Cerebellar infarction: comparison of computed tomography and magnetic resonance imaging

Head impulse, nystagmus, and test of skew examination for diagnosing central causes of acute vestibular syndrome

BACKGROUND

Dizziness is a common reason for people to seek medical care. Acute vestibular syndrome (AVS) is a specific type of dizziness, which can include severe vertigo, nausea and vomiting, nystagmus, or unsteadiness. Acute vestibular syndrome can be due to peripheral or central causes. It is important to determine the cause, as the intervention and outcomes differ if it is from a peripheral or central cause. Clinicians can assess for the cause using risk factors, patient history, examination findings, or advanced imaging, such as a magnetic resonance imaging (MRI). The head impulse, nystagmus, test of skew (HINTS) examination is a three-part examination performed by clinicians to determine if AVS is due to a peripheral or central cause. This includes assessing how the eyes move in response to rapidly turning a person's head (head impulse), assessing the direction of involuntary eye movements (nystagmus), and assessing whether the eyes are aligned or misaligned (test of skew). The HINTS Plus examination includes an additional assessment of auditory function.

OBJECTIVES

To assess the diagnostic accuracy of the HINTS and HINTS Plus examinations, with or without video assistance, for identifying a central etiology for AVS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Google Scholar, the International HTA database, and two trials registers to September 2022.

SELECTION CRITERIA

We included all retrospective and prospective diagnostic test accuracy studies that evaluated the HINTS or HINTS Plus test used in a primary care clinic, an urgent care clinic, the emergency department, or during inpatient hospitalization against a final diagnosis of a central etiology of AVS, as defined by the reference standard of advanced imaging or final diagnosis by a neurologist.

DATA COLLECTION AND ANALYSIS

Two review authors independently determined eligibility of each study according to eligibility criteria, extracted data, assessed the risk of bias, and determined the certainty of evidence. Disagreements were adjudicated by consensus or a third review author if needed. The primary outcome was the diagnostic accuracy of the HINTS and HINTS Plus examinations for identifying a central etiology for AVS, conducted clinically (clinician visual assessment) or with video assistance (e.g. video recording with goggles); we independently assessed the clinical and video-assisted examinations. Subgroup analyses were performed by provider type (e.g. physicians, non-physicians), time from symptom onset to presentation (e.g. less than 24 hours, longer than 24 hours), reference standard (e.g. advanced imaging, discharge diagnosis), underlying etiology (e.g. ischemic stroke, alternative etiologies [hemorrhagic stroke, intracranial mass]), study setting (e.g. outpatient [outpatient clinic, urgent care clinic, emergency department], inpatient), physician level of training (e.g. resident, fellow/attending), physician specialty (e.g. otolaryngology, emergency medicine, neurology, and neurologic subspecialist [e.g. neuro-ophthalmology, neuro-otology]), and individual diagnostic accuracy of each component of the examination (e.g. head impulse, direction-changing nystagmus, test of skew). We created 2 x 2 tables of the true positives, true negatives, false positives, and false negatives and used these data to calculate the sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with 95% confidence intervals (95% CI) for each outcome.

MAIN RESULTS

We included 16 studies with a total of 2024 participants (981 women and 1043 men) with a mean age of 60 years. Twelve studies assessed the HINTS examination; five assessed the HINTS Plus examination. Thirteen studies were performed in the emergency department; half were performed by neurologists. The clinical HINTS examination (12 studies, 1890 participants) was 94.0% (95% confidence interval [CI] 82.0% to 98.2%) sensitive, and 86.9% (95% CI 75.3% to 93.6%) specific (low-certainty evidence). The video-assisted HINTS examination (3 studies, 199 participants) was 85.0% to 100% sensitive (low-certainty evidence), and 38.9% to 100% specific (very low-certainty evidence). The clinical HINTS Plus examination (5 studies, 451 participants) was 95.3% (95% CI 78.4% to 99.1%) sensitive, and 72.9% (95% CI 44.4% to 90.1%) specific (low-certainty evidence). The video-assisted HINTS Plus examination (2 studies, 163 participants) was 85.0% to 93.8% sensitive, and 28.6% to 38.9% specific (moderate-certainty evidence). Subgroup analyses were limited, as most studies were conducted in the emergency department, by physicians, and with MRI as a reference standard. Time from symptom onset to presentation varied across studies. Three studies were at high risk of bias and three studies were at unclear risk of bias for participant selection. Three studies were at unclear risk of bias for the index test. Four studies were at unclear risk of bias for the reference standard. Two studies were at unclear risk of bias for flow and timing. One study had unclear applicability concerns for participant selection. Two studies had high applicability concerns for the index test and two studies had unclear applicability concerns for the index test. No studies had applicability concerns for the reference standard.

AUTHORS' CONCLUSIONS

The HINTS and HINTS Plus examinations had good sensitivity and reasonable specificity for diagnosing a central cause for AVS in the emergency department when performed by trained clinicians. Overall, the evidence was of low certainty. There were limited data for the role of video-assistance or specific subgroups. Future research should include more high-quality studies of the HINTS and HINTS Plus examination; assessment of inter-rater reliability across users; accuracy across different providers, specialties, and experience; and direct comparison with no HINTS or MRI to assess the effect on clinical care.

The "Vestibular Eye Sign"-"VES": a new radiological sign of vestibular neuronitis can help to determine the affected vestibule and support the diagnosis

INTRODUCTION

Nystagmus is a valuable clinical finding. Although nystagmus is often described by the direction of its quick phases, it is the slow phase that reflects the underlying disorder. The aim of our study was to describe a new radiological diagnostic sign called "Vestibular Eye Sign"-VES. This sign is defined as an eye deviation that correlates with the slow phase of nystagmus (vestibule pathological side), which is seen in acute vestibular neuronitis and can be assessed on a CT head scan.

MATERIALS AND METHODS

A total of 1250 patients were diagnosed with vertigo in the Emergency Department at Ziv Medical Center (ED) in Safed, Israel. The data of 315 patients who arrived at the ED between January 2010 and January 2022 were collected, with criteria eligible for the study. Patients were divided into 4 groups: Group A, "pure VN", Group B, "non-VN aetiology", Group C, BPPV patients, and Group D, patients who had a diagnosis of vertigo with unknown aetiology. All groups underwent head CT examination while in the ED.

RESULTS

In Group 1, pure vestibular neuritis was diagnosed in 70 (22.2%) patients. Regarding accuracy, VES (Vestibular Eye Sign) was found in 65 patients in group 1 and 8 patients in group 2 and had a sensitivity of 89%, specificity of 75% and a negative predictive value of 99.4% in group 1-pure vestibular neuronitis.

CONCLUSION

VN is still a clinical diagnosis, but if the patient undergoes head CT, we suggest using the "Vestibular Eye Sign" as a complementary sign. As per our findings, this is a valuable sign on CT imaging for diagnosing the pathological side of isolated pure VN. It is sensitive to support a diagnosis with a high negative predictive value.

