Falla autonómica asociada a hipoglucemia / Hypoglycemia associated autonomic failure

La hipoglucemia inadvertida (HI) es una complicación del tratamiento de la diabetes mellitus tipo 1 (DM1) y DM2 tratada con insulina o sulfonilureas, que se caracteriza por una capacidad reducida para percibir el inicio de los episodios de hipoglucemia. En general, coexiste con una insuficiente respuesta hormonal contrarreguladora a la hipoglucemia denominada falla autonómica asociada a la hipoglucemia (FAAH). El desarrollo de HI y de falla contrarreguladora a la hipoglucemia aumentan significativamente el riesgo de hipoglucemias severas. Se han desarrollado escalas de puntuación para identificar, en la consulta clínica, a este grupo de personas con elevado riesgo de hipoglucemias severas. La piedra angular del tratamiento consiste en evitar las hipoglucemias mediante una intervención multifactorial de cuidados clínicos y educación estructurada.

Hypoglycemia unawereness is a complication of type 1 diabetes treatment and of type 2 diabetes treatment treated with insulin or sulfonylureas, characterized by a reduced ability to perceive the onset of episodes of hypoglycemia. In general, it coexists with an insufficient counterregulatory hormonal response to hypoglycemia called: hypoglycemia associated autonomic failure (HAAF). The development of hypoglycemia unawereness and counterregulatory failure to hypoglycemia significantly increase the risk of severe hypoglycemia. Scoring scales have been developed to identify this group of people at high risk of severe hypoglycemia in the clinic. The cornerstone of treatment is to avoid hypoglycemia through a multifactorial intervention of clinical care and structured education.

Análisis del componente rápido de la cinética de recuperación del consumo de oxígeno tras un programa HIIT de 10 días en un grupo de obesos / Analysis of the fast component of the oxygen uptake kinetics after a 10 day long HIIT program in a group of obese men

Resumen Introducción: El sujeto obeso evidencia una disminución de la capacidad funcional (CF), que entre otros factores comprende una cinética del consumo de oxígeno (VO2) más lenta, asociada a una posible relación entre el tejido adiposo y una desregulación crónica del sistema nervioso autónomo, tanto en condiciones de reposo como de ejercicio. Objetivo: Analizar el comportamiento del tau rápido de la cinética off del consumo de oxígeno, luego de la aplicación de un protocolo de ejercicio interválico de alta intensidad y corta duración (HIIT) en un grupo de obesos. Metodología: Se diseñó un estudio comparativo, experimental y longitudinal de corto plazo en cinco sujetos obesos seleccionados por un muestreo no probabilístico intencionado. Se valoraron las siguientes variables: peso, talla, índice de masa corporal (IMC), perímetro de cintura, cinética del consumo de oxígeno y aquellas dependientes del procedimiento. Los datos de VO2 v/s tiempo se ingresaron al Software Graph Pad Prism 6, (Graph Pad Prism versión 6.01 para Windows®) donde se depuraron promediando intervalos de 10 segundos y fueron ajustados a un modelo de función bi-exponencial. Posteriormente se realizó un análisis estadístico descriptivo por medio del Software SigmaPlot 12.5 para Windows® usando las siguientes estadísticas de resumen: media, desviación estándar y rango. Resultados: La edad media fue 25,13 ± 0,62 años. La mayor variación al analizar los resultados en ambas fases del estudio (pre-intervención: 43,09 ± 7,78 s; post-intervención: 26,85 ± 3,78 s) se encontró en el tau rápido del VO2 (p= 0,034). Conclusiones: El entrenamiento de alta intensidad y corta duración realizado en un período de 10 días logra un efecto positivo sobre el componente rápido de la cinética off del VO2 para la población estudiada, mejorando así el tiempo de recuperación posterior al esfuerzo físico.

Abstract Introduction: Obese subjects exhibit a decreased functional capacity (FC) which, among other factors, entails a slower oxygen uptake kinetics associated to a pathological relationship between the adipose tissue and a chronically-deregulated autonomic nervous system, both in resting and exercise conditions. Objective: To analyze the fast-tau behavior of the oxygen consumption off-kinetics, after applying a high intensity and short duration intervallic exercise protocol (HIIT) in a group of obese men. Methodology: An exploratory, comparative, experimental and longitudinal short-term study of 5 obese subjects, selected by intentional non-probabilistic sampling, was designed. Weight, height, body mass index (BMI), waist circumference, kinetics of oxygen consumption and variables related to the procedure were assessed. Data from VO2 v/s time were compiled with Graph Pad Prism v. 6.01 by averaging 10-second intervals and fitted as a bi-exponential model. Subsequently, a descriptive statistical analysis was performed using SigmaPlot v. 12.5, calculating means, standard deviations and ranks. Results: Mean age was 25.13 ± 0.62 years. Highest variation when analyzing the results, in both phases of the study (pre-intervention: 43.09 ± 7.78 s; post-intervention: 26.85 ± 3.78 s), was found in the fast VO2 tau (p=0.034). Conclusion: The high-intensity, short-duration training performed over a 10-day period, achieves a positive effect on the rapid kinetic component of VO2 for the studied population, improving recovery time after physical exertion.

