Evaluación clínica de las disautonomías / Clinical evaluation of dysautonomia

INTRODUCCIÓN: Disfunción del sistema nervioso autonómico ocurre en enfermedades del sistema nervioso central y periférico. Es importante cuantificar el compromiso simpático y parasimpático, diagnosticar la disfunción, monitorizar la evolución y la respuesta a terapias. Las principales pruebas funcionales son las cardiovasculares y sudomotoras. Existen además exámenes para estudiar la disfunción autonómica en distintos órganos y que son específicos de las especialidades médicas respectivas. DESARROLLO: Se describen los síntomas, las pruebas funcionales y métodos de estudio a nivel cardiovascular: simpáticas vasomotoras (noradrenérgicas) y cardiovagales (colinérgicas) y las pruebas para la sudoración: sudomotoras simpáticas (colinérgicas). Se describen los síntomas y exámenes a nivel pupilar, urogenital y gastrointestinal. Se señala la utilidad de las pruebas funcionales autonómicas en el estudio de distintas patologías neurológicas. CONCLUSIONES: la evaluación conjunta de los hallazgos clínicos y de las pruebas funcionales autonómicas permiten determinar el nivel anatómico y el grado de severidad de la disfunción autonómica con un fundamento fisiopatológico.

INTRODUCTION: Autonomic dysfunction occurs in patients with central and peripheral nervous system diseases. It is important to quantify the sympathetic and parasympathetic involvement for the diagnosis of the autonomic failure, for follow up and evaluate the response to a specific treatment. The most important studies are cardiovascular and sudomotor functional tests. There are other tests for the study of autonomic dysfunction in different organs, that are specific to respectively medical specialty. DEVELOPMENT: we describe main symptoms, functional autonomic tests and other methods to study cardiovascular: sympathetic vasomotor (noradrenergic) and cardiovagal (cholinergic) and sudomotor: sympathetic (cholinergic) functions. We describe symptoms and tests for assessment pupillary, genitourinary and gastrointestinal autonomic dysfunction. The indications for autonomic function testing in the different clinical scenarios are reported. CONCLUSIONS: combined evaluation of clinical and tests of autonomic function results allow to obtain the level and severity of autonomic dysfunction based upon pathophysiological support.

Evaluation of cardiac autonomic modulation using symbolic dynamics after cardiac transplantation

Abstract Objective: To characterize the behavior of cardiac autonomic modulation in individuals with different times after orthotopic heart transplantation (HTx) using symbolic dynamics analysis. Methods: Sixty patients were evaluated after HTx. We recorded their instantaneous R-R intervals (RRi) by cardiac monitor Polar® RS800CX™ (Polar Electro Oy, Kempele, Finland) for 10 minutes. The same sequence of RRi with 256 consecutive beats was used to perform spectral analysis and symbolic dynamics analysis. We used hierarchical clustering to form groups. One-way analysis of variance (ANOVA) (with Holm-Sidak method) or one-way Kruskal-Wallis test (with Dunn´s post-hoc test) was used to analyze the difference between groups. Linear correlation analysis between variables was performed using Pearson's or Spearman's tests. P-value < 0.05 was considered statistically significant. Results: The 0V% index increased, the 2UV% index and the normalized complexity index decreased with an increase of HTx postoperative time. There were a negative correlation between complexity indexes and 0V% and a positive correlation between complexity indexes and 2UV%. Conclusion: Symbolic dynamics indexes were able to show a specific cardiac autonomic modulation pattern for HTx recipients with different postoperative times.

Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients / Anticorpos muscarínicos e resposta da frequência cardíaca ao exercício dinâmico e a manobra de Valsalva na doença de Chagas crônica

We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.

