Gonzalo Alvarez

Incidence, 30-day case-fatality rate, and prognosis of stroke in Iquique, Chile: a 2-year community-based prospective study (PISCIS project)

BACKGROUND The epidemiology of stroke in Latin-American populations and variation of subtypes between communities are unclear. Our aim was to ascertain prospectively the incidence of first-ever stroke in the predominantly Hispanic-Mestizo population of Iquique, a city in the northern desert region of Chile. METHODS We prospectively identified all possible cases of stroke and transient ischaemic attacks between July 1, 2000, and June 30, 2002, from several overlapping sources. Patients were rapidly assessed by two field neurologists. Standard definitions for incident cases, stroke, transient ischaemic attack, pathological type, and infarction subtype were used. All cases identified were adjudicated by at least two stroke neurologists and followed up at 6 months. Incidence rates of first-ever strokes were calculated from the population of Iquique (214 526) according to the national census of 2002. FINDINGS Of 380 cases of stroke identified, 292 were incident. CT scans were done in 267 (91%) patients and the mean time to scan was 2.2 days. The hospital admission rate was 71% (207/292). The overall age-adjusted incidence rate of first-ever stroke was 140.1 per 100,000 (95% CI 124.0-156.2). The incidence rates per 100,000 according to pathological type were: infarcts 87.3, intracerebral haemorrhage 27.6, and subarachnoid haemorrhage 6.2. The 30 day and 6-month case-fatality rates were 23.3% and 33.0%, respectively. INTERPRETATION Our results show incidence rates of stroke similar to those reported in other community studies. Although the proportion of intracerebral haemorrhages was higher than reported in previous studies, the overall incidence was not, which could indicate a slightly lower incidence of ischaemic strokes in this population than in other countries. The prognosis was similar to that found in other population-based studies.

Incidence, case-fatality rate, and prognosis of ischaemic stroke subtypes in a predominantly Hispanic-Mestizo population in Iquique, Chile (PISCIS project): a community-based incidence study

BACKGROUND Incidence of ischaemic stroke subtypes, classified by cause, seems to vary between communities. We aimed to prospectively ascertain the incidence of first-ever ischaemic stroke in a predominantly Hispanic-Mestizo population in the northern desertic region of Chile. METHODS Between July, 2000, and June, 2002, all patients with possible stroke or transient ischaemic attacks were identified from multiple overlapping sources and were rapidly assessed by two field neurologists. All identified patients were diagnosed by at least two stroke neurologists according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) definitions and were followed up at 6 months. Annual incidence rates were age adjusted to WHO, European, and US populations by the direct method to allow comparisons. FINDINGS A total of 239 ischaemic strokes were identified, of which 185 (77%) were first-ever cases. 151 (82%) patients were hospitalised, of whom only 70 (38%) were assessed within 6 h of symptom onset. The mean age of patients was 66.4 years (SD 14.9) and 56% were men. The crude annual incidence rates (per 100 000) according to stroke subtype were: cardioembolic, 9.3; large-artery disease, 2.0; small-vessel disease, 15.8; other determined cause, 0.2; and undetermined cause, 17.4. Hypertension was the most common cardiovascular risk factor in all subtypes and atrial fibrillation was the most common cause of cardioembolic stroke. Case fatality at 30 days was highest in cardioembolic strokes (28%) and lowest in small-vessel disease (0%). Dependency or death at 6 months was also highest in cardioembolic strokes (62%) and lowest in small-vessel disease (21%). INTERPRETATION Incidence and prognosis of small vessel and cardioembolic infarction was similar to that in other populations and incidence of large-artery atherothrombotic infarction was lower than in most previous reports. Hypertension and atrial fibrillation were the most common risk factor and cause, respectively, of ischemic stroke in this population. These findings should help the national stroke programme in the prevention of cardioembolic stroke, increase access to specialists and acute brain imaging and vascular studies, and improve stroke care.

Incidence of Lobar and Non-Lobar Spontaneous Intracerebral Haemorrhage in a Predominantly Hispanic-Mestizo Population – The PISCIS Stroke Project: A Community-Based Prospective Study in Iquique, Chile