Misdiagnosis of Cerebellar Infarcts and Its Outcome

Cerebellar infarction, a rare category of stroke, is often misdiagnosed but not given much importance in the available literature. Its presentation overlaps with symptoms of other neurologic, cardiovascular, gastrointestinal, and systemic conditions and therefore is nonspecific. Early diagnosis and management of cerebellar strokes are of utmost importance as the lack of a proper diagnosis may increase overall morbidity and mortality. Lack of awareness of the warning signs and symptoms, non-specificity of symptoms, absence of neurological deficits, and imaging discrepancies are some of the factors contributing to misdiagnosis and delayed treatment. If symptomatology is considered, it is found that symptoms of posterior circulation stroke were more frequently misdiagnosed compared to anterior circulation. Nausea and vomiting increased the chance further. Some other rare presentations include gastrointestinal symptoms, isolated vertigo, and symptoms of inner ear disease. Overdependence on radiological investigations often masks the significance of clinical examination. Ischemic stroke may appear normal in the initial 48 hours in the computed tomography scan of the brain or bony artefacts may hide the lesion. Permanent disabling deficits can follow a cerebellar stroke and the complications, which include hydrocephalus, brain stem compression, and gait abnormalities, necessitate prompt identification and management. In this review article, we aim at analysing various case reports of cerebellar infarction, the most common presentations that were under-evaluated, and their outcomes, thereby highlighting the importance of proper diagnosis and reporting of cerebellar infarction in the future. A thorough knowledge of the association between various clinical presentations of cerebellar stroke and its misdiagnosis helps clinicians to be more vigilant about the disease.

Head impulse, nystagmus, and test of skew examination for diagnosing central causes of acute vestibular syndrome

This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows:

The primary aim of this review will be to assess the diagnostic accuracy of the HINTS examination for identifying a central etiology for AVS.

BET 1: Ruling out cerebellar infarct in the emergency department with CT scan

A short-cut review of the available medical literature was carried out to establish whether CT scanning can rule out cerebellar infarction. After abstract review, two papers were found to answer this clinical question using the detailed search strategy. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. It is concluded that there is insufficient evidence to draw a conclusion.

Acute Dizziness, Vertigo, and Unsteadiness

Vestibular symptoms, including dizziness, vertigo, and unsteadiness, are common presentations in the emergency department. Most cases have benign causes, such as vestibular apparatus dysfunction or orthostatic hypotension. However, dizziness can signal a more sinister condition, such as an acute cerebrovascular event or high-risk cardiac arrhythmia. A contemporary approach to clinical evaluation that emphasizes symptom duration and triggers along with a focused oculomotor and neurologic examination can differentiate peripheral causes from more serious central causes of vertigo. Patients with high-risk features should get brain MRI as the diagnostic investigation of choice.

From Cerebellar Apoplexy in 1849 to Cerebellar Stroke in the 2020s: Robert Dunn's Contribution

Stroke of the cerebellum represents about 10% of strokes of the brain. Both infarction and hemorrhage manifest with symptoms related to the location and extent of the lesion(s). Bilateral cerebellar infarcts constitute up to one third of all cerebellar infarctions. The leading cause of cerebellar infarcts is emboli of cardiac origin or from intra-arterial sources. Potential complications include brainstem compression and hydrocephalus. Malignant cerebellar edema is a life-threatening complication of ischemic posterior circulation stroke requiring urgent management. The advent of MRI has revolutionized the early diagnosis in vivo, showing small and large territorial infarcts, hemorrhages, and venous infarcts. Endovascular procedures are growingly applied and are impacting on the prognosis of stroke, although cerebellar stroke from occlusion of small cerebellar arteries is currently not accessible to thrombectomy. Surgical procedures of space-occupying stroke include external ventricular drainage, suboccipital craniotomy, or combined procedures. In 1849, Robert Dunn (1799-1877), an English surgeon, reported the details of a case of apoplexy of the cerebellum in a 52-year-old man, pointing to the importance of post-mortem studies of patients followed meticulously during lifetime. Dunn discussed inflammation surrounding hemorrhage as a source of cerebral degeneration, linking for the first time cerebellar stroke, neuroinflammation, and atherosclerosis.

Serum miRNA125a-5p, miR-125b-5p, and miR-433-5p as biomarkers to differentiate between posterior circulation stroke and peripheral vertigo

Background

Acute vertigo is a common presentation of inner ear disease. However, it can also be caused by more serious conditions, especially posterior circulation stroke. Differentiating between these two conditions by clinical presentations and imaging studies during the acute phase can be challenging. This study aimed to identify serum microRNA (miRNA) candidates that could differentiate between posterior circulation stroke and peripheral vertigo, among patients presenting with acute vertigo.

Methods

Serum levels of six miRNAs including miR-125a-5p, miR-125b-5p, miR-143-3p, miR-342-3p, miR-376a-3p, and miR-433-5p were evaluated. Using quantitative reverse-transcription polymerase chain reaction (RT-qPCR), the serum miRNAs were assessed in the acute phase and at a 90 day follow-up visit.

Results

A total of 58 patients with posterior circulation stroke (n = 23) and peripheral vertigo (n = 35) were included in the study. Serum miR-125a-5p (P = 0.001), miR-125b-5p (P <  0.001), miR-143-3p (P = 0.014) and miR-433-5p (P = 0.0056) were present at significantly higher levels in the acute phase, in the patients with posterior circulation infarction. Based on the area under the receiver operating characteristic curve (AUROC) only miR-125a-5p (0.75), miR-125b-5p(0.77), and miR-433-5p (0.71) had an acceptable discriminative ability to differentiate between the central and peripheral vertigo. A combination of miRNAs revealed no significant improvement of AUROC when compared to single miRNAs.

Conclusion

This study demonstrated the potential of serum miR-125a-5p, miR-125b-5p, and miR-433-5p as biomarkers to assist in the diagnosis of posterior circulation infarction among patients presenting with acute vertigo.

[Acute vestibular syndrome in emergency departments : Clinical differentiation of peripheral and central vestibulopathy]

INTRODUCTION

The differentiation between central and peripheral vestibular disorders is difficult in some cases, especially during the clinical routine of an emergency department (ED) without otoneurological diagnostic equipment. This study evaluated the frequency of vestibular pseudoneuritis as distinguished from acute peripheral vestibular disorders in patients who were admitted to hospital with the suspicion of vestibular neuropathy (VN).

METHODS

This retrospective study analyzed the results of anamnestic and clinical examinations of 315 patients admitted to the emergency department and the inpatient otoneurological examination results as well as the imaging of morphological alterations. In the ED, the clinical examination by a neurologist and an otorhinolaryngologist resulted in the characteristic signs of peripheral VN but no further evidence of a neurological disorder. Patients without signs of a peripheral vestibular disorder in the otoneurological diagnostics subsequently underwent cerebral magnetic resonance imaging scans (cMRI).

RESULTS

Suspected isolated VN could be confirmed in 69% of the patients; however, in a further 29% of the patients neither the suspected isolated VN nor an ischemic pathology of the central nervous system as a cause of the vertigo could be confirmed. Additional cMRI scans revealed that 2% of patients suffered from an infarction of the mesencephalon, the pons, the medulla oblongata and the cerebellum.

CONCLUSION

In rare cases central cerebral disorders mimic the pattern of a peripheral vestibular disorder. Despite thorough history taking, neurological and otolaryngological clinical examinations, it is not always possible to distinguish central and peripheral vestibular disorders of patients in emergency care suffering from acute vertigo. Video oculography-assisted caloric testing and the video head impulse test are recommended to confirm a peripheral VN. In cases without confirmation of suspected NV in otoneurological diagnostics, infarction of the mesencephalon, brain stem and cerebellum should be excluded by diffusion-weighted cMRI.