Foram estudadas as respostas cronotrópicas cardíacas à manobra de Valsalva e ao exercício dinâmico de vinte pacientes chagásicos com função ventricular esquerda normal e sem alterações da contractilidade segmentar por ecocardiografia bidimensional. O aumento absoluto da frequência cardíaca dos pacientes (Δ = 21,5 ± 10 bpm, M ± DP) durante a manobra de Valsalva foi significativamente menor quando se comparava ao grupo controle (Δ = 31,30 ± 70, p = 0,03). A frequência cardíaca mínima (58,24 ± 8,90 vs 62,80 ± 10, p = 0,68) e a diminuição da frequência cardíaca absoluta no final da manobra (Δ = 38,30 ± 13 vs Δ = 31,47 ± 17, p = 0,10) não foram diferentes em comparação com o grupo controle. A aceleração inicial da frequência cardíaca durante o exercício dinâmico (Δ = 12 ± 7,55 vs Δ = 19 ± 7,27, p = 0,01) também foi menor, mas a recuperação da frequência cardíaca, durante os primeiros dez segundos, foi maior no grupo sero-positivos [mediana:14 (intervalo interquartil: 9,75-17,50) vs 5 (0 - 8,75), p = 0,001]. Os níveis séricos de auto-anticorpos muscarínicos cardíacos foram significativamente maiores nos pacientes chagásicos do que no grupo controle [(mediana: 34,58 densidade óptica (intervalo interquartil 17 - 46,5) vs (mediana: 0, intervalo interquartil 0 - 22,25) p = 0,001] e a correlação é significativa e direta (r = 0,68, p = 0,002) com o início da recuperação da frequência cardíaca durante o exercício dinâmico. Os resultados desta investigação sugerem que indiretamente, os auto-anticorpos muscarínicos cardíacos, podem ter ação agonista positiva sobre o controle parassimpático da frequência cardíaca dos pacientes chagásicos.

Parasympathetic dysfunction is associated with insulin resistance in fructose-fed female rats

The objective of the present study was to identify metabolic, cardiovascular and autonomic changes induced by fructose overload administered in the drinking water of rats for 8 weeks. Female Wistar rats (200-220 g) were divided into 2 groups: control (N = 8) and fructose-fed rats (N = 5; 100 mg/L fructose in drinking water for 8 weeks). The autonomic control of heart rate was evaluated by pharmacological blockade using atropine (3 mg/kg) and propranolol (4 mg/kg). The animals were submitted to an intravenous insulin tolerance test (ITT) and to blood glucose measurement. The fructose overload induced a significant increase in body weight (~10 percent) and in fasting glycemia (~28 percent). The rate constant of glucose disappearance (KITT) during ITT was lower in fructose-fed rats (3.25 ± 0.7 percent/min) compared with controls (4.95 ± 0.3 percent/min, P < 0.05) indicating insulin resistance. The fructose-fed group presented increased arterial pressure compared to controls (122 ± 3 vs 108 ± 1 mmHg, P < 0.05) and a reduction in vagal tonus (31 ± 9 vs 55 ± 5 bpm in controls, P < 0.05). No changes in sympathetic tonus were observed. A positive correlation, tested by the Pearson correlation, was demonstrable between cardiac vagal tonus and KITT (r = 0.8, P = 0.02). These data provided new information regarding the role of parasympathetic dysfunction associated with insulin resistance in the development of early metabolic and cardiovascular alterations induced by a high fructose diet.

Avaliação da função autonômica na cardiomiopatia hipertrófica / Assessing autonomic function in hypertrophic cardiomyopathy

OBJETIVO: Avaliar a função autonômica na cardiomiopatia hipertrófica (CMH) através da variabilidade da freqüência cardíaca (VFC) e correlacioná-la com dados ecocardiográficos. MÉTODOS: Foram estudados 2 grupos pareados por sexo, idade e freqüência cardíaca: A) 10 pacientes com CMH septal (70 por cento não obstrutiva); B) 10 voluntários saudáveis. A VFC foi analisada durante quatro estágios sucessivos: repouso, respiração controlada, teste de inclinação e respiração controlada associada ao teste de inclinação. Compararam-se as médias das variáveis entre os grupos, intragrupos durante os estágios, e no grupo A, correlacionando com as medidas ecocardiográficas (septo interventricular e diâmetro atrial esquerdo). RESULTADