RESUMEN
BACKGROUND: To assess the influence of exposure to tobacco cigarette smoke on the eosinophil count and the frequency of apoptosis of eosinophils in the nasal mucosa of teenagers with perennial allergic rhinitis. METHODS: Fifty patients were evaluated (aged 10 to 19 years old): 25 patients with and 25 patients with no recent exposure to tobacco cigarette smoke, by means of The Global Youth Tobacco Survey and cotinine/creatinine ratio. After a clinical evaluation, all the patients replied to a validated questionnaire of the severity of nasal symptoms; then, a nasal sample was processed to identify the eosinophil count and the frequency of apoptosis of eosinophils. RESULTS: Patients with active exposure to tobacco cigarette smoke had higher eosinophil counts than patients with no exposure to the smoke. In the two groups, apoptosis of eosinophils in the nasal mucosa was scarce and no significant correlation was observed between the frequency/severity of the nasal symptoms and the eosinophil count. CONCLUSION: Teenagers with perennial allergic rhinitis and active exposure to tobacco cigarette smoke may show increased eosinophil counts in the nasal mucosa, which might not be related to apoptosis of eosinophils or to the frequency/severity of nasal symptoms.
Asunto(s)
Eosinófilos/inmunología , Mucosa Nasal/citología , Rinitis Alérgica Perenne/inmunología , Contaminación por Humo de Tabaco/efectos adversos , Adolescente , Análisis de Varianza , Apoptosis , Niño , Femenino , Humanos , Masculino , Rinitis Alérgica , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Adulto JovenRESUMEN
OBJECTIVE: To assess the influence of environmental exposure to tobacco smoke on the nasal symptoms and nasal resistance of young patients with perennial allergic rhinitis. DESIGN: Cross-sectional study. SETTING: Tertiary referral centre. PARTICIPANTS: Fifty patients were evaluated (aged 10-19 years old): 25 patients with and 25 patients without recent exposure to tobacco smoke (confirmed by cotinine/creatinine ratio). MAIN OUTCOMES MEASURES: After a clinical evaluation, all the patients replied to a validated questionnaire of the severity of the nasal symptoms. Then total nasal airway resistance was recorded by active anterior rhinomanometry. RESULTS: Patients with exposure to tobacco smoke had a larger total resistance than patients without exposure (t-test, P < 0.01). No significant correlation was observed between the total score of the questionnaire of nasal symptoms and the nasal resistance. CONCLUSIONS: In young patients with perennial allergic rhinitis, exposure to tobacco smoke can be related to increased nasal resistance, which may not be recognised by the report of nasal symptoms.
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Resistencia de las Vías Respiratorias/fisiología , Rinitis Alérgica Perenne/diagnóstico , Rinomanometría/métodos , Contaminación por Humo de Tabaco/efectos adversos , Adolescente , Niño , Estudios Transversales , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Humanos , Masculino , Estudios Prospectivos , Reproducibilidad de los Resultados , Rinitis Alérgica Perenne/fisiopatología , Adulto JovenRESUMEN
BACKGROUND: Patients with vestibular disease have an increased rate of reporting symptoms of depersonalisation/derealisation (DD) and similar symptoms can be provoked in healthy subjects during caloric vestibular stimulation. OBJECTIVE: To assess the relationship between DD symptoms in patients with peripheral vestibular disease and their ability to update orientation in the environment. METHODS: Sixty healthy subjects and 50 patients with peripheral vestibular disease completed a DD questionnaire (Cox and Swinson, 2002) and a General Health Questionnaire (GHQ)-12 (Goldberg and Williams, 1988). This was followed by a test of updating spatial orientation in which subjects were exposed to 10 manually driven whole body rotations of 45 degrees, 90 degrees or 135 degrees in a square room, which contained distinctive features on the walls, in such a way that the features and corners subtended 45 degrees with respect to the subject. After each rotation subjects reported which wall or corner they were facing. Estimation error was calculated by subtracting the reported rotation from the actual rotation. RESULTS: DD scores were significantly higher in vestibular patients than in healthy subjects (p<0.05, t test). In patients, the lowest symptom scores and the lowest estimation errors were found in those with a unilateral canal paresis without balance symptoms whereas the highest scores and largest estimation errors were found in those with bilateral vestibular loss (p<0.05, ANOVA). Across all patients, DD scores were related to estimation errors (adjusted r2 = 0.25, p<0.05, ANCOVA). CONCLUSIONS: Patients with peripheral vestibular disease have a deficit in the ability to update orientation on the environment and a high prevalence of DD symptoms, which may imply a high order effect of the vestibular impairment. Derealisation symptoms in vestibular disease may be a consequence of a sensory mismatch between disordered vestibular input and other sensory signals of orientation.