Telling friend from foe in emergency vertigo and dizziness: does season and daytime of presentation help in the differential diagnosis?

Distinguishing between serious (e.g., stroke) and benign (e.g., benign paroxysmal positional vertigo, BPPV) disorders remains challenging in emergency consultations for vertigo and dizziness (VD). A number of clues from patient history and clinical examination, including several diagnostic index tests have been reported recently. The objective of the present study was to analyze frequency and distribution patterns of specific vestibular and non-vestibular diagnoses in an interdisciplinary university emergency room (ER), including data on daytime and season of presentation. A retrospective chart analysis of all patients seen in a one-year period was performed. In the ER 4.23% of all patients presented with VD (818 out of 19,345). The most frequent-specific diagnoses were BPPV (19.9%), stroke/transient ischemic attack (12.5%), acute unilateral vestibulopathy/vestibular neuritis (UVH; 8.3%), and functional VD (8.3%). Irrespective of the diagnosis, the majority of patients presented to the ER between 8 a.m. and 4 p.m. There are, however, seasonal differences. BPPV was most prevalent in December/January and rare in September. UVH was most often seen in October/November; absolute and relative numbers were lowest in August. Finally, functional/psychogenic VD was common in summer and autumn with highest numbers in September/October and lowest numbers in March. In summary, daytime of presentation did not distinguish between diagnoses as most patients presented during normal working hours. Seasonal presentation revealed interesting fluctuations. The UVH peak in autumn supports the viral origin of the condition (vestibular neuritis). The BPPV peak in winter might be related to reduced physical activity and low vitamin D. However, it is likely that multiple factors contribute to the fluctuations that have to be disentangled in further studies.

A comparison of benign positional vertigo and stroke patients presenting to the emergency department with vertigo or dizziness

PURPOSE

To compare imaging utilization between patients presenting to the emergency department (ED) with vertigo and dizziness (VDS) who are diagnosed with stroke and benign paroxysmal positional vertigo (BPPV).

METHODS

All patients presenting to the ED with VDS (January 2014-June 2018) were identified. Those with a discharge diagnosis of stroke and BPPV were analyzed.

RESULTS

17,884 patients presented to with VDS. 452 were diagnosed with BPPV and 174 with acute stroke. 55.7% of stroke patients had at least one neurologic symptom beyond VDS, 63.8% had a positive neurologic exam, and 80.5% had either; 90.2% had at least one stroke risk factor (RF). 42.0% of BPPV patients received imaging, of which 24.7% had neurologic symptoms beyond VDS, 16.3% had neurologic exam findings, and 34.2% had either (P < 0.001, as compared to stroke). 43 patients (22.6%) lacked neurologic symptoms, exam findings, and stroke RFs; 40 had an adequate HINTS (head impulse, nystagmus, skew) exam. The most common imaging modality received by BPPV patients was plain CT Head (54.2%), followed by CT/CTA (43.7%), and MRI brain (26.3%). CT head was the initial imaging of choice in 44.7% and CT/CTA in 42.6%.

CONCLUSIONS

Imaging utilization in BPPV patients presenting with VDS is high. The profile of patients with BPPV that received imaging was substantially more benign than that of stroke patients (a quarter had no neurologic symptoms, exam findings, or stroke RFs). The HINTS exam was underutilized, and computed tomography was heavily utilized despite well-established limitations in diagnosing posterior circulation strokes. This study highlights the need for increased training in the HINTS exam, narrowing of the scope for computed tomography, and a higher threshold for imaging patients with isolated VDS.

Value of Head CT Scan in the Emergency Department in Patients with Vertigo without Focal Neurological Abnormalities

BACKGROUND:

Vertigo is a common symptom and reason for admission to the emergency department (ED).

AIM:

This research aimed to determine the incidence of clinically significant findings on computed tomography (CT) in patients with vertigo without focal neurological abnormalities in the ED.

MATERIAL AND METHODS:

The results of the native CT scans in the ED were retrospectively analysed. Exclusion criteria included: focal neurological abnormalities, underlying malignancy, brain metastasis, previous brain operation, headache, fever, nausea, vomiting, head trauma, coagulopathy. As a clinically significant finding, we took into an account tumour, haemorrhage and acute ischemic lesion. 72 patients fulfilled the set criteria, present vertigo, without focal neurological abnormalities. Out of 72 patients with a median age of 62 (23-87) years old, 54% of the patients were female, and 46% were male.

RESULTS:

Normal CT findings were found in 44 patients (61.1%), 28 patients (38.9%) had pathological findings, out of that number 23 (31.9%) findings were clinically irrelevant and 5 (6.9%) were clinically significant. Out of the 5 clinically significant findings, tumour process was found in 3 (4.2%) patients, haemorrhage was found in 1 (1.4%) patient, and the ischemic lesion was found in 1 (1.4%) patient. Additional evaluation of five clinically significant findings showed a change of initial diagnosis in one case, but the significance of the finding remained the same.

CONCLUSION:

Our study demonstrates a low diagnostic yield of head CT examination with 6.9% of clinically significant findings in patients with vertigo without focal neurological abnormalities.

Recent Advances in Cerebellar Ischemic Stroke Syndromes Causing Vertigo and Hearing Loss

Cerebellar ischemic stroke is one of the common causes of vascular vertigo. It usually accompanies other neurological symptoms or signs, but a small infarct in the cerebellum can present with vertigo without other localizing symptoms. Approximately 11 % of the patients with isolated cerebellar infarction simulated acute peripheral vestibulopathy, and most patients had an infarct in the territory of the medial branch of the posterior inferior cerebellar artery (PICA). A head impulse test can differentiate acute isolated vertigo associated with PICA territory cerebellar infarction from more benign disorders involving the inner ear. Acute hearing loss (AHL) of a vascular cause is mostly associated with cerebellar infarction in the territory of the anterior inferior cerebellar artery (AICA), but PICA territory cerebellar infarction rarely causes AHL. To date, at least eight subgroups of AICA territory infarction have been identified according to the pattern of neurotological presentations, among which the most common pattern of audiovestibular dysfunction is the combined loss of auditory and vestibular functions. Sometimes acute isolated audiovestibular loss can be the initial symptom of impending posterior circulation ischemic stroke (particularly within the territory of the AICA). Audiovestibular loss from cerebellar infarction has a good long-term outcome than previously thought. Approximately half of patients with superior cerebellar artery territory (SCA) cerebellar infarction experienced true vertigo, suggesting that the vertigo and nystagmus in the SCA territory cerebellar infarctions are more common than previously thought. In this article, recent findings on clinical features of vertigo and hearing loss from cerebellar ischemic stroke syndrome are summarized.

