Pablo Venegas F

Prevalencia de la ateromatosis carotídea en pacientes con enfermedad cerebro vascular oclusiva

Background: Hispanics have a greater incidence of stroke and prevalence of intracranial atherosclerosis than whites. Aim: To study the prevalence of extracranial atherosclerosis among patients admitted to a hospital with an ischemic stroke. Material and methods: A prospective study in stroke patients admitted to a Neurology ward in a University Hospital. All were subjected to a CT scan, carotid duplex-Doppler ultrasonographic examination with Doppler measurement of blood flow velocity, permeability and plaques. Cardiac emboli were searched with transthoracic and transesophagic echocardiography. Results: One hundred ten patients (39 women), aged 67.5±11.4 years old were studied. Stroke was atherothrombotic in 46 (41.8%), embolic in 30 (27.3%), lacunar in 27 (24.6%) and of other type in 7 (6.4%). Ninety two patients (84.4%) had high blood pressure, 38% had high cholesterol levels, 35% had a cardiac disease and 26% were smokers. Thirty five subjects (31.8%) had a normal carotid ultrasonography, 46 (41.8%) had mural plaques, 16 (14.5%) had multiple plaques without occlusion, 13 (11.8%) had a partial occlusion and 7 (6,4%) had a total occlusion. Logistic regression analysis disclosed no significant relationship between stroke types and carotid atherosclerosis. Age was the only significant predictor for carotid atherosclerosis. Conclusions: The prevalence of severe carotid atherosclerosis in this group of stroke patients was less than expected (Rev Med Chile 2001; 129: 161-5).

Ceguera secundaria a neuropatía óptica isquémica por una disección carotídea espontánea: Caso clínico

In young and middle age subjects, spontaneous carotid dissectionis an increasingly recognized cause of ischemic stroke. Their usual presentation is facial painwith a Horner syndrome and a contra lateral paresis. Blindness has been reported as apresenting symptom in only a few cases. We report a 50 years old man who presented withamblyopia in the left eye, without periocular pain. Fundoscopy showed papilledema and aperipapillar hemorrhage, compatible with an ischemic optic neuropathy. A magnetic resonanceangiography confirmed a left carotid dissection (Rev Med Chile 2003; 131: 1042-44).(

Estudio de correlación clínico-radiológica, sensibilidad y especificidad de ecotomografía transcraneana en enfermedad de Parkinson y otros trastornos del movimiento

Background: The detection of hyperechogenicity of the substantia nigra using trans cranial sonography can be predictive of the diagnosis of Parkinson Disease. Aim: To report an experience with transcranial sonography for the diagnosis of Parkinson disease. Material and Methods: One hundred sixteen patients with movement disorders were subjected to a transcranial sonograpy to detect the presence of hyperchogenicity of the substantia nigra and basal ganglia. Afterwards, two physicians, unaware of the results of the sonography, examined the patients and reached a clinical diagnosis. The concordance between ultrasound results and the clinical diagnosis was analyzed. Results: In 64 patients, a clinical diagnosis of Parkinson disease was reached. Of these, 52 patients had substantia nigra hyperechogenicity and in 12, it was normal. On the other hand ultrasound was normal in 42 of 43 patients without a clinical diagnosis of Parkinson disease. Therefore the sensitivity and specifi city of trans cranial ultrasound for the diagnosis of Parkinson disease was 81 and 97%, respectively. Conclusions: Transcranial sonography has a good sensitivity and specifi city for the diagnosis of Parkinson disease

Anartria o apraxia del habla progresiva

Se presentan dos casos de anartria progresiva, discutiendo la relacion o el diagnostico diferencial con la apraxia del habla progresiva. En ambos casos se trataba de mujeres mayores de 65 anos con un cuadro de perdida progresiva del lenguaje oral, con diparesia facial, lingual y velar, deterioro cognitivo de tipo frontal y discretos signos piramidales. Las imagenes cerebrales estructurales fueron normales. Uno de ellos pudo corresponder a una paralisis supranuclear progresiva, la otra a una degeneracion corticobasal. Se analiza la literatura, llegando a la conclusion de que existen una serie de cuadros que pueden presentarse con un sindrome pseudobulbar progresivo. El diagnostico definitivo debiera ser patologico.

Consideraciones sobre las complicaciones motoras y neurotoxicidad de la levodopa en la enfermedad de Parkinson

Resumen es: Desde la introduccion de la levodopa para el manejo de la enfermedad de Parkinson esta ha sido el tratamiento estandar de esta enfermedad. La aparicion d...