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Despersonalización/diagnóstico , Despersonalización/epidemiología , Enfermedades Vestibulares/epidemiología , Adulto , Anciano , Causalidad , Comorbilidad , Intervalos de Confianza , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y CuestionariosRESUMEN
OBJECTIVE: To assess counts of α4 and α7 nicotinic acetylcholine receptors in nasal polyps of adults with or without long-term exposure to cigarette tobacco smoke. METHODS: Twenty-two patients with and 22 patients without exposure to cigarette tobacco smoke participated in the study. After endoscopic polypectomy, the fragments of the nasal polyps were analysed by immunohistochemistry. RESULTS: Compared to patients with no exposure, patients with exposure showed higher counts of α4 and α7 nicotinic acetylcholine receptors (t-test, p 0.05). CONCLUSION: Exposure to cigarette tobacco smoke may induce increased counts of α4 and α7 nicotinic acetylcholine receptors in nasal polyps of adults, with lower counts in males than females without exposure to tobacco smoke.
Asunto(s)
Pólipos Nasales/química , Receptores Nicotínicos/análisis , Factores Sexuales , Contaminación por Humo de Tabaco/análisis , Receptor Nicotínico de Acetilcolina alfa 7/análisis , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pólipos Nasales/patología , Pólipos Nasales/cirugía , Contaminación por Humo de Tabaco/efectos adversosRESUMEN
The aim of this study was to assess the function of the utricle and horizontal semicircular canals in patients with type 2 diabetes mellitus receiving primary health care, with/without a history of falls. 101 patients with type 2 diabetes mellitus, 34 to 84 years old (26 with and 75 without a history of falls) and 51 healthy volunteers (40-83 years old) accepted to participate. They denied having a history of dizziness, vertigo, unsteadiness, hearing loss, or neurological disorders. None of them were seeking care due to sensory or balance decline. After a clinical evaluation and report of symptoms related to balance using a standardised questionnaire, lateral canal function was assessed by sinusoidal rotation at 0.16 Hz and 1.28 Hz (60°/sec peak velocity), otolith function was assessed by static visual vertical (average of 10 trials) and dynamic visual vertical during unilateral centrifugation (300°/sec at 3.5 cm) and static posturography was performed on hard/ soft surface with eyes open/closed. Compared to healthy volunteers, patients showed decreased responses to unilateral centrifugation, but similar responses to horizontal canal stimuli (independently of age, peripheral neuropathy or a history of falls) (ANCoVA p < 0.05) and a larger sway area with a lengthier sway path. Compared to patients with no falls, patients with falls had a higher female/male ratio and a higher frequency of score ≥ 4 on the questionnaire of symptoms related to balance, but similar age, body mass index and frequency of peripheral neuropathy. In patients with type 2 diabetes mellitus, receiving primary healthcare who are not seeking care due to sensory or balance decline, utricular function may be impaired even in the absence of horizontal canal dysfunction or a history of falls.