Avaliação diagnóstica da insuficiência autonômica / Diagnostic evaluation of autonomic failure

A síncope postural é uma perda transitória da consciência secundária à redução do fluxo sanguíneo cerebral e normalmente ocorre durante a ortostase. Transtornos do controle da homeostase circulatória sãofrequentemente incapacitantes e de difícil tratamento. O reconhecimento dos vários subgrupos de insuficiênciaautonômica é útil na definição do tratamento mais apropriado da desordem específica do paciente. Em conjunto com a síncope reflexa, a hipotensão ortostática (por insuficiência autonômica ou secundária a uma afecção crônica) responde pelas principais categorias fisiopatológicas de síncope postural. A incapacidade de identificar a causa subjacente da síncope pode resultar em aumento da morbidade, redução da qualidade de vida e aumento dos custos com os cuidados de saúde. Uma história clínica direcionada, associada a exame físico e eletrocardiografia, pode diagnosticar a maioria dos transtornos de controle circulatório. Em casos mais complexos, a análise do sistema nervoso simpático e as respostas circulatórias durante o teste de inclinação podem auxiliar no diagnóstico diferencial...

Postural syncope is a transient loss of consciousness secondary to a reduction in cerebral blood flow and is typically precipitated by standing. Disorders of circulatory homeostasis are frequently disabling and difficult to treat. Recognizing the various subgroups of autonomic insufficiency is helpful to choose the treatment that is bestsuited for the patient’s specific disorder. Along with reflex syncope, orthostatic hypotension (due to autonomicfailure or secondary to chronic disease) is responsible for the main pathophysiological categories of posturalsyncope. Failure to identify the underlying cause of postural syncope may result increased morbidity, impairedquality of life and increase in healthcare costs. With a detailed clinical history in addition to physical examination and electrocardiography, most circulatory control disorders may be diagnosed. In more complex cases, the analysisof the sympathetic nervous system and circulatory responses during head-up tilting can support the differentialdiagnosis...

Autonomic Function Tests: Some Clinical Applications

Modern autonomic function tests can non-invasively evaluate the severity and distribution of autonomic failure. They have sufficient sensitivity to detect even subclinical dysautonomia. Standard laboratory testing evaluates cardiovagal, sudomotor and adrenergic autonomic functions. Cardiovagal function is typically evaluated by testing heart rate response to deep breathing at a defined rate and to the Valsalva maneuver. Sudomotor function can be evaluated with the quantitative sudomotor axon reflex test and the thermoregulatory sweat test. Adrenergic function is evaluated by the blood pressure and heart rate responses to the Valsalva maneuver and to head-up tilt. Tests are useful in defining the presence of autonomic failure, their natural history, and response to treatment. They can also define patterns of dysautonomia that are useful in helping the clinician diagnose certain autonomic conditions. For example, the tests are useful in the diagnosis of the autonomic neuropathies and distal small fiber neuropathy. The autonomic neuropathies (such as those due to diabetes or amyloidosis) are characterized by severe generalized autonomic failure. Distal small fiber neuropathy is characterized by an absence of autonomic failure except for distal sudomotor failure. Selective autonomic failure (which only one system is affected) can be diagnosed by autonomic testing. An example is chronic idiopathic anhidrosis, where only sudomotor function is affected. Among the synucleinopathies, autonomic function tests can distinguish Parkinson's disease (PD) from multiple system atrophy (MSA). There is a gradation of autonomic failure. PD is characterized by mild autonomic failure and a length-dependent pattern of sudomotor involvement. MSA and pure autonomic failure have severe generalized autonomic failure while DLB is intermediate.

Autonomic failure in primary amyloidosis.

Amyloidosis is an uncommon plasma cell dyscrasia affecting Multisystem, characterized by deposition of amyloid proteins in extracellular spaces and the tissues. Reported incidence of amyloidosis is 8 cases per million per year. Deposition of amyloid fibrils occurs in peripheral nerves in 20% of the cases in Primary Amyloidosis. Though. polyneuropathy is one of the presenting manifestations in cases of Primary Amyloidosis, pure autonomic failure without involving peripheral nerves is not a documented entity. Here, we present a case of Primary Amyloidosis presenting as Pure Autonomic Failure (Dysautonomia).