Estudio de biodisponibilidad comparativa de dos formulaciones de risperidona existentes en el mercado chileno

Background: Bioavailability of a particular drug can vary according to the formulation used. Therefore, studies of comparative bioavailability of different formulations of a same drug are worthwhile. Aim: To compare the bioavailability of two risperidone formulations available in the Chilean market. Material and methods: The bioavailability of a local risperidone formulation (Spiron®) was compared with the original formulation of the drug (Risperdal®) in 12 healthy volunteers, aged 19±1 years. A single dose of 3 mg was given orally, using a randomized double blind protocol in two periods. Fifteen blood samples were obtained at regular intervals, until 24 h after drug administration. Risperidone plasma levels were measured by high pressure liquid chromatography. Pharmacokinetic parameters were calculated using a computer program that is independent of compartmental analysis. Results: The area under the curve of plasma concentration versus time, from 0 to infinite (ABC0-∞) and from 0 to 24 h (ABC0-24), early exposure (ABC from 0 to maximal time) and maximal plasma concentrations were significantly lower for Spiron®. Half life time and time to achieve the maximal concentration were similar for the two formulations. Conclusions: According to bioequivalence tests suggested by the Food and Drug Administration (FDA) of the United States (90% confidence interval for the difference of log transformed mean pharmacokinetic parameters), the formulations Risperdal® and Spiron®, cannot be considered interchangeable (Rev Med Chile 2003; 131: 527-34).

Temblor esencial: Una revisión crítica

Essential tremor is commonly considered as a benign and high prevalence disease; however its study is not systematized even in its definition. Methods: We di...

Afasia progresiva fluente: ¿Una forma de presentación inicial de demencia semántica?

Se presenta el caso de un hombre de 57 anos que presenta un cuadro degenerativo con afasia fluente y moderadas alteraciones de conducta, sin defecto semantico significativo, agnosia visual ni agrafia lexical y su estudio imagenologico cerebral. Se discuten los conceptos de afasia progresiva fluente y demencia semantica, concluyendo que la primera puede evolucionar hacia esta ultima. Nuestro caso se encontraria en esta situacion. Se senala que la patologia de las afasias progresivas es variable, siendo lo mas frecuente una degeneracion frontotemporal (con o sin inclusiones de proteina tau); con menor frecuencia corresponde a una enfermedad de Alzheimer o una degeneracion corticobasal

Piridoxina en el manejo de Disquinesias Tardías: Un estudio placebo controlado, randomizado, doble ciego y cruzado

Las Disquinesias tardias son reacciones adversas frecuentes e invalidantes de aquellos farmacos relacionados con la transmision dopaminergica. Una proporcion importante de pacientes que la padecen no responden a las terapias actualmente vigentes. En este estudio se randomizo a 28 pacientes portadores de Disquinesias tardias severas y refractarias a tratamiento habitual, provenientes del Instituto Psiquiatrico de Santiago, en dos grupos que recibieron Piridoxina (500 mg al dia) o placebo por 4 semanas, siguiendo un periodo de lavado de 7 dias tras los cuales ambos grupos se cruzaron, manteniendo tratamiento por 4 semanas adicionales. Se utilizo la escala AIMS (Abnormal Involuntary Movement Scale) para evaluar a cada paciente en la semana 2 y 4 de cada etapa del estudio. La Piridoxina fue bien tolerada y no hubo efectos adversos en el periodo de estudio, no encontrandose diferencias significativas en la mejoria de Disquinesias Tardia entre los grupos que recibieron Piridoxina o Placebo

Bioequivalencia entre dos formulaciones de claritromicina en suspensión pediátrica existentes en el mercado chileno

Se realizo un estudio comparativo de biodisponibilidad, para evaluar la bioequivalencia entre dos formulaciones de claritromicina en suspension de 250 mg/5 mL, una nacional (Pre-ClarO), y el innovador del mercado (KlaricidO). En ambos casos, se administro una dosis de 500 mg. Se utilizo un ensayo microbiologico para determinar las concentraciones plasmaticas del antimicrobiano. El ensayo esta basado en la correlacion entre la inhibicion del crecimiento bacteriano y la concentracion plasmatica de claritromicina. Un total de 12 voluntarios, jovenes sanos, participaron y completaron el protocolo del estudio, el cual fue aprobado por el Comite de Etica de la Facultad de Medicina de la Universidad de Chile. Los parametros farmacocineticos de concentracion plasmatica maxima (Cmax), tiempo de vida media (t1/2), area bajo la curva concentraciones plasmaticas versus tiempo, desde cero a infinito (ABC0-¥) y la constante de velocidad de absorcion (Kabs), no mostraron diferencias estadisticamente significativas entre los productos utilizados. De acuerdo a los criterios recomendados por la FDA y sobre la base de nuestros resultados, se concluye que las formulaciones en suspension pediatrica de 250 mg/5 mL Pre-Clar® y Klaricid® son bioequivalentes asumiendose que tendran igual eficacia clinica.