Differences in stroke subtypes among natives and caucasians in Boston and Buenos Aires.

BACKGROUND AND PURPOSE: Several issues regarding ethnic-cultural factors, sex-related variation, and risk factors for stroke have been described in the literature. However, there have been no prospective studies comparing ethnic differences and stroke subtypes between populations from South America and North America. It has been suggested that natives from Buenos Aires, Argentina, may have higher frequency of hemorrhagic strokes and penetrating artery disease than North American subjects. The aim of this study was to validate this hypothesis. METHODS: We studied the database of all consecutive acute stroke patients admitted to the Ramos Mejia Hospital (RMH) in Buenos Aires and to the Beth Israel Deaconess Medical Center (BIMC) in Boston, Massachusetts, from July 1997 to March 1999. Stroke subtypes were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. All information on patients (demographic, clinical, and radiographic) was recorded prospective to the assessment of the stroke subtype. RESULTS: Three hundred sixty-one and 479 stroke patients were included at RMH and BIMC stroke data banks, respectively. Coronary artery disease was significantly more frequent in BIMC (P:<0.001), whereas tobacco and alcohol intake were significantly more frequent in RMH (P:<0.001). Intracerebral hemorrhage (P:<0.001) and penetrating artery disease (P:<0.001) were significantly more frequent in the RMH registry, whereas large-artery disease (P:<0.02) and cardioembolism (P:<0.001) were more common in the BIMC data bank. CONCLUSIONS: Penetrating artery disease and intracerebral hemorrhage were the most frequent stroke subtypes in natives from Buenos Aires. Lacunar strokes and intracerebral hemorrhage were more frequent among Caucasians from Buenos Aires than Caucasians from Boston. Poor risk factor control and dietary habits could explain these differences.

Multiple simultaneous intracerebral hemorrhages: clinical features and outcome.

BACKGROUND: The simultaneous occurrence of intracerebral hemorrhages in different arterial territories is an uncommon clinical event. Its predisposing factors and pathophysiological mechanisms are not clearly defined. OBJECTIVE: To analyze the frequency, risk factors, clinical features, neuroimaging findings, and outcome of multiple simultaneous intracerebral hemorrhages (SIHs). PATIENTS AND METHODS: We studied all patients with acute stroke admitted to our hospital from July 18, 1997, through December 18, 1999. Multiple SIHs were defined as the presence of 2 or more intracerebral hemorrhages affecting different arterial territories with identical computed tomographic density profiles. Patients with a history of traumatic brain injury were excluded from this study. Diagnostic investigation included routine blood and urine tests, coagulation studies, a chest radiograph, electrocardiogram, 2-dimensional transthoracic echocardiography, and computed tomography of the head without contrast medium. Disability was assessed using the National Institutes of Health Stroke Scale and Modified Rankin Scale. RESULTS: Among 142 patients with hemorrhagic stroke, we found 4 (2.8%) with SIHs. All 4 patients had a history of uncontrolled arterial hypertension. We excluded other potential causes of multiple SIHs by using appropriate diagnostic tests. The most common clinical manifestations were headache and weakness. Localization of hematomas was supratentorial, except for one patient who had both infratentorial and supratentorial hemorrhages. The mean National Institutes of Health score on admission was 15 and the Modified Rankin Scale score was higher than 4 at 3 months. CONCLUSIONS: In our study, all patients with multiple SIHs had arterial hypertension and a poor outcome. Additional analytic studies, including new imaging techniques, can help to elucidate the association between arterial hypertension and multiple SIHs, risk factors, and underlying mechanisms of this clinical condition.

Catalepsy after stroke.

Catalepsy denotes a tendency to maintain postures. We prospectively looked for catalepsy in 216 acute stroke patients. We found five patients with cataleptic postures. They were seen on the nonparetic side in all cases. Other movement abnormalities seen in the catatonic syndrome were absent. CT scans of the head showed ischemic infarctions in the middle cerebral artery territory in the five cases. Cataleptic postures associated with hemispheric lesions due to stroke may be a more common phenomenon than is believed, and their mechanism remains to be elucidated.

Reliability of the NINDS Myotatic Reflex Scale.

The assessment of deep tendon reflexes is useful for localization and diagnosis of neurologic disorders, but only a few studies have evaluated their reliability. We assessed the reliability of four neurologists, instructed in two different countries, in using the National Institute of Neurological Disorders and Stroke (NINDS) Myotatic Reflex Scale. To evaluate the role of training in using the scale, the neurologists randomly and blindly evaluated a total of 80 patients, 40 before and 40 after a training session. Inter- and intraobserver reliability were measured with kappa statistics. Our results showed substantial to near-perfect intraobserver reliability, and moderate-to-substantial interobserver reliability of the NINDS Myotatic Reflex Scale. The reproducibility was better for reflexes in the lower than in the upper extremities. Neither educational background nor the training session influenced the reliability of our results. The NINDS Myotatic Reflex Scale has sufficient reliability to be adopted as a universal scale.

Activated protein C resistance in patients with arterial ischemic stroke.

BACKGROUND: Activated C protein resistance (APC-R) has recently been reported to be a common cause of thrombophilia; it may be acquired or caused by a genetic defect (factor V Leiden mutation). It is clear that there is an association between APC-R and venous thrombosis. It has been suggested that there is a possible relationship of APC-R with arterial ischemic stroke (IS), but case-control studies have not given enough clues for considering APC-R as a main risk factor. OBJECTIVES: To assess the incidence of APC-R in patients with IS of several ethiologies in Buenos Aires. PATIENTS AND METHODS: Seventy-two patients with IS were assessed for signs or symptoms of previous clinical thrombophilia and the presence of vascular risk factors (RF). They were searched for APC-R (COATEST, APC resistance-V, with a predilution of the samples) test. Determinations were carried out between 1 to 4 months after the ischemic episode. The plasma of 50 healthy control subjects (blood donors) was used as controls. RESULTS: None of the patients had signs of previous thrombophilia; 57 (79.2%) had RF for IS, and 3 (4.2%) had APC-R (all of them with RF). One subject in the control group (2%) showed a low APC response (1/50). The occurrence of APC-R among patients with stroke was not significantly higher when compared with the occurrence of APC-R among the control subjects. CONCLUSIONS: In the present series, the incidence of factor V Leiden related APC-R in the group with IS was similar to the healthy population. Other risk factors were associated in patients showing APC-R.

[Electrophysiological study of the variations in innervation of the hand muscles]. / Estudio electrofisiológico de las variaciones en la inervación de los músculos de la mano.

An electrophysiological study was carried out searching for variations in the innervation of the muscles of the hand. For this purpose a simple and non time-consuming technique was designed for stimulating the ulnar and median nerves at the elbow and wrist. Recordings were performed with surface electrodes at the abductor pollicis brevis, adductor digiti minimi and first dorsal interosseus muscles. Several anomalous innervation patterns of the intrinsic muscles of the hand were found, and the innervation of the first dorsal interosseus by the median nerve was the most frequent.

[Diagnosis and treatment of myasthenia gravis: study of an inpatient population]. / Diagnóstico y tratamiento de la myasthenia gravis: estudio de una población hospitalaria.

Between 1974 and 1987 we have examined 50 patients with the diagnosis of myasthenia gravis. Female preponderance (2.5: 1) was found. Also, it was observed that most of the patients were aged between 20 and 49 years. Beside the clinical examination, the following tests were performed: (1) edrofonium test, (2) supramaximal repetitive nerve stimulation, (3) serum acetylcholine antibodies titers and (4) intraperitoneal passive transference of patient's sera to mice and recording of meepp's amplitude in the phrenic-diaphragm preparation in vitro. These four tests gave positive values for myasthenia in 90 to 100% of the cases. Thymus radiological examination was carried out by pneumomediastinography, which proved to correlate with the histological picture of the gland, and computed tomography, which disclosed some discrepances with the histology. Treatment was based on anticholinesterase drugs, corticosteroids and thymectomy, being the corticosteroids the most valuable therapeutical tool. Nine patients treated with steroids disclosed transitory worsening of their signs and symptoms at very early stages after onset of corticosteroid therapy, 6 of them had a disfavorable course in their follow-up. This observation seem to have value in the early prognosis of the disease.

[Cerebral embolism of cardiac origin]. / Embolia cerebral de origen cardíaco.

We reviewed 538 charts of patients hospitalized with acute ischemic strokes between 1983 and 1991. The inclusion criteria for cardioembolism were: 1) sudden onset and maximal neurological focal deficit from the beginning, 2) brain CT showing an ischemic infarct, hemorrhagic infarct, or multiple infarcts, 3) cardioembolic sources demonstrated by echocardiography or heart catheterization, and 4) absence of stenotic-occlusive cerebrovascular disease. Sixty-nine patients (12.8%) filled the criteria for cardiogenic brain embolism. Cardiac sources were: 1) nonvalvular atrial fibrillation in 20 patients (29.0%), 2) rheumatic heart disease in 14 (20.3%), 3) nonischemic dilated cardiomyopathy in 13 (18.8%). Nine of these (69%) had cardiac involvement due to Chagas' disease, 4) ischemic heart disease in 11 (15.9%), and 5) other less common conditions such as bacterial endocarditis, mitral valve, and congenital heart malformation in 11 (15.9). Transient ischemic attacks preceding stroke occurred in 11 patients (15.9%), six patients had previous strokes, and 14 patients (20.3%) had silent infarcts. Early recurrence of embolism (three initial weeks) occurred in 5 patients (7.2%), and 28.6% of the patients had hemorrhagic transformation within this period. Taken together, our figures show that, although they are well in line with the current literature, nonischemic dilated cardiomyopathy is one of the main causes of cerebral embolism in our community. This reflects the presence of a regional factor, namely Chagas' disease.

[Hypophonia in lacunar stroke]. / Hipofonía en ictus lacunar.

INTRODUCTION: Hypophonia has been defined as a reduction in speech volume. It is an uncommon finding in acute stroke, mainly related to multiple deep infarcts. CLINICAL CASE: An 82 year old hypertensive woman was admitted to our hospital presenting acute right sided weakness and low speech volume. She was hypophonic and unable to yell. Language was fluent without paraphasic errors. A diffusion weighted magnetic resonance showed a small hyperintense lesion in the left corona radiata. No other lesions were detected. CONCLUSIONS: Although, the precise anatomic area involved in the brain has not been clearly precised yet, hypophonia may be also due to isolated lacunar affecting the penetrating arteries in the corona radiata. Further studies are necessary to better understand the nature and the prognosis of this phenomenon.

[Fluctuation in bilateral thalamic infarction: diffusion study using magnetic resonance]. / Fluctuación en infarto talámico bilateral: estudio con difusión por resonancia magnética.

INTRODUCTION: Bilateral paramedian thalamic infarcts are uncommon. The most frequent clinical manifestations are acute impairment of consciousness, oculomotor abnormalities and cognitive disturbances. A fluctuating course has not been previously reported. CLINICAL CASE: A 66 year-old woman with a past history of arterial hypertension and diabetes was admitted to our hospital presenting four episodes of decreased consciousness and vertical gaze paresis. Neurological examination between episodes was unremarkable. Diffusion-weighted magnetic resonance imaging revealed high-signal lesions in both paramedian thalamic areas. CONCLUSIONS: Fluctuating impairment of consciousness may be a clinical presentation of bilateral paramedian thalamic infarction. Atheromatous occlusion of the mouth of the paramedian thalamic penetrating artery is the most common cause. Neurological findings and diffusion-weighted images may help to define the extension and the underlying pathophysiological mechanism.

Southern Buenos Aires stroke project.

BACKGROUND: Ethnic differences and vascular risk factors are the major determinants of stroke subtypes. Nevertheless, specific data from undeveloped countries is difficult to obtain. Natives from South America may have a higher frequency of penetrating small vessel disease and hemorrhagic stroke. However, there are few studies in South America supporting these findings. OBJECTIVE: We analyze demographic, ethnic, risk factors, clinical characteristics, and stroke subtypes in all patients with acute stroke admitted to our hospital. METHODS: We studied all consecutive acute stroke patients admitted to the Ramos Mejia Hospital in Buenos Aires from 1997 to 1999. Our hospital serves a determined population of Southern Buenos Aires. Data were collected prospectively on patients' admission in a form especially designed for this study including vascular risk factors, clinical features, epidemiological characteristics, and neuroradiological findings. Stroke subtypes were determined according to the TOAST classification. RESULTS: Among 361 acute stroke patients, 31% had hemorrhagic stroke. It was more frequent among Natives (34%) than Caucasians (27%) (P<0.002). Ischemic stroke subtypes were as follows: 105 (42%) patients had lacunar, 31 (12%) atherosclerotic stroke, 53 (21%) cardioembolic infarction, and 16 (6%) other causes of stroke. Forty-five (18%) patients were classified as undetermined. Small vessel disease was higher among Caucasians (35%) than Natives (24%). CONCLUSIONS: Penetrating artery disease (42%) and intracranial hemorrhage (31%) were the most common stroke subtypes, being more frequent than reported in the literature. Natives had significantly higher frequency of hemorrhagic stroke than Caucasians.