Dizziness in a community hospital: central neurological causes, clinical predictors, and diagnostic yield and cost of neuroimaging studies

Objectives: Neuroimaging is contributing to the rising costs of dizziness evaluation. This study examined the rate of central neurological causes of dizziness, relevant clinical predictors, and the costs and diagnostic yields of neuroimaging in dizziness assessment. Methods: We retrospectively reviewed the records of 521 adult patients who visited the hospital during a 12-month period with dizziness as the chief complaint. Clinical findings were analyzed using Fisher's exact test to determine how they correlated with central neurological causes of dizziness identified by neuroimaging. Costs and diagnostic yields of neuroimaging were calculated. Results: Of the 521 patients, 1.5% had dizziness produced by central neurological causes. Gait abnormalities, limb ataxia, diabetes mellitus, and the existence of multiple neurological findings predicted central causes. Cases were associated with gait abnormalities, limb ataxia, diabetes mellitus, and the existence of multiple neurological findings . Brain computed tomography (CT) and magnetic resonance imaging (MRI) were performed in 42% and 9.5% of the examined cases, respectively, with diagnostic yields of 3.6% and 12%, respectively. Nine cases of dizziness were diagnosed from 269 brain scans, costing $607 914. Conclusion: Clinical evaluation can predict the presence of central neurological causes of dizziness, whereas neuroimaging is a costly and low-yield approach. Guidelines are needed for physicians, regarding the appropriateness of ordering neuroimaging studies. Abbreviations: OR: odds ratio; CI: confidence interval; ED: emergency department; CT: computed tomography; MRI: magnetic resonance imaging; HINTS: Head impulse, Nystagmus, Test of skew.

A New Approach to the Diagnosis of Acute Dizziness in Adult Patients

Dizziness is a common chief complaint in emergency medicine. The differential diagnosis is broad and includes serious conditions, such as stroke, cardiac arrhythmia, hypovolemic states, and acute toxic and metabolic disturbances. Emergency physicians must distinguish the majority of patients who suffer from benign self-limiting conditions from those with serious illnesses that require acute treatment. Misdiagnoses are frequent and diagnostic test costs high. The traditional approach does not distinguish benign from dangerous causes and is not consistent with best current evidence. This article presents a new approach to the diagnosis of acutely dizzy patients that highly leverages the history and the physical examination.

Misdiagnosis of cerebellar infarctions

BACKGROUND

This retrospective study addresses for the first time the differences in clinical features and outcomes between those individuals with a cerebellar infarct who were correctly diagnosed on initial presentation compared to those who experienced delayed diagnosis.

METHODS

A retrospective review was conducted of our stroke registry from 09/2003 to 02/2011. Forty seven patients had an isolated cerebellar infarction confirmed by MRI. Misdiagnosis was defined as the diagnosis given by the first physician.

RESULTS

Among 47 patients identified, 59.6% had delayed diagnosis. Five patients in the correct diagnosis group received intravenous tissue plasminogen activator, compared to none in the delayed diagnosis group. Complaints of weakness were protective from delayed diagnosis (OR 0.087, 95% CI 0.019-0.393, p=0.001). Conclusion : Patients with an isolated cerebellar infarction need to be considered when patients present with acute non-specific symptoms. Critical components of the neurological examination are omitted which are imperative to diagnose cerebellar infarcts. A thorough neurological examination may increase clinical suspicion of an ischemic stroke.

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

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 = 0.04), and lower diastolic admission blood pressure (OR 0.98 p = 0.04). They showed less eye deviation (OR 0.21, p = 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.

Can emergency physicians accurately and reliably assess acute vertigo in the emergency department?

OBJECTIVE

To validate a clinical diagnostic tool, used by emergency physicians (EPs), to diagnose the central cause of patients presenting with vertigo, and to determine interrater reliability of this tool.

METHODS

A convenience sample of adult patients presenting to a single academic ED with isolated vertigo (i.e. vertigo without other neurological deficits) was prospectively evaluated with STANDING (SponTAneousNystagmus, Direction, head Impulse test, standiNG) by five trained EPs. The first step focused on the presence of spontaneous nystagmus, the second on the direction of nystagmus, the third on head impulse test and the fourth on gait. The local standard practice, senior audiologist evaluation corroborated by neuroimaging when deemed appropriate, was considered the reference standard. Sensitivity and specificity of STANDING were calculated. On the first 30 patients, inter-observer agreement among EPs was also assessed.

RESULTS

Five EPs with limited experience in nystagmus assessment volunteered to participate in the present study enrolling 98 patients. Their average evaluation time was 9.9 ± 2.8 min (range 6-17). Central acute vertigo was suspected in 16 (16.3%) patients. There were 13 true positives, three false positives, 81 true negatives and one false negative, with a high sensitivity (92.9%, 95% CI 70-100%) and specificity (96.4%, 95% CI 93-38%) for central acute vertigo according to senior audiologist evaluation. The Cohen's kappas of the first, second, third and fourth steps of the STANDING were 0.86, 0.93, 0.73 and 0.78, respectively. The whole test showed a good inter-observer agreement (k = 0.76, 95% CI 0.45-1).

CONCLUSIONS

In the hands of EPs, STANDING showed a good inter-observer agreement and accuracy validated against the local standard of care.

Missed strokes using computed tomography imaging in patients with vertigo: population-based cohort study

BACKGROUND AND PURPOSE

The purpose of this study was to determine the proportion of emergency department (ED) patients with a diagnosis of peripheral vertigo who received computed tomography (CT) head imaging in the ED and to examine whether strokes were missed using CT imaging.

METHODS

This population-based retrospective cohort study assessed patients who were discharged from an ED in Ontario, Canada, with a diagnosis of peripheral vertigo, April 2006 to March 2011. Patients who received CT imaging (exposed) were matched by propensity score methods to patients who did not (unexposed). If performed, CT imaging was presumed to be negative for stroke because brain stem/cerebellar stroke would result in hospitalization. We compared the incidence of stroke within 30, 90, and 365 days subsequent to ED discharge between groups, to determine whether the exposed group had a higher frequency of early strokes than the matched unexposed group.

RESULTS

Among 41 794 qualifying patients, 8596 (20.6%) received ED head CT imaging, and 99.8% of these patients were able to be matched to a control. Among exposed patients, 25 (0.29%) were hospitalized for stroke within 30 days when compared with 11 (0.13%) among matched nonexposed patients. The relative risk of a 30- and 90-day stroke among exposed versus unexposed patients was 2.27 (95% confidence interval, 1.12-4.62) and 1.94 (95% confidence interval, 1.10-3.43), respectively. There was no difference between groups at 1 year. Strokes occurred at a median of 32.0 days (interquartile range, 4.0-33.0 days) in exposed patients, compared with 105 days (interquartile range, 11.5-204.5) in unexposed patients.

CONCLUSIONS

One fifth of patients diagnosed with peripheral vertigo in Ontario received imaging that is not recommended in guidelines, and that imaging was associated with missed strokes.

Isolated vascular vertigo

Strokes in the distribution of the posterior circulation may present with vertigo, imbalance, and nystagmus. Although the vertigo due to a posterior circulation stroke is usually associated with other neurologic symptoms or signs, small infarcts involving the cerebellum or brainstem can develop vertigo without other localizing symptoms. Approximately 11% of the patients with an isolated cerebellar infarction present with isolated vertigo, nystagmus, and postural unsteadiness mimicking acute peripheral vestibular disorders. The head impulse test can differentiate acute isolated vertigo associated with cerebellar strokes (particularly within the territory of the posterior inferior cerebellar artery) from more benign disorders involving the inner ear. Acute audiovestibular loss may herald impending infarction in the territory of anterior inferior cerebellar artery. Appropriate bedside evaluation is superior to MRIs for detecting central vascular vertigo syndromes. This article reviews the keys to diagnosis of acute isolated vertigo syndrome due to posterior circulation strokes involving the brainstem and cerebellum.