Background: The incidence of intracerebral haemorrhage (ICH) in Hispanics is high, especially of non-lobar ICH. Our aim was to ascertain prospectively the incidence of first-ever spontaneous ICH (SICH) stratified by localisation in a Hispanic-Mestizo population of the north of Chile. Methods: Between July 2000 and June 2002 all possible cases of ICH were ascertained from multiple overlapping sources. The cases were allocated according to localisation. Those with vascular malformations or non-identifiable localisations were excluded. Results: We identified a total of 69 cases of first-ever ICH. Of these, 64 (92.7%) had SICH, of which we allocated 58 cases (84%) to non-lobar or lobar localisation. The mean age was 57.3 ± 17 years, and 62.3% of the subjects were male. The age-adjusted incidence rates were 13.8 (non-lobar) and 4.9 (lobar) per 100,000 person-years. Non-lobar SICH was more frequent in young males and lobar SICH in older women. The non-lobar-to-lobar ratio was similar to previous findings in Hispanics. Hypertension was more frequent in non-lobar SICH and in diabetes, heavy drinking and antithrombotic use in lobar SICH, but in none significantly. There was no association between localisation and prognosis. Conclusions: The incidence of non-lobar SICH was high, but lower than in most non-white populations. This lower incidence could be due to a lower population prevalence of risk factors, a higher socioeconomic level in this population, or chance.

Effects of material deprivation on neurological functioning

An intellectual deficit in low socio-economic strata (S-E) of underdeveloped countries is widespread. A similar phenomenon is observed in industrialized countries and is known as socio-cultural retardation (S-CR); one theory holds that it is due to psychosensory deprivation whilst another denies that there is in fact a deficit, there being only middle class-oriented testing applied to subjects whose skills lie in another direction. Whichever theory is true, in underdeveloped countries the problem is compounded by malnutrition and perennial infection so that the intellectual deficit in these societies may be qualitatively different. This paper sets out the point of view of a clinical neurologist who believes it likely that the technological Western mode of life entails an organization of the brain which is lacking in subjects in low S-E strata of less sophisticated cultures. These will therefore evince multiple mild deficiencies in specific functions of the brain. The core is thought to be incomplete maturation of neural mechanisms. Examples are given: (1) facial dyspraxia; (2) permanence of primitive reflexes; (3) poor body image and sensory integration; and (4) tactile-perceptual functioning (which in fact showed no deficiency but is given as the type of neuropsychological factor which may show delay). Middle class life in Western society is held to be more complex in absolute terms. This is an important cause of the large number of dropouts from primary education in Latin America, whose school systems are based on middle class values, themselves tailored to the technological age.

Child-holding patterns and hemispheric bias: Evidence from pre-Columbian American art

Abstract Mothers prefer to hold their babies in their left arm in nearly all cultures, as shown by contemporary studies and studies of artwork throughout history. The current explanation is that there exists an instinctive attempt to recreate the fetal habitat by placing the childs head near to where the maternal heartbeat can be heard. An additional explanation is that the left-sided preferences is a manifestation of hemispheric dominance, since the right hemisphere is dominant for affective and attentive processes, thus making the left side the site of maximal attention. However, the intensity of left- sided preference appears to have change throughout historical time, as shown by studies of artwork; this ought not to be the case if the heartbeat theory alone held true, given that this is a constant. It is postulated here that hemispheric bias can shift from one side to another, and examples are given that are socioeconomic, linguistic, and of sexual orientation in nature might explain why at certain periods of historical time, the left- sided preference was stronger than in others. In this light, 71 pieces of pre-Columbian ceramics were studied; 37 were Mesoamerican (Mexico and Northern Central America) and 34 were Andean (Peru, Ecuador, and Columbia). Overall left-sided preference was 65%, without significant difference between the two cultures. However, the period roughly encompasses between 300 b.c. and 600 a.d. (accounting for 45 pieces—23 Mesoamerican and 22 Andean) and gives 83% left-side preference for Mesoamerica as against 54% for the Andean area, which is significantly different ( p

Differences in postural hypotension and ankle jerks in the elderly from two contrasting socio-economic levels

Subjects in low socio-economic strata in underdeveloped countries are subjected to considerable adverse influences which may enhance age-related changes in the nervous system. We therefore assessed the presence of ankle jerks and the degree of postural hypotension in two groups, one from the upper socio-economic level (58 subjects) and the other from the lower socio-economic level (56 subjects). All subjects were over 65 years of age. Only 6% had bilateral loss of ankle jerks, with no difference between the groups. Postural hypotension of 30 mmHg or greater was more frequent in the upper socio-economic group, nine out of 58 versus two out of 56 in the lower group. We conclude that there is no relationship in the elderly between social deprivation and certain markers of neurological dysfunction, such as the absence of ankle jerks and postural hypotension. The reasons for a greater frequency of postural hypotension in the higher socioeconomic group are unclear.

The neurology of poverty

An intellectual deficit is known to exist in populations where extreme poverty is rife and is thus seen extensively in the lower socio-economic strata of underdeveloped nations. Poverty is a complex entity whose sociological and economic indicators often bear little relevance to the biological agents which can affect the central nervous system. An attempt is made to express poverty in terms of identifiable defects, physiological in nature. Thus adverse socio-economic factors are converted into specific biological entities which, though necessary for adequate development of the brain, are restricted where there is poverty. A number of causative deficiencies, including nutritional, visual, auditory, tactile, vestibular, affective, and other stimuli are postulated. These interact and potentiate one another. Each is capable of an independent action on the brain and examples are given of some sensory deprivations as well as malnutrition and their possible mechanism of action. If the various deficiencies can independently harm the brain, then a number of separate specific functions should be affected; examples are offered. The nature of this intellectual deficit is probably a non-fulfillment of genetic potential of certain specific functions of the brain, which may exhibit limited variations between one community and another, depending on cultural differences. The deleterious effect of this intellectual impairment is seen most clearly in figures of school desertion, for example in Latin America. Analogous data for adults is scarce.

Análisis del cumplimiento de la Guía Clínica del AUGE en pacientes con accidente cerebrovascular isquémico: la utilización de tecnología sanitaria de diagnóstico para prevención secundaria en un hospital público

Background: Acute ischemic stroke in adults was given an Explicit Guarantee of diagnosis and treatment (GES) with Clinical Guidelines in 2007 as part of the on-going Chilean National Health Reform. Aim: To evaluate the adherence to official guidelines with regard to the use of diagnostic methods for patients with acute ischemic stroke during their stay in a public hospital. Patients and Methods: The study included a review of the medical records of 101 patients aged 70 ±13 years (49 males and 52 females) diagnosed with acute ischemic stroke and discharged within August and September of 2008 and 2009 from a public hospital. Three trained ob-servers independently determined the degree of dependency of patients at discharge using the Modified Rankin score. The completion of recommended diagnostic tests (electrocardiogram, carotid Doppler ultrasound and echocardiogram) as well as their overuse was evaluated. Results: Ten patients died before discharge, 38% were discharged with and 52% were discharged without disabilities. Nineteen percent of patients with a Modified Rankin score of two or less (corresponding to a slight disability) had a complete diagnostic workup, compared with 87% of patients with a score of 3 to 5 (moderate to severe disability). In 27% of the patients, there was an overuse of diagnostic tests. No association between the diagnostic test use adequacy and year of discharge was observed. Conclusions: There exists a disparity between the recommended diagnostic testing and the actual tests completed among patients with acute ischemic stroke.

Enseñanza de la neurología en el pregrado: propuesta de una nueva metodología

En opinion de los autores; para los medicos no neurologos la neurologia en nuestro pais es vista como un tema dificil, que presenta dificultades aun en el manejo de afecciones neurologicas sencillas. Esta actitud es observable en paises desarrollados tambien, aunque quizas no tan acentuadamente. La ensenanza de neurologia entre nosotros es deficiente, no solo porque no hay suficiente integracion entre neurociencia basica y neurologia clinica, sino porque la metodologia docente suele ser obsoleta, y se apoya mas en la memorizacion de contenidos que en aplicarlos. Se propone un metodo de ensenanza, nuevo para nuestro pais, que contiene tres vertientes: a. el metodo de la ensenanza basada en problemas para reemplazar a clases magistrales; b. uso de la consulta ambulatoria para ensenar la toma de anamnesis y examen semiologico en vez de la tradicional sala de hospitalizacion donde suele haber casos desusados o comprometidos de conciencia; c. se ensenara solo enfermedades prevalentes, dejando de lado afecciones emblematicas para neurologos tales como la siringomielia y las degeneraciones espinocerebelosas. Se ha estado conduciendo un estudio piloto en la Universidad de Valparaiso, donde se dara inicio formal al programa en 2004

Incidence of subarachnoid haemorrhage in the Aconcagua Valley, Chile: a community-based, prospective surveillance project

Background An epidemiological surveillance project was set up in Central Chile to detect cases of subarachnoid haemorrhage (SAH) and its incidence. Methods Community-based prospective surveillance project carried out between 1 July 2000 and 30 June 2003, in the Aconcagua Valley in Central Chile. The authors ascertained all possible cases using multiple overlapping sources. Incidence rates were age–sex-adjusted. Results The authors identified 33 first-ever cases; 19 were women. The mean age (SD, range) was 50.7 (17.9, 16 to 82). The incidence per 100 000 age–sex adjusted to the world population was 5.1 (4.4 men, 5.6 women). The 30-day case-death rate was 54.5% (95% CI 38.0 to 70.2), and the prehospital death rate 21.2% (95% CI 10.7 to 37.7). Conclusions The incidence rate in Aconcagua is notably similar to that reported previously in Northern Chile and lower than in many high-income western populations. The lower incidence rates found in these two Chilean populations might be due to their younger age. A trend towards a higher 30-day case-death rate found in Central Chile is possibly associated with its higher rurality and therefore lesser accessibility to preventive measures and medical care.