Arnold Hoppe

Stroke epidemiology, prevention, and management strategies at a regional level: Latin America and the Caribbean

Stroke is a major health problem in Latin American and Caribbean countries. In this paper, we review the epidemiology, aetiology, and management of stroke in the region based on a systematic search of articles published in Spanish, Portuguese, and English. Stroke mortality is higher than in developed countries but rates are declining. Population-based studies show variations in incidence of strokes: lower rates of ischaemic stroke and similar rates of intracranial haemorrhages, compared with other regions. A significant proportion of strokes in these populations can be attributed to a few preventable risk factors. Some countries have published national clinical guidelines, although much needs to be done in the organisation of care and rehabilitation. Even though the burden of stroke is high, there is a paucity of information for implementing evidence-based management. The Global Stroke Initiative, the WHO STEPS Stroke surveillance, and WHO-PREMISE projects provide opportunities for surveillance at institutional and community levels.

Accuracy of Transcranial Doppler Compared With CT Angiography in Diagnosing Arterial Obstructions in Acute Ischemic Strokes

Background and Purpose— Patients with acute ischemic stroke and intracranial arterial obstructions have a poor prognosis and a high probability of deteriorating at 24 hours. We aimed to evaluate the diagnostic accuracy of power motion mode Doppler (PMD-TCD) compared with CT angiography as standard in diagnosing intracranial arterial obstructions in patients presenting with ischemic stroke of <24 hours. Methods— Consecutive patients presenting with acute ischemic stroke to the emergency department underwent high-resolution brain CT angiography and PMD-TCD within a 6-hour difference. Results— A total of 100 patients were included. PMD-TCD demonstrated 34 intracranial occlusions and CTA 33. There were 6 false-positives and 4 false-negative diagnoses with PMD-TCD. PMD-TCD had a positive likelihood ratio of 13.7, a negative likelihood ratio of 0.19, sensitivity of 81.8%, and specificity of 94% for detecting an arterial occlusion in any specific artery. Results for the middle cerebral artery were: positive likelihood ratio 24.6, negative likelihood ratio 0.045, sensitivity 95.6%, and specificity 96.2%. For the anterior circulation, the results were: positive likelihood ratio 18.5, negative likelihood ratio 0, sensitivity 100%, and specificity 94.5%. For the posterior circulation, the results were: positive likelihood ratio >1000, negative likelihood ratio 0.42, sensitivity 57.1%, and specificity 100%. The post-test probability for any occluded artery when PMD-TCD was positive increased for any admission National Institutes of Health Stroke Scale score but was especially remarkable for National Institutes of Health Stroke Scale scores between 7 and 15 points. Conclusions— PMD-TCD is valid compared with CT angiography for the diagnosis of arterial occlusions in patients with acute ischemic stroke, especially in middle cerebral artery obstructions.

Pandemic influenza A (H1N1) 2009 with neurological manifestations, a case series.

Please cite this paper as: Noriega et al. (2010) Pandemic influenza a (H1N1) 2009 with neurological manifestations, a case series. Influenza and Other Respiratory Viruses 4(3), 117–120.

Exclusion Criteria for Intravenous Thrombolysis in Stroke Mimics: An Observational Study

BACKGROUND Stroke mimics (SMs) are frequent in emergency departments (EDs), but are treated infrequently with intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis. We aimed at identifying the factors that lead to the exclusion of SMs from thrombolytic therapy. METHODS Consecutive patients presenting to the ED between December 2004 and March 2011 with symptoms that suggested acute ischemic stroke were included. RESULTS Eight hundred forty-two patients were included in this study; 113 (13.4%) were considered SMs; these patients were younger (P = .01), more frequently diabetic (P = .001), arrived later to the ED (P = .03), had lower National Institutes of Health Stroke Scale scores (P < .001), and higher frequencies of negative diffusion-weighted imaging studies (P = .002). The most common causes of cases of SM were toxic metabolic disorders (n = 34 [30.1%]) and seizures (n = 22 [19.5%]). The most frequent cause of consultation was aphasia (n = 43 [37.6%]). SM patients had a total of 152 contraindications for rt-PA, with 34 (30%) patients having >1 contraindication. The most frequent of these were being beyond the therapeutic window for thrombolysis (n = 96) and having deficits not measurable by the National Institutes of Health Stroke Scale or very mild symptoms before the start of rt-PA (n = 37). Twenty-four (21.2%) patients had both contraindications simultaneously. Two patients (1.76%) in the SM group were candidates for rt-PA but did not receive this treatment because they or their family rejected it. Of 729 stroke patients, 87 (11.9%) did receive rt-PA. CONCLUSIONS SM patients frequently had exclusion criteria for systemic thrombolysis, the most frequent being presenting beyond the established thrombolytic window.