Nystagmus-based approach to vertebrobasilar stroke presenting as vertigo without initial neurologic signs

BACKGROUND

We aimed to investigate the clinical courses and common nystagmus of isolated vertigo patients with vertebrobasilar stroke.

METHODS

The patients who presented with isolated acute spontaneous vertigo with spontaneous nystagmus (acute vestibular syndrome) at the Emergency Department were retrospectively analyzed. They were referred to the Otolaryngology Department due to the absence of neurologic signs or even of imaging abnormalities after the initial examination at the Emergency Department. Various clinical features, including presenting symptoms, delayed neurologic signs, the site of infarction, and videonystagmographic (VNG) findings were analyzed.

RESULTS

Of the 468 cases of acute vestibular syndrome, 23 (4.9%) cases of radiologically proven vertebrobasilar stroke were identified. Of the 23 patients, 17 (74%) showed aggravation of vertigo or delayed neurologic signs during the admission. In the analysis of VNG, 11 (48%) cases of direction-changing gaze-evoked nystagmus, 7 (30%) cases of fixation failure in the caloric test, 6 (27%) cases of periodic alternating nystagmus, and 4 (17%) cases of atypical head-shaking nystagmus were presented. Stroke occurred in the cerebellum (n=18, 78%), medulla (n=4, 17%), and pons (n=1, 4%).

CONCLUSION

In the early stage of vertebrobasilar stroke, an accurate diagnosis was difficult in the Emergency Department even though a radiologic study was performed, but various VNG abnormalities and delayed neurologic signs could help to diagnose whether the origin is central or not.

Very small cerebellar infarcts: integration of recent insights into a functional topographic classification

BACKGROUND

Very small cerebellar infarcts (diameter <2 cm) are a frequent finding on MRI. With an increasing scientific interest in cerebral microinfarcts, very small infarcts in the cerebellum deserve more of our attention as well. The goal of the present article was to review infarct terminology and mechanisms, as well as to critically appraise the current classification system for very small cerebellar infarcts.

METHODS

A search strategy was designed to identify all relevant studies on very small cerebellar infarcts in the English language. This search was restricted to papers published up to February 21, 2013. Studies were initially identified from the MEDLINE/PubMed database using the search terms 'small cerebellar infarct', 'lacunar infarct', 'microinfarct', 'end zone infarct', 'border zone infarct', 'watershed infarct', 'territorial infarct', and 'nonterritorial infarct'. Furthermore, a similar search strategy was directed to identify all relevant articles on (descriptive and functional) neuroanatomy and neuroimaging of the cerebellum.

RESULTS

Very small cerebellar infarcts have been referred to as lacunar infarcts, as junctional, border zone or watershed infarcts, as nonterritorial infarcts, as very small territorial or end zone infarcts, or simply as (very) small cerebellar infarcts. Since the original clinicoradiological study on these small infarcts, the classification into border zones remains in common use. This classification is based upon the assumption that these infarcts occur secondary to low flow in between arterial perfusion territories, where flow is believed to be the lowest. Later studies, however, have suggested occlusion of small (end-) arteries as a prerequisite for the pathogenesis of even small cerebellar infarcts, with low flow merely as a potential contributor. Therefore, it is likely that infarcts may as well occur in a nonborder zone distribution. Moreover, the classification into border zones may be considered unreliable since the location of border zones is highly variable among individuals and is not known in a particular patient. Recently, a functional topographic organization has been found in the cerebellum with evidence for a motor-nonmotor dichotomy between the anterior and posterior lobe. Since the cerebellar lobes can be easily and reliably distinguished with both CT and MRI, we recommend the classification of very small cerebellar infarcts according to topographic location.

CONCLUSION

There are several fundamental concerns with the current classification of very small cerebellar infarcts according to border zones, which we would like to overcome by recommending a new classification system based on topography. This will allow for a reliable and reproducible way of classifying very small cerebellar infarcts and is expected to improve clinicoradiological correlation.

Comparative sensitivity of computed tomography vs. magnetic resonance imaging for detecting acute posterior fossa infarct

BACKGROUND

Posterior fossa strokes, particularly those related to basilar occlusion, pose a high risk for progression and poor neurological outcomes. The clinical history and examination are often not adequately sensitive or specific for detection.

STUDY OBJECTIVES

Because this population stands to benefit from acute interventions such as intravenous and intra-arterial tissue plasminogen activator, mechanical thrombectomy, and intensive monitoring for neurologic deterioration, this study examined the sensitivity of non-contrast head computed tomography (NCCT) for diagnosing posterior fossa strokes in the emergency department.

METHODS

This study analyzed a prospectively collected database of acute ischemic stroke patients who underwent head NCCT within 30 h of symptom onset and who were subsequently found to have a posterior fossa infarct on brain magnetic resonance imaging (MRI) performed within 6 h of the NCCT.

RESULTS

There were 67 patients identified who had restricted diffusion on MRI in the posterior fossa. The National Institutes of Health Stroke Scale (NIHSS) scores ranged from 0 to 36, median 3. Only 28 patients had evidence of infarction on the initial NCCT scan. The timing of NCCT scans ranged from 1.2 to 28.9 h after symptom onset. The sensitivity of NCCT was 41.8% (95% confidence interval 30.1-54.4). The longest period of time between symptom onset and a negative NCCT with a subsequent positive diffusion-weighted imaging MRI was 26.7 h.

CONCLUSIONS

Head NCCT imaging is frequently insensitive for detecting posterior fossa infarction. Temporal evolution of strokes in this distribution, coupled with beam-hardening artifact, may contribute to this limitation. When a posterior fossa stroke is suspected and the NCCT is non-diagnostic, MRI is the preferred imaging modality to exclude posterior fossa infarction.

[Cerebellar infarction]

Cerebellar infarction can be difficult to diagnose because the clinical picture is often dominated by fairly non-specific symptoms, which are more indicative of a benign condition. When cerebellar infarction affects the brainstem, the semiology is richer, and pure cerebellar signs are rendered less important. A perfect knowledge of the organisation of the cerebellar artery territories is required, regardless of the infarct topography. This knowledge is essential for making an accurate diagnosis, understanding the mechanisms and organising a treatment plan. Clinical algorithms for the treatment of dizziness, headaches and vomiting would improve the selection of candidates for brain imaging. Thus, the early identification of patients with a high risk of subsequent deterioration would lead to a better prognosis in cases of cerebellar artery territory infarction.

Factors associated with misdiagnosis of acute stroke in young adults

Misdiagnosis or delayed diagnosis of acute ischemic stroke can result in neurologic worsening or a missed opportunity for thrombolysis. Because stroke in young adults is less common than stroke in the elderly, we sought to determine clinical characteristics associated with misdiagnosis of stroke in young adults. Patients from the prospectively maintained Young Stroke Registry in our comprehensive stroke center were reviewed. Demographic information, past medical history, presentation within the 3-hour time window, and outcomes were assessed. We compared patients misdiagnosed and those correctly diagnosed to identify factors associated with misdiagnosis of acute stroke. A total of 57 patients aged 16-50 were enrolled in the registry during 2001-2006. Eight patients (14%; 4 men and 4 women; mean age, 38 years) were misdiagnosed. Seven of these 8 patients were discharged from the emergency department initially. Patients age <35 years (P = .05) and patients with posterior circulation stroke (P = .006) were more likely to be misdiagnosed. All 8 misdiagnosed patients were initially evaluated at hospitals that were not certified primary stroke centers. Patients presenting with vertebrobasilar territory ischemia have a greater rate of misdiagnosis. Our study demonstrates the increasing need for "young stroke awareness" among emergency department personnel. Initial misdiagnosis can potentially lead to a lost opportunity for thrombolysis in otherwise good candidates.