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Diabetes Mellitus Tipo 2/fisiopatología , Sáculo y Utrículo/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: To assess quality of life of children and teenagers with recurrent respiratory papillomatosis, according to the evidence of infection by human papillomavirus types 6 and 11, compared with healthy volunteers and patients with chronic otitis media. METHOD: Participants and their parents completed the Pediatric Quality of Life Inventory 4.0. RESULTS: Patients with recurrent respiratory papillomatosis and their parents reported lower quality of life than healthy subjects (p < 0.01), but similar quality of life to patients with chronic otitis media. Those with human papillomavirus type 11 showed the lowest scores among all participants (p < 0.05). CONCLUSION: Young Mexican patients with recurrent respiratory papillomatosis and their parents perceive a poor quality of life, and they may experience limitations in interactions with their peers. Infection by human papillomavirus type 11 may increase the impact of the disease on quality of life.
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Infecciones por Papillomavirus/psicología , Calidad de Vida , Infecciones del Sistema Respiratorio/psicología , Adolescente , Estudios de Casos y Controles , Niño , Enfermedad Crónica , Femenino , Papillomavirus Humano 11 , Papillomavirus Humano 6 , Humanos , Masculino , México , Recurrencia Local de Neoplasia/psicología , Otitis Media/psicología , Infecciones por Papillomavirus/virología , Padres/psicología , Recurrencia , Infecciones del Sistema Respiratorio/virología , Encuestas y CuestionariosRESUMEN
BACKGROUND: Depersonalisation is a subjective experience of unreality and detachment from the self often accompanied by derealisation; the experience of the external world appearing to be strange or unreal. Feelings of unreality can be evoked by disorienting vestibular stimulation. OBJECTIVE: To identify the prevalence of depersonalisation/derealisation symptoms in patients with peripheral vestibular disease and experimentally to induce these symptoms by vestibular stimulation. METHODS: 121 healthy subjects and 50 patients with peripheral vestibular disease participated in the study. For comparison with the patients a subgroup of 50 age matched healthy subjects was delineated. All completed (1) an in-house health screening questionnaire; (2) the General Health Questionnaire (GHQ-12); (3) the 28-item depersonalisation/derealisation inventory of Cox and Swinson (2002). Experimental verification of "vestibular induced" depersonalisation/derealisation was assessed in 20 patients and 20 controls during caloric irrigation of the labyrinths. RESULTS: The frequency and severity of symptoms in vestibular patients was significantly higher than in controls. In controls the most common experiences were of "déjà vu" and "difficulty in concentrating/attending". In contrast, apart from dizziness, patients most frequently reported derealisation symptoms of "feel as if walking on shifting ground", "body feels strange/not being in control of self", and "feel 'spacey' or 'spaced out'". Items permitted discrimination between healthy subjects and vestibular patients in 92% of the cases. Apart from dizziness, caloric stimulation induced depersonalisation/derealisation symptoms which healthy subjects denied ever experiencing before, while patients reported that the symptoms were similar to those encountered during their disease. CONCLUSIONS: Depersonalisation/derealisation symptoms are both different in quality and more frequent under conditions of non-physiological vestibular stimulation. In vestibular disease, frequent experiences of derealisation may occur because distorted vestibular signals mismatch with the other sensory input to create an incoherent frame of spatial reference which makes the patient feel he or she is detached or separated from the world.
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Despersonalización/etiología , Enfermedades Vestibulares/complicaciones , Enfermedades Vestibulares/psicología , Adulto , Anciano , Estudios de Casos y Controles , Despersonalización/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Índice de Severidad de la EnfermedadRESUMEN
To assess the frequency and clinical characteristics of meningocele and meningoencephalocele into the middle ear, at an otological referral center of Mexico city. After analyzing 586 recordings of middle ear surgery, we identified that 3 (0.5%) had defects of the tegmen timpani, 2 had brain abscesses (0.34%) and 1 had (0.17%) a facial palsy. Two of the patients with defects of the tegmen timpani had herniation of the intracraneal tissue. Case 1. A 38 year old woman with a history of bilateral chronic otitis media, with 2 surgeries in the left ear. She was seeking medical care because of right hearing loss. However, computed tomography and magnetic resonance showed a defect of the tegmen timpani with temporal lobe herniation in the left ear. Case 2 was a 46 year old woman with no history of ear disease, just high blood pressure. She was seeking medical care because of right hearing loss, vertigo and headache. The clinical evaluation suggested tissue in the middle ear and the computed tomography showed a defect of the tegmen timpani, meningocele was confirmed by surgery. In the 2 patients the clinical characteristics did not suggest herniation of intracraneal tissue as the first diagnosis. This show us the importance of an intended evaluation and image studies to make an early diagnosis.