Accuracy of Diffusion-Weighted Imaging in the Diagnosis of Stroke in Patients With Suspected Cerebral Infarct

Background and Purpose— The accuracy of diffusion-weighted imaging (DWI) for the diagnosis of acute cerebral ischemia among patients with suspected ischemic stroke arriving to an emergency room has not been studied in depth. Methods— DWI was performed in 712 patients with acute or subacute focal symptoms that suggested an acute ischemic stroke (AIS), 609 of them with AIS. Results— DWI demonstrated a sensitivity of 90% and specificity of 97%, a positive likelihood ratio of 31 and a negative likelihood ratio of 0.1 for detecting AIS. The overall accuracy was 95%. Of those patients who demonstrated abnormal DWI studies, 99.5% were AIS patients, and of those patients with normal DWI studies 63% were stroke mimics. Conclusions— DWI is accurate in detecting AIS in unselected patients with suspected AIS; a negative study should alert for nonischemic conditions.

Validez del Doppler transcraneal en el diagnóstico de muerte encefálica

BACKGROUND The clinical diagnosis of brain death is complex. AIM To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. PATIENTS AND METHODS Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure>60 mmHg, body temperature over 35 masculine Celsius and complete absence of brainstem reflexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. RESULTS Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9%), the interval between both evaluations was less than one hour. The sensitivity, specificity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100% respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. CONCLUSIONS TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.

Transcranial Doppler in a Hispanic-Mestizo population with neurological diseases: a study of sonographic window and its determinants.

Between 5% and 37% of patients are not suitable for transtemporal insonation with transcranial Doppler (TCD). This unsuitability is particularly frequent in elderly females and non‐Caucasians. We aim to evaluate TCD efficiency in a mixed Hispanic population in Santiago, Chile and to determine whether factors associated with the presence of optimal windows depend exclusively on patient‐related elements. Seven hundred forty‐nine patients were evaluated with power mode TCD. Optimal temporal windows (TWs) included detection of the middle, anterior, posterior cerebral arteries and terminal carotid. The patients age and sex, the location of the examination, the time of day, whether the test was conducted on weekends and whether mechanical ventilation was used were recorded. Percentages of optimal windows were calculated. Examinations were deemed ideal if both TWs were optimal. TWs were obtained in 82% of cases. In univariate analyses, male sex (P < 0.001), an age below 60 years (P < 0.0001) and mechanical ventilation (P= 0.04) correlated with ideal TWs. Using logistic regression where dependent variable was a non‐ideal window only male sex odds ratio (OR) 2.3 (1.51–3.45) and age below 60 OR 13.8 (7.8–24.6) were statistically significant. Our findings indicate that Hispanic populations have detection rates for TWs similar to Europeans and are affected by patient‐related elements.

The Role of TCD in the Evaluation of Acute Stroke.

The additional information that transcranial Doppler (TCD) can provide as part of a multimodal imaging stroke protocol in the setting of hyper acute strokes has not been evaluated.

Transcranial Doppler as a Predictor of Ischemic Events in Carotid Artery Dissection.

We aim to evaluate clinical features and transcranial Doppler (TCD) elements, as predictors of the development of ischemic events (IEs) in patients suffering from spontaneous carotid arterial dissection without stroke (CCADW).

Nasolaryngoscopic validation of a set of clinical predictors of aspiration in a critical care setting.

BackgroundAspiration is frequent in patients with acute neurologic disorders and swallowing dysfunction. Its incidence in stroke, as high as 51%, increases mortality by up to 3 times. Pneumonia, its main complication, further increases morbidity, mortality, and patient care costs. The objective of this study was to evaluate a set of bedside predictors of aspiration [“wet voice,” 3-oz water swallow test, and cervical auscultation in an intensive care unit (ICU)] and compare them with nasolaryngoscopy as the gold standard. MethodsWe conducted a prospective, nonblinded study of bedside predictors of aspiration risks in 65 consecutive ICU patients with an acute neurologic disorder or a severe medical or surgical condition with decreased level of consciousness. ResultsEndoscopic aspiration was detected in 17 patients. Sensitivities for wet voice, 3-oz water swallow test, and cervical auscultation were 58.82%, 88.23%, and 82.35%; specificities were 78.26%, 62.50%, and 80.43%. Positive predictive values were 50%, 45.45%, and 60.86%, and negative predictive values were 83.72%, 93.75%, and 92.50%, respectively. Positive likelihood ratios were 2.70, 2.35, and 4.20, respectively. The association of 2 positive clinical predictors, wet voice and cervical auscultation or wet voice and 3-oz water swallow test, improved specificity to 92.85% and 84.61%, positive predictive values to 83.33% and 69.23%, and likelihood ratios to 10.76 and 5.85, respectively. ConclusionsBedside clinical predictors for aspiration risks are a useful screening tool for ICU patients presenting with risk factors for this complication.