The evidence base for the evaluation and management of dizziness

OBJECTIVES

Dizziness presentations pose many clinical challenges. The objective of this study is to broadly summarize the evidence base that supports clinical decisions in dizziness presentations.

METHODS

MEDLINE (1966 to September 2007), Web of Science and The Cochrane Library were searched for articles with clinical relevance on topics concerning dizziness. Additional sources were also searched for clinical practice guidelines. The following information was abstracted from each article: year of publication, journal type, type of article and the topics of the article.

RESULTS

Of nearly 3000 articles identified, 1244 articles met the inclusion criteria. The most common article type was a case report or case series, followed by expert opinion or review articles, studies of medical tests and clinical trials. Meta-analyses and systematic reviews were found on benign paroxysmal positional vertigo and Meniere's disease, but only a few other topics. No clinical practice guidelines were found that focus specifically on dizziness.

CONCLUSIONS

The evidence base for the evaluation and management of dizziness seems to be weak. Future work to establish or summarize evidence in clinically meaningful ways could contribute to efforts to optimize patient care and health care utilization for one of the most common presenting symptoms.

Value of computed tomography scans in ED dizziness visits: analysis from a nationally representative sample

OBJECTIVE

The study aimed to assess measures of the clinical value of computed tomography (CT) scans in dizziness presentations at the aggregate level.

METHODS

Using emergency department (ED) dizziness presentations captured in the National Hospital Ambulatory Medical Care Survey, the proportion of dizziness visits with a CT scan that received a central nervous system (CNS) diagnosis was measured yearly (1995-2004) and assessed for a trend over time. The independent association of having a CT scan with ED length of stay was examined using multivariable linear regression models.

RESULTS

The proportion of dizziness visits with a CT scan that received a CNS diagnosis dropped 62% from 1995 to 2004 (P < .05). By 2004, 94.1% (95% confidence interval, 89.4%-96.7%) of dizziness visits with a CT did not receive a CNS diagnosis. Having a CT scan was associated with a substantial increase in the length of stay with the effect modified by the number of other tests performed (range of increase, 40-77 minutes).

CONCLUSION

The clinical value of CT scans in dizziness presentations at the aggregate level may be very low and appears to have dropped over time. Computed tomography scans in the general dizziness population could also be an important contributor to ED length of stay. Use of CT scans in dizziness presentations should be a target for efforts to optimize the effectiveness and efficiency of care.

Vertigo and dizziness in the emergency department

Understanding three peripheral vestibular disorders--vestibular neuritis, benign paroxysmal positional vertigo, and Meniere's disease--is the key to the evaluation and management of vertigo and dizziness presentations in the emergency department. Each of these benign disorders is a common cause of a broad category of dizziness presentation. In addition, each of these disorders has characteristic features that allow for a bedside diagnosis. An effective strategy for "ruling-out" a serious disorder, such as stroke, is "ruling-in" a peripheral vestibular disorder. In this article a focus is on the key features of these disorders.

Dizziness presentations in U.S. emergency departments, 1995-2004

OBJECTIVES

The objectives were to describe presentation characteristics and health care utilization information pertaining to dizziness presentations in U.S. emergency departments (EDs) from 1995 through 2004.

METHODS

From the National Hospital Ambulatory Medical Care Survey (NHAMCS), patient visits to EDs for "vertigo-dizziness" were identified. Sample data were weighted to produce nationally representative estimates. Patient characteristics, diagnoses, and health care utilization information were obtained. Trends over time were assessed using weighted least squares regression analysis. Multivariable logistic regression analysis was used to control for the influence of age on the probability of a vertigo-dizziness visit during the study time period.

RESULTS

Vertigo-dizziness presentations accounted for 2.5% (95% confidence interval [CI] = 2.4% to 2.6%) of all ED presentations during this 10-year period. From 1995 to 2004, the rate of visits for vertigo-dizziness increased by 37% and demonstrated a significant linear trend (p < 0.001). Even after adjusting for age (and other covariates), every increase in year was associated with increased odds of a vertigo-dizziness visit. At each visit, a median of 3.6 diagnostic or screening tests (95% CI = 3.2 to 4.1) were performed. Utilization of many tests increased over time (p < 0.01). The utilization of computerized tomography and magnetic resonance imaging (CT/MRI) increased 169% from 1995 to 2004, which was more than any other test. The rate of central nervous system diagnoses (e.g., cerebrovascular disease or brain tumor) did not increase over time.

CONCLUSIONS

In terms of number of visits and important utilization measures, the impact of dizziness presentations on EDs is substantial and increasing. CT/MRI utilization rates have increased more than any other test.

Spectrum of dizziness visits to US emergency departments: cross-sectional analysis from a nationally representative sample

OBJECTIVE

To describe the spectrum of visits to US emergency departments (EDs) for acute dizziness and determine whether ED patients with dizziness are diagnosed as having a range of benign and dangerous medical disorders, rather than predominantly vestibular ones.

PATIENTS AND METHODS

A cross-sectional study of ED visits from the National Hospital Ambulatory Medical Care Survey (NHAMCS) used a weighted sample of US ED visits (1993-2005) to measure patient and hospital demographics, ED diagnoses, and resource use in cases vs controls without dizziness. Dizziness in patients 16 years or older was defined as an NHAMCS reason-for-visit code of dizziness/vertigo (1225.0) or a final International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis of dizziness/vertigo (780.4) or of a vestibular disorder (386.x).

RESULTS

A total of 9472 dizziness cases (3.3% of visits) were sampled over 13 years (weighted 33.6 million). Top diagnostic groups were otologic/vestibular (32.9%), cardiovascular (21.1%), respiratory (11.5%), neurologic (11.2%, including 4% cerebrovascular), metabolic (11.0%), injury/poisoning (10.6%), psychiatric (7.2%), digestive (7.0%), genitourinary (5.1%), and infectious (2.9%). Nearly half of the cases (49.2%) were given a medical diagnosis, and 22.1% were given only a symptom diagnosis. Predefined dangerous disorders were diagnosed in 15%, especially among those older than 50 years (20.9% vs 9.3%; P<.001). Dizziness cases were evaluated longer (mean 4.0 vs 3.4 hours), imaged disproportionately (18.0% vs 6.9% undergoing computed tomography or magnetic resonance imaging), and admitted more often (18.8% vs 14.8%) (all P<.001).

CONCLUSION

Dizziness is not attributed to a vestibular disorder in most ED cases and often is associated with cardiovascular or other medical causes, including dangerous ones. Resource use is substantial, yet many patients remain undiagnosed.

