellar stroke localization as a risk factor. Cerebellar infarction or stroke presenting with vestibular symptoms is one of the most frequently missed stroke types.4,6,9,10,17,18,21,23

When examining patterns leading to wrong diagnosis, the attribution of acute neurologic symptoms to other neurologic diseases, or even to nonneurologic diseases, was most prevalent (table 3). We found similar erroneous diagnoses (table e-2) to the ones described in the literature; syncope and hypertensive emergency were 2 additional false diagnoses.2 Furthermore, concomitant and preexisting neurologic and psychiatric conditions often masked correct stroke diagnosis (table e-3A). Occasionally imaging studies, in particular CTbased imaging, were misinterpreted, either because subtle early ischemic changes were overlooked or because a normal CT was considered sufficient evidence to rule out a stroke. MRI has higher sensitivity than CT24,25 for AIS located in the posterior fossa, a common location for AIS-C. MRI may also positively identify stroke imitators more frequently than CT, and magnetic resonance–based imaging should therefore be the preferred modality to clarify unexplained acute central neurologic symptoms and signs. ED physicians were a little less than twice as likely as neurologists or neurologists in training to miss the right diagnosis (figure e-1). One obvious explanation is that ED physicians see all patients presenting to the ED so their probability of missing a stroke is higher than neurologists who only see selected cases. However, our study highlights AIS patterns that may be addressed by education targeting ED physicians. The presence of an in-house neurology training program is also associated with less AIS-C in another study,9 but may not be a practical solution for EDs. This indicates that higher level of expertise may indeed decrease the rate of missed strokes. Still, even specialists seem at some risk of missing the correct neurologic diagnosis. Missing a stroke had direct consequences on management and potentially outcome: if correctly diagnosed, 23.4% of patients with stroke chameleons could have received a thrombolysis, the most effective established treatment for AIS.26 Despite younger age and lower initial NIHSS score, patients with AIS-C had worse functional status and lower survival at 12 months. This may be explained by the absence of Neurology 85

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thrombolysis, delayed stabilization of vital signs in the ED, or lack of secondary prevention. We have previously shown that delayed hospital arrival is a risk factor for poorer outcome after ischemic stroke.27 Missing the correct diagnosis may also lead to later admission to stroke units where organized stroke care, systematic assessment of dysphagia, early mobilization, acute rehabilitation, and earlier implementation of appropriate secondary prevention may be responsible for improved outcomes.28,29 We indeed found a higher 12-month stroke and TIA recurrence risk but our study did not have a large enough sample to reach statistical significance. Based on our data, some stroke chameleons may be preventable in part by educating physicians about unusual presentations of stroke. Also, health professionals in contact with acute neurologic problems should keep in mind that stroke may occur simultaneously with other neurologic, psychiatric, or medical conditions. Finally, lowering the threshold for neurologic consultation and the more systematic use of multimodal CT and MRI techniques in the ED may be suggested. The strengths of our study are the large population with a prespecified data collection and the use of a multivariate analysis to search for adjusted associations. Limitations are its retrospective design, the unknown number of AIS-C who were never diagnosed, the limited number of available AIS-C for analysis in our study, and the absence of a known delay from stroke onset to the time of the correct diagnosis (insufficiently documented in the medical charts). We found that younger age, a low cerebrovascular profile, and unusual clinical presentations, such as absence of focal neurologic deficits, cerebellar symptoms, and coma, predispose to missing strokes. Also, coexisting medical conditions and the performance of physicians influence the correct diagnosis. Given that missing the correct stroke diagnosis is associated with a worse clinical outcome, prevention through education may be needed for ED medical personnel. AUTHOR CONTRIBUTIONS Dr. Benjamin Richoz was involved in study design, data collection, analysis, and drafting of the manuscript. Drs. Olivier Hugli, Fabrice Dami, and Pierre-Nicolas Carron were involved in revising the manuscript and providing critical content. Dr. Mohamed Faouzi participated in study design and was responsible for statistical analysis. Dr. Patrik Michel was involved in study design, data collection, analysis, drafting of the manuscript, and supervision. All authors contributed to final manuscript revision and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

STUDY FUNDING No targeted funding reported.

DISCLOSURE B. Richoz, O. Hugli, F. Dami, P. Carron, and M. Faouzi report no disclosures relevant to the manuscript. P. Michel received research grants 6

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from the Swiss National Science Foundation and the Swiss Heart Foundation, receives speaker fees from Bayer, Boehringer Ingelheim, Covidien, and St. Jude Medical, honoraria from scientific advisory boards from Boehringer Ingelheim, Bayer, Pfizer, Amgen, receives consulting fees from Pierre-Fabre, and receives travel support from Boehringer Ingelheim and Bayer. He uses all speaker fees and honoraria for stroke research and education and serves on the editorial board of Stroke and the International Journal of Stroke. He serves on the steering committee of BASICS, the International PFO-Consortium, the DSMB of CLOSE, and the ICHadjudication committee from CLOTBUST-ER. Go to Neurology.org for full disclosures.

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Acute stroke chameleons in a university hospital: Risk factors, circumstances, and outcomes Benjamin Richoz, Olivier Hugli, Fabrice Dami, et al. Neurology published online July 15, 2015 DOI 10.1212/WNL.0000000000001830 This information is current as of July 15, 2015 Updated Information & Services

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Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 2015 American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.

Acute stroke chameleons in a university hospital: Risk factors, circumstances, and outcomes.

To identify risk factors, circumstances, and outcomes for individuals with acute ischemic stroke (AIS) chameleons (AIS-C) arriving in the emergency de...
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