Spinal reflex activity in patients with Duchenne, limb-girdle and myotonic muscular dystrophies

La actividad refleja espinal excitatoria e inhibitoria fue estudiada en pacientes con distrofia muscular del tipo Duchenne, de las cinturas y miotónica. Para ello se emplearon técnicas electrofisiológicas que permitieron conocer el comportamiento de las respuestas H y T y del período silente. A esto se sumó la investigación del coeficiente de excitabilidad de la motoneurona espinal alfa. Tanto en la forma de Duchenne como en la de las cinturas el comportamiento reflejo medular, medido a través de las respuestas H y T, sugirió el compromiso de la neurona motora alpha del asta anterior de médula. En los que padecían la forma miotónica, las mismas respuestas se mostraron igualmente alteradas; sin embargo, en este caso, las peculiaridades del comportamiento observado están, más probablemente, ligadas a la modificación anatómica que exhibe el huso neuromuscular en estos pacientes antes que con una lesión primaria de motoneurona. En los tres grupos el coeficiente de excitabilidad estuvo reducido, fundamentalmente en las formas de Duchenne y miotónica. Este hallazgo señala una cierta participación de la corteza cerebral motora en estas enfermedades. No se encontraron diferencias entre controles y probandos en relación al período silente, hecho que sugiró la indemnidad de los circuitos medulares inhibitorios en estos pacientes

Estudio eletrofisiologico de las variaciones en la inervacion de los musculos de la mano. / Electrophysiological study of the changes in hand muscles innervation

Para investigar las probables variaciones en la inervacion de los musculos intrinsecos de la mano y/o la anastomosis entre os nervios mediano y cubital, se estudiaron 24 manos, estimulando en forma percutanea a dichos nervios, registrandose en abductor pollicis brevis (APB), adductor digiti minimi (ADM) y primer interoseo dorsal (PID). Se hallo una frecuente inervacion del PID por el mediano. Se describe la tecnica utilizada, comentando incidencia, importancia y probable comportamiento em distintas patologias de las variaciones halladas

Evaluación clínica y electromiográfica del tratamiento con gangliosidos en polineuropatias / Clinical and electromyographical evaluation of the treatment with gangliosides in polineuropathies

Con el objeto de evaluar la acción de los gangliósidos en el tratamiento de polineuropatías de etiología alcobólica y diabética, se estudiaron 39 pacientes (21 alcobólicos y 18 diabéticos), divididos en dos grupos, a doble ciego: uno recibió 20 mg/día de gangliósidos, en dos ciclos de 20 días cada uno, y el otro fue tratado con placebo. Los pacientes fueron evaluados clínica y electromiográficamente antes de empezar el tratamiento y luego de cada ciclo. Tanto los parámetros clínicos como electromiográficos (velocidad de conducción motora y latencia distal) mostraron mejoría en el grupo tratado con gangliósidos. Esta mejoría fue estadísticamente significativa, comparada con el grupo placebo, para los parámetros electrofisiológicos

Hipertrofía musculorum vera: estudio de un caso / Hypertrophia musculorum vera: report of a case

Presentamos un varón de 16 años, blanco, quien consultó en nuestro Servicio por presentar importante hipertrofia muscular generalizada sin alteraciones de la fuerza muscular ni fenómeno miotónico. Los exámenes de laboratorio fueron normales. La evaluación endócrina descartó hipotiroidismo. El electromiograma mostró un patrón inespecífico sin miotonía y con velocidad de conducción nerviosa normal. En la biopsia de músculo se observó un aumento del tamaño transversal mayor de las fibras tipos I y II, más notable en estas últimas, con respecto a controles normales. Estos hechos nos hacen concluir que el presente caso constituye una "hipertrofia musculorum vera" cuyas características difieren de los reportados previamente

Marked heart involvement in Becker's type muscular dystrophy

La distrofia muscular tipo Becker se diferencia de la tipo Duchenne por ser de instalación más tardía, progresión lenta y pronóstico más favorable. Se presenta un paciente de 21 años, varón, que comenzó después de la pubertad con debilidad muscular, que evolucionó con lentitud sin llegar a comprometer sus tareas habituales. La sintomatología cardíaca fue la dominante del cuadro, falleciendo por insuficiencia cardíaca y tromboembolismo pulmonar. Los hallazgos clínicos, de laboratorio, electromiográficos, electrocardiográficos y anatomopatológicos confirmaron el diagnóstico de distrofia muscular tipo Becker con afectación cardíaca. Llama la atención el mayor compromiso del músculo cardíaco respecto del esquelético, hecho no referido en la literatura. Nos planteamos la posibilidad de estar frente a una forma de distrofia muscular diferente de la descripta por Becker