Overreliance on symptom quality in diagnosing dizziness: results of a multicenter survey of emergency physicians

OBJECTIVE

To assess emergency physicians' diagnostic approach to the patient with dizziness, using a multicenter quantitative survey.

PARTICIPANTS AND METHODS

We anonymously surveyed attending and resident emergency physicians at 17 academic-affiliated emergency departments with an Internet-based survey (September 1, 2006, to November 3, 2006). The survey respondents ranked the relative importance of symptom quality, timing, triggers, and associated symptoms and indicated their agreement with 20 statements about diagnostic assessment of dizziness (Likert scale). We used logistic regression to assess the impact of "symptom quality ranked first" on odds of agreement with diagnostic statements; we then stratified responses by academic rank.

RESULTS

Of the 505 individuals surveyed, 415 responded for an overall response rate of 82%. A total of 93% (95% confidence interval [CI], 90%-95%) agreed that determining type of dizziness is very important, and 64% (95% CI, 60%-69%) ranked symptom quality as the most important diagnostic feature. In a multivariate model, those ranking quality first (particularly resident physicians) more often reported high-risk reasoning that might predispose patients to misdiagnosis (eg, in a patient with persistent, continuous dizziness, who could have a cerebellar stroke, resident physicians reported feeling reassured that a normal head computed tomogram indicates that the patient can safely go home) (odds ratio, 6.74; 95% CI, 2.05-22.19).

CONCLUSION

Physicians report taking a quality-of-symptoms approach to the diagnosis of dizziness in patients in the emergency department. Those relying heavily on this approach may be predisposed to high-risk downstream diagnostic reasoning. Other clinical features (eg, timing, triggers, associated symptoms) appear relatively undervalued. Educational initiatives merit consideration.

Pitfalls in the diagnosis of cerebellar infarction

BACKGROUND

Cerebellar infarctions are an important cause of neurologic disease. Failure to recognize and rapidly diagnose cerebellar infarction may lead to serious morbidity and mortality due to hydrocephalus and brain stem infarction.

OBJECTIVES

To identify sources of preventable medical errors, the authors obtained pilot data on cerebellar ischemic strokes that were initially misdiagnosed in the emergency department.

METHODS

Fifteen cases of misdiagnosed cerebellar infarctions were collected, all seen, or reviewed by the authors during a five-year period. For each patient, they report the presenting symptoms, the findings on neurologic examination performed in the emergency department, specific areas of the examination not performed or documented, diagnostic testing, the follow-up course after misdiagnosis, and outcome. The different types of errors leading to misdiagnosis are categorized.

RESULTS

Half of the patients were younger than 50 years and presented with headache and dizziness. All patients had either incomplete or poorly documented neurologic examinations. Almost all patients had a computed tomographic scan of the head interpreted as normal, and most of these patients underwent subsequent magnetic resonance imaging showing cerebellar infarction. The initial incorrect diagnoses included migraine, toxic encephalopathy, gastritis, meningitis, myocardial infarction, and polyneuropathy. The overall mortality in this patient cohort was 40%. Among the survivors, about 50% had disabling deficits. Pitfalls leading to misdiagnosis involved the clinical evaluation, diagnostic testing, and establishing a diagnosis and disposition.

CONCLUSIONS

This study demonstrates how the diagnosis of cerebellar infarction can be missed or delayed in patients presenting to the emergency department.

Bilateral infarcts in the territory of the superior cerebellar artery: Clinical presentation, presumed cause, and outcome

BACKGROUNDS AND PURPOSE

The aim of this study was to document the clinical presentation, vascular topographic patterns, stroke mechanism, and outcome of bilateral infarcts in the territory of the superior cerebellar artery (SCA) based on data collected from a prospective acute stroke registry.

METHODS

We studied the clinical and radiological features of 11 patients with bilateral infarctions in the territory of the SCA diagnosed by brain MRI.

RESULTS

Bilateral SCA infarcts represented 23.4% (11/47) of all SCA territory infarction. Bilateral SCA infarcts mostly associated with brainstem (n = 5), cerebral (n = 5), or non-SCA cerebellar lesions (n = 4). The most common clinical presentation at onset was sudden fall with axial lateropulsion and dysarthria (n = 6). In five patients with a coexisting infarct(s) in the brainstem, limb weakness and/or mental change were prominent and often masked the signs of cerebellar dysfunction. Six patients showed no stenosis or occlusion in the vertebrobasilar system on brain MRA. Five had an obvious cardiac source of emboli. Eight patients showed favorable outcomes with complete recovery or minimal disability, but three patients with additional extensive brainstem infarcts died within 1 week.

CONCLUSIONS

Bilateral SCA territory infarcts show variable clinical, vascular topographic, and prognostic features. They usually result from cardiac emboli.

Infarto cerebelar: análise de 151 pacientes

Este estudo apresenta o tratamento de 151 pacientes com infarto cerebelar, sendo 98 homeNs (65%) e 53 mulheres (35%), com média de idade de 62,4 anos. Hidrocefalia obstrutiva foi diagnosticada em 7,9% dos pacientes associada com um infarto cerebelar extenso e em todos os 11 pacientes operados (7,2%). Quatro pacientes foram submetidos a derivação ventricular externa com 3 óbitos (75%) e 7 foram submetidos a craniectomia descompressiva suboccipital com 2 óbitos (28,5%). A mortalidade no grupo clínico foi de 15 pacientes (10,7%). Vertigem, vômito, sinal de Romberg e dismetria foram os sinais e sintomas de envolvimento cerebelar mais frequentemente observados. Infarto cerebelar devido a embolismo provocado por cirurgia cardiovascular ocorreu em 57 pacientes (37,7%).Infarto cerebelar como fato isolado ocorreu em 59 pacientes (39%) e infartos cerebelares associados a infartos de outras regiões ocorreram em 92 pacientes (61%). A ressonância magnética foi o melhor método para o diagnóstico das lesões, embora a tomografia pôde mostrar infarto cerebelar em 68 pacientes (78%).

Atherothrombotic cerebellar infarction: vascular lesion-MRI correlation of 31 cases

BACKGROUND AND PURPOSE

Correlation of MRI findings with atherosclerotic vascular lesions has rarely been attempted in patients with cerebellar infarction. The aim of this study was to correlate the MRI lesions with the vascular lesions seen on conventional cerebral angiography in cerebellar infarction.

METHODS

The subjects included 31 patients with cerebellar infarcts who underwent both MRI and conventional cerebral angiography. We analyzed the risk factors, clinical findings, imaging study, and angiography results. We attempted to correlate MRI lesions with the vascular lesions shown in the angiograms.

RESULTS

The vascular lesions seen on angiograms were subdivided into 3 groups: large-artery disease (n=22), in situ branch artery disease (n=6), and no angiographic disease with hypertension (n=3). The proximal segment (V1) lesions of vertebral artery were the most common angiographic features in patients with large-artery disease in which stroke most commonly involved the posterior inferior cerebellar artery (PICA) cerebellum. The V1 lesions with coexistent occlusive lesions of the intracranial vertebral and basilar arteries were correlated with cerebellar infarcts, which had no predilection for certain cerebellar territory. The intracranial occlusive disease without V1 lesion was usually correlated with small cerebellar lesions in PICA and superior cerebellar artery (SCA) cerebellum. The subclavian artery or brachiocephalic trunk lesion was associated with small cerebellar infarcts. The in situ branch artery disease was correlated with the PICA cerebellum lesions, which were territorial or nonterritorial infarct. No angiographic disease with hypertension was associated with small-sized cerebellar infarcts within the SCA, anterior inferior cerebellar artery, or SCA cerebellum.