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Instituciones de Atención Ambulatoria , Meningocele/etiología , Otitis Media/complicaciones , Otolaringología/métodos , Adulto , Niño , Enfermedad Crónica , Femenino , Pérdida Auditiva Conductiva/diagnóstico , Pérdida Auditiva Conductiva/etiología , Humanos , Masculino , Meningocele/diagnóstico por imagen , México , Persona de Mediana Edad , Otitis Media/diagnóstico por imagen , Derivación y Consulta , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos X , Perforación de la Membrana Timpánica/diagnóstico por imagen , Perforación de la Membrana Timpánica/etiologíaRESUMEN
BACKGROUND: Feelings of unreality have been provoked in healthy subjects undergoing stimulation of the semicircular canals, but no studies have assessed the influence of otoliths stimulation on depersonalization/derealization (DD) symptoms. OBJECTIVE: To assess DD symptoms during unilateral centrifugation in healthy adults. METHODS: 100 subjects participated in the study. They completed a standardized questionnaire of symptoms related to balance (Jáuregui-Renaud 2003), the 17-item Hamilton Depression Rating Scale, the Zung Instrument for Anxiety Disorders and the Cox & Swinson 28-item DD inventory. After unilateral centrifugation (300°/s at 3.5âcm), subjects completed the DD inventory again. RESULTS: Centrifugation provoked symptoms which subjects denied ever experiencing before. The items most frequently reported were "Body feels strange or different in some way" (56%) and "Time seems to pass very slowly" (55%). The DD total score was related to the score of symptoms related to balance and to the depression inventory with no influence from the general characteristics of the subjects or the responses to vestibular tests. The individual scores of symptoms of vestibular function and derealization were related to the report of the other DD symptoms. CONCLUSIONS: In healthy subjects, unilateral centrifugation provokes DD symptoms. The results support that distorted vestibular signals may create a misleading frame of reference which mismatch with the other senses, giving rise to 'unreal' perceptions.
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Despersonalización/psicología , Prueba de Realidad , Sáculo y Utrículo/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Ansiedad/psicología , Centrifugación , Depresión/psicología , Escolaridad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estimulación Física , Pruebas de Función Vestibular , Vestíbulo del Laberinto/fisiología , Adulto JovenRESUMEN
The influence of acute unilateral vestibular lesions on respiratory rhythm after active change of posture, was evaluated by comparing responses from patients with acute vestibular neuritis, with those from normal subjects with minor injuries other than vestibular (e.g. epistaxis, headache) and patients with chronic bilateral vestibular dysfunction. Respiratory movements of the thorax-abdomen were recorded during 5 minutes in supine position, 5 minutes of back-unsupported sitting and 5 minutes of upright stance. Compared to supine position, sitting-up induced different responses in each group (p < 0.05, ANOVA). The healthy subjects showed a consistent decrease in the mean respiratory frequency related to an increase of the expiration time, which was absent in patients with vestibular neuritis. Subjects with minor injuries showed the opposite changes of expiration time and inspiration time with no change of the respiratory frequency and patients with bilateral vestibular dysfunction showed a trend to increase their respiratory frequency. Standing-up did not evoke any further changes in any group. We conclude that the vestibular system modulates the respiratory response to reorientation of the head and trunk to upright position and this influence is reduced during the acute stage of a vestibular lesion.
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Lateralidad Funcional/fisiología , Postura/fisiología , Mecánica Respiratoria/fisiología , Neuronitis Vestibular/fisiopatología , Vestíbulo del Laberinto/lesiones , Enfermedad Aguda , Adulto , Enfermedad Crónica , Interpretación Estadística de Datos , Femenino , Humanos , Masculino , Posición Supina/fisiologíaRESUMEN
We evaluated the contribution of the semicircular canals to autonomic responses to rotation in 12 normal subjects and three labyrinthine defective patients. Respiration, heart rate, arterial blood pressure and blood flow in the finger were recorded during 60 degrees /s steps of constant velocity rotation. Rotation was performed in the dark about a vertical axis: (I) with head upright for yaw stimulation of horizontal canals; (II) head tilted chin down and rotated laterally to stimulate the vertical canals in both face-forwards and backwards directions. In normal subjects, rotation in the pitch plane elicited an increase in respiratory frequency due to a shortening of the time for expiration, whilst patients had inconsistent responses. We conclude that vertical semicircular canal activity exerts a regulatory drive on respiration in human subjects.
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Fenómenos Fisiológicos Respiratorios , Canales Semicirculares/fisiología , Vestíbulo del Laberinto/fisiología , Adulto , Presión Sanguínea , Femenino , Dedos/irrigación sanguínea , Cabeza , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Flujo Sanguíneo Regional , RotaciónRESUMEN
Computerised video-oculography and scleral search coils were used to record the horizontal, vertical and torsional binocular eye movements of human subjects exposed to roll oscillation at 0.4 Hz about earth-horizontal and earth-vertical naso-occipital axes in darkness. The stimuli provoked a dominant torsional ('ocular counter-rolling') response with a ratio of peak slow phase eye velocity to stimulus velocity which was not significantly different for earth-horizontal (0.39, SD 0.08) or earth-vertical axis orientations (0.40, SD 0.08). For all conditions the responses also had a head-vertical component which was disconjugate ('skew deviation'). The cumulative, vertical, slow phase divergence was 5.8 degrees, SD 1.3 degrees, about upright and 4.3 degrees, SD 0.6 degrees, when supine. This is the first demonstration that dynamic roll stimuli provoke a skew deviation in normal human subjects. At the frequency tested, the skew was driven by vertical semicircular canal stimulation.
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Fenómenos Fisiológicos Oculares , Canales Semicirculares/fisiología , Visión Binocular/fisiología , Adulto , Electrooculografía , Potenciales Evocados Somatosensoriales/fisiología , Ojo/inervación , Femenino , Humanos , Periodicidad , Anomalía Torsional , Grabación en VideoRESUMEN
Heart rate variability (HRV), blood pressure variability (BPV) and respiratory frequency were measured by power spectrum techniques in six normal humans (25-34 years old) and one labyrinthine-defective patient (33 years old) during cold (30 degrees ) vestibular caloric stimulation. Caloric stimuli were delivered intermittently for 2 min, under two different breathing conditions: (1) spontaneous breathing and (2) breathing paced with a metronome (0.25 Hz). During the spontaneous breathing condition, in the normal subjects, the caloric stimuli induced a significant increase in the absolute magnitude of the power spectrum density of the high frequency component (0.15-0. 40 Hz) of HRV and the total bandwidth (0.04-0.4 Hz) of mean BPV. These responses were related to a shift in the weighted average of the respiration frequency on the respiration spectrum, from a median value of 0.27 Hz (range, 0.17-0.29 Hz) during baseline to 0.31 Hz (0. 26-0.31 Hz) following caloric stimulation. This change was not observed in the labyrinthine-defective patient, who had weighted averages of 0.37 Hz and 0.34 Hz, respectively. No significant changes in the normalised units of the low frequency component (0. 04-0.15 Hz) or the high frequency component (0.04-0.4 Hz) of HRV and BPV were observed. During the paced breathing condition, no consistent effect on HRV or BPV was evident. For both breathing conditions, the proportions of HRV and BPV power linearly independent from respiration did not show any caloric-induced change. This study shows that caloric vestibular stimulation produces changes in HRV and BPV by modifying the respiratory pattern.
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Sistema Nervioso Autónomo/fisiología , Presión Sanguínea/fisiología , Pruebas Calóricas/efectos adversos , Frecuencia Cardíaca/fisiología , Estimulación Física/efectos adversos , Fenómenos Fisiológicos Respiratorios , Nervio Vestibular/fisiología , Vestíbulo del Laberinto/fisiología , Adulto , Sistema Cardiovascular/inervación , Frío/efectos adversos , Femenino , Humanos , Masculino , Pruebas de Función Respiratoria , Sistema Respiratorio/inervación , Enfermedades Vestibulares/fisiopatología , Nervio Vestibular/citología , Vestíbulo del Laberinto/citologíaRESUMEN
BACKGROUND: The purpose of the study was to investigate and follow the equilibrium performance of patients with chronic polyneuropathy using Dynamic Posturography (DP) and Randomized Perturbed Posturography (RPP). METHODS: Fourteen patients with chronic polyneuropathy, aged 53-83 years, were evaluated by clinical investigation, vibrametry, DP and RPP in a six-year follow-up. The patient group was compared to 14 healthy volunteers, aged 63-80 years. The DP comprises a sensory organization (SO) part in which the platform and visual surround are stable or referenced to the patient sway, with eyes open or closed. In a movement coordination (MC) part, the platform makes active movements. In RPP, the platform moves randomly in the anteroposterior direction. RESULTS: Comparison between the first and second study of the patient group showed decreased equilibrium scores under stable conditions and when vision was excluded. Compared with controls, the patients showed significantly lower scores in most of the SO test conditions except when the platform was sway referenced with stable surround; in the MC part, the patients showed prolonged muscular response latencies, and in the RPP, the patients showed increased sway areas. CONCLUSIONS: The results are further evidence that proprioception is probably the single most important sensory input for postural control in humans. Posturography proved to be an objective method to study and follow the equilibrium performance in patients with PN.
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Examen Neurológico , Equilibrio Postural/fisiología , Postura/fisiología , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas de Función VestibularRESUMEN
BACKGROUND: Our purpose was to determine the repeatability, after 2 weeks, of frequency domain measures of heart rate variability (HRV) during simple cardiovascular reflex tests. METHODS: Twenty healthy volunteers aged 29.3 +/- 2.5 years were assessed twice (at weeks 0 and 2). Continuous electrocardiogram and minute-to-minute blood pressure were recorded during spontaneous and metronome-paced breathing (0.2 Hz). Under paced breathing, two tests were performed: 1) active change of posture: 5 min supine position, 5 min seated upright, and 5 min standing up, and 2) cold pressor test: the right hand was immersed in cold water (5 degrees C) for 2 min. RESULTS: Paced breathing elicited a significant increase of the high-frequency (HF) component of HRV. This effect was repeatable on 95% of the subjects. Active change of posture induced a significant increase of the heart rate with an increase of the low-frequency/high-frequency ratio of HRV. Although repeatability was better for the response to being seated upright than for the response to being standing up, it was always higher than 90%. The cold pressor test induced a significant increase of the heart rate and blood pressure, but with variable changes on the HRV measurements (either a decrease or an increase). Repeatability of responses was evident for 95-100% of the subjects. Although repeatability of HRV measurements in the same subject during the tests was higher than 95%, coefficients of repeatability reflected large differences among the subjects. CONCLUSIONS: The results suggest that it is not advisable to use isolated HRV changes to interpret the response to simple cardiovascular reflex tests in groups of healthy subjects.
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Fenómenos Fisiológicos Cardiovasculares , Frecuencia Cardíaca/fisiología , Reflejo , Frío , Humanos , Postura , Valores de Referencia , RespiraciónRESUMEN
Upright posture requires rapid and effective circulatory and neurologic compensations to maintain blood pressure and consciousness. Although it has been recognized over the past 100 years or more that the act of standing may cause hypotension in patients with autonomic dysfunction, only recently several of the pathophysiologic mechanisms resulting in orthostatic intolerance have been discovered. In patients with orthostatic hypotension, failure of reflex vasoconstriction causes pooling of blood in the legs during standing. Not everyone with a postural blood pressure drop requires treatment, nor does everyone with posturally induced symptoms have orthostatic hypotension. This review will discuss current knowledge of a broad, heterogeneous group of disturbances in the autonomic nervous system, each of which is manifested by hypotension, orthostatic intolerance, and often syncope.
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Hipotensión Ortostática/diagnóstico , Hipotensión Ortostática/etiología , Humanos , Hipotensión Ortostática/terapia , Estados Unidos/epidemiologíaRESUMEN
Three normal human subjects were oscillated about their naso-occipital axis in a supine position at 0.4 Hz and 0.1 Hz, both in darkness and in the light with a structured fixation target. The same subjects were oscillated in roll about an upright position, at the same frequencies, in darkness; and also about axes directed 20 degrees and 40 degrees to the left and to the right of the midsagittal plane, at 0.4 Hz, in darkness. Three-dimensional binocular eye movements were recorded using video-oculography. All stimuli induced a predominantly torsional nystagmus with small disconjugate head-vertical (skew) and conjugate head-horizontal components. For roll oscillation, the torsional slow phase velocity gain was higher in the light and generally increased with the stimulation frequency. In darkness, only one subject had significantly higher torsional gains in the upright compared to the supine position (12% difference), suggesting that the otolith contribution to the roll response is minimal at the frequencies tested. The slow phase velocity gain of the skew increased with fixation in two subjects. but decreased in the third subject; these changes were related to changes in eye vergence. In the upright position, with oblique axes of rotation, the head-vertical eye movements were asymmetrical, with the outermost eye executing a larger amplitude movement. The disconjugate head-vertical eye movements observed can be explained by the pattern of vertical semicircular canal stimulation and their connections to the extraocular muscles. In humans, skewing of the eyes may compensate for the eccentricity of the foveae which lie in the temporal retina and undergo vertical translations in opposite directions when the eyes tort.
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Movimientos Oculares/fisiología , Membrana Otolítica/fisiología , Rotación , Canales Semicirculares/fisiología , Adulto , Oscuridad , Electrooculografía , Potenciales Evocados Somatosensoriales , Femenino , Gravedad Alterada , Humanos , Masculino , Postura/fisiología , Visión BinocularRESUMEN
OBJECTIVE: To compare the diagnostic value of pharmacological stimulation with sublingual isosorbide dinitrate and intravenous isoproterenol during tilt testing in patients with neurocardiogenic syncope and with a negative tilt test without pharmacological provocation. METHODS AND RESULTS: One hundred and twenty patients with a history of neurocardiogenic syncope (aged 15 to 77 years) and 50 healthy volunteers (aged 25 to 70 years) were prospectively submitted to head-up tilt (HUT). Those who did not develop syncope or presyncope during passive HUT for 30 minutes underwent repeated HUT with isoproterenol infusion at 4 microg/min (ISOP HUT), for 10 minutes, and, subsequently, were tilted after sublingual administration of 5 mg of isosorbide dinitrate (ISDN HUT) for another 12 minutes. ISDN HUT was always performed after ISOP HUT. Sensitivity and specificity of passive HUT were 41% (95% C.I. 32.9% to 51.0%) and 100%, respectively. Sensitivity of ISOP HUT was 51.4% (95% C.I. 39.2% to 63.6%) and specificity 70% (95% C.I. 55.4% to 82.1%) and for ISDN HUT were 70% (95% C.I. 57.9% to 80.4%) and 88% (95% C.I. 75.7% to 95.5%), respectively. The accuracy of ISDN HUT was significantly higher than the accuracy of ISOP HUT 77.5% (95% C.I. 68.9% to 84.6%). There were fewer side effects during ISDN HUT. CONCLUSION: Sublingual isosorbide dinitrate is at least as sensitive as isoproterenol to assess patients with suspected neurocardiogenic syncope and with a negative tilt test without provocation. The low rate of side effects and the higher accuracy of ISDN HUT, along with the simplicity of this challenge compared to ISOP HUT, suggest that sublingual isosorbide dinitrate should be preferred as a provocative agent to evaluate neurocardiogenic syncope after a negative passive tilt test.