CONCLUSIONS

Our study indicates that the topographic heterogeneity of cerebellar infarcts are correlated with diverse angiographic findings. The result that large-artery disease, in which nonterritorial infarcts are more common than territorial infarcts, is more prevalent than in situ branch artery disease or small-artery disease, suggest that even a small cerebellar infarct can be a clue to the presence of large-artery disease.

Isolated acute vertigo in the elderly; vestibular or vascular disease?

INTRODUCTION

Elderly patients with isolated acute vertigo are commonly encountered in clinical practice, but little is known about the underlying cause of the symptoms.

MATERIAL & METHODS

We prospectively studied 24 patients aged 50-75 years with the acute onset of isolated vertigo lasting > 48 h and no abnormality on neurological examination other than nystagmus. The study protocol included neuro-imaging (MRI 22 patients, CT 2 patients), Doppler sonography, and electro-oculography.

RESULTS

MRI/CT showed the presence of an infarction of the caudal cerebellum in six patients (25%), 3 of whom had a potential cardioembolic source and normal Doppler sonography findings, whereas 3 patients had ipsilateral vertebral artery occlusion and normal cardiac findings. MRI of the posterior fossa was normal in 18 patients. On electro-oculography, ataxic pursuit eye movements was a characteristic finding in patients with cerebellar infarction, whereas caloric test findings were not discriminative.

CONCLUSION

A caudal cerebellar infarction may easily be misdiagnosed clinically as a labyrinthine disorder, and was found to be the cause in one fourth of patients presenting with isolated acute vertigo.

Acute bilateral cerebellar infarction in the territory of the medial branches of posterior inferior cerebellar arteries

BACKGROUND

We describe the first clinicoradiological report of acute bilateral cerebellar infarction confined to the territory of the medial branches of the posterior inferior cerebellar arteries.

CASE DESCRIPTION

A 65-year-old man with atrial fibrillation and hypertension had sudden onset of vertigo, followed by brief loss of consciousness. Three days later a cranial computed tomographic scan showed acute hydrocephalus and low-density areas in the cerebellar vermis on both sides. On transfer the patient showed mild dysarthria, dysequilibrium with retropulsion, symmetrical bilateral horizontal gaze-evoked nystagmus on lateral gaze, and marked gait ataxia without brain stem signs, followed by marked vertigo that was induced by motion. Cranial magnetic resonance imaging revealed abnormalities consistent with fairly symmetrical bilateral cerebellar hemorrhagic infarction that was confined to the territory of the medial branches of the posterior inferior cerebellar arteries, in addition to minimal high-intensity areas in the pons on T2-weighted images. The patient improved with conservative therapy, including intravenous administration of glycerol.

CONCLUSIONS

We speculate that our patient likely had initial transient occlusion of the right vertebral artery at the origin of the right posterior inferior cerebellar artery, which probably gave rise to the bilateral medial branches of posterior inferior cerebellar arteries. This caused infarction in the territory of the medial branches on both sides without remaining brain stem signs. Such an unusual pattern of cerebellar infarction accompanied by acute hydrocephalus posed a diagnostic challenge at the time of transfer to our care, and correct diagnosis was facilitated by cranial magnetic resonance imaging.

Causes and mechanisms of territorial and nonterritorial cerebellar infarcts in 115 consecutive patients

BACKGROUND AND PURPOSE

Territorial cerebellar infarcts have mainly a thromboembolic mechanism. Cerebellar infarcts less than 2 cm in diameter have recently been reported as nonterritorial infarcts, but it is not clear whether they are low-flow or embolic infarcts. The aim of the present study was to compare the characteristics and causes of territorial and nonterritorial infarcts in a prospective series of 115 patients.

METHODS

We collected data from 115 consecutive patients with cerebellar infarcts (79 territorial and 36 nonterritorial [ie, less than 2 cm]), using magnetic resonance imaging (88 patients) and computed tomography.

RESULTS

Patients with territorial infarcts and those with nonterritorial infarcts had similar vascular risk factors and clinical presentations and an equal frequency of cardiac source of embolism (32% versus 42%; P = NS) and of large artery occlusive disease (23% versus 19%; P = NS). Occlusive lesions of large arteries at angiography occurred at the level of one cerebellar artery (5% versus 0%; P = NS) and proximal to the ostia of the cerebellar arteries (18% versus 19%; P = NS). Infarcts distal to occlusive lesions were subdivided into unilateral vertebral artery occlusive disease (presumed artery-to-artery embolic mechanism; 18% versus 5%; P = NS) and low-flow state distal to bilateral vertebral or basilar artery occlusion (presumed hemodynamic mechanism; 0% versus 14%; P = .004). Patients with nonterritorial infarcts had more frequent hypercoagulable state (17% versus 1.25%; odds ratio, 15.6 [95% confidence interval, 1.8 to 135]). For the remaining patients, the mechanism of the infarct was unknown (34% versus 22%; P = NS).

CONCLUSIONS

Cerebellar infarcts less than 2 cm in diameter (ie, nonterritorial) have the same high rate of embolic mechanism as territorial infarcts (47% versus 49%; P = NS), have more frequent hypercoagulable state, and sometimes have a hemodynamic mechanism.

Cerebellar infarction. Clinical and neuroimaging analysis in 293 patients. The Tohoku Cerebellar Infarction Study Group

BACKGROUND AND PURPOSE

We performed this multicenter study to explore the full spectrum of the clinical characteristics and neuroimaging findings of cerebellar infarction, including patients with mild to severe illnesses.

METHODS

We studied 293 consecutive patients with cerebellar infarction diagnosed by computed tomography and/or magnetic resonance imaging who were admitted to 36 hospitals during 5 years.

RESULTS

Cerebellar infarcts constituted 2.3% of the total patients with acute brain infarction. The backgrounds and risk factors were similar to those in patients with infarctions of the cerebral hemispheres. At least 24% were embolic, and the diagnosis of embolism could not be ruled out in 27%. Infarcts involving the superior cerebellar artery (SCA) region (52%) and the posterior inferior cerebellar artery (PICA) region (49%) were far more frequent than those involving the anterior inferior cerebellar artery (AICA) region (20%). Patients with SCA infarcts exhibited obtunded consciousness and ataxia more frequently than those with PICA infarcts (P < .05). Infarcts in the PICA regions were associated with abnormalities of the PICA (64%) or the vertebral arteries (57%), whereas infarcts in the SCA and AICA regions were associated with abnormalities in the SCA or AICA, respectively, in approximately 30% of patients, in the basilar artery in approximately 16%, and in the vertebral artery in more than 60% of patients. Outcomes were poorer with SCA infarcts than with AICA and PICA infarcts.

CONCLUSIONS

These data indicate similar frequencies of SCA and PICA infarcts and illustrate the difference in clinical presentation and outcomes between SCA and PICA infarcts. They also indicate that not only in situ thrombosis but also cardiogenic or artery-to-artery embolism and the insufficiency of collateral circulation play important roles in the pathogenesis of cerebellar infarction.