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Agonistas Adrenérgicos beta , Isoproterenol , Dinitrato de Isosorbide , Síncope Vasovagal/diagnóstico , Pruebas de Mesa Inclinada/métodos , Vasodilatadores , Administración Sublingual , Adolescente , Agonistas Adrenérgicos beta/administración & dosificación , Adulto , Anciano , Intervalos de Confianza , Electrocardiografía Ambulatoria/efectos de los fármacos , Electroencefalografía , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Inyecciones Intravenosas , Isoproterenol/administración & dosificación , Dinitrato de Isosorbide/administración & dosificación , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Síncope Vasovagal/fisiopatología , Vasodilatadores/administración & dosificaciónRESUMEN
A technique was applied to assess vestibular sensation without reference to external spatial, position cues. The stimuli were stopping responses to velocity-steps of 90 deg/s in the dark. Subjects indicated their perceived angular velocity by turning a flywheel connected to a tachogenerator. Two separate experiments were conducted. In one, subjects were rotated in yaw about an earth-vertical axis before and after prolonged rotational or visual (optokinetic) stimuli. In the second experiment, subjects were rotated in roll supine, with either the head ('roll centred') or the feet ('roll eccentric') on the axis of rotation. The two aims of the paper were to (i) examine the effect of repetitive vestibular and optokinetic stimulation on the time constant of decay of vestibular sensation in yaw; (ii) to compare vestibular sensation responses to rotation in roll both with and without the addition of a Z-axis centrifugal force. The pre-habituation sensation response in yaw decayed exponentially with a median time constant of 12.8 s. The duration of the sensation responses were significantly reduced following both prolonged vestibular and optokinetic stimulation. The reduction in vestibular responses following prolonged visual and vestibular stimuli, 1) is likely to occur in velocity storage mechanisms mediating ocular and perceptual responses, 2) may represent a mechanism for reducing the disorientating consequences of visual-vestibular conflict and 3) supports the use of optokinetic stimuli as a treatment for vestibular patients. The time constant of the sensation responses in roll was shorter and not significantly influenced by head position: 5.7 s in the head-centred position compared to 4.7 s in the eccentric head position. Therefore, perceptual as well as ocular responses to rotation in roll are determined primarily by cupula dynamics and not influenced by velocity storage.
Asunto(s)
Habituación Psicofisiológica , Sensación/fisiología , Vestíbulo del Laberinto/fisiología , Adulto , Femenino , Humanos , Masculino , Valores de Referencia , Rotación , Visión Ocular/fisiologíaRESUMEN
OBJECTIVE: To assess the auditory and vestibular function in patients with diabetes. MATERIAL AND METHODS: We studied and followed for three years, 10 patients (6 females) of 20.6 years of age (SD 5.5 years), with insulindependent diabetes mellitus of 9.5 years (SD 3.7 years). The patients were selected for having peripheral neuropathy without prolipherative retinopathy and otologic disease or individual factors which could cause neurootologic symptoms. Their glomerular filtration rate and renal plasma flow were 150 mL/min (SD 50) and 543 mL/min (SD 113). RESULTS: Initially all patients had normal audiologic responses, including auditory brainstem responses, but had abnormally and simetrically diminished horizontal vestibulo-ocular responses. A year later one patient had vertigo and asymmetric vestibulo-ocular responses. In the third year, another patient showed similar abnormalities and a third one showed sensorineural hearing loss. CONCLUSION: Our results suggest that patients with insulindependent diabetes mellitus may suffer neuro-otological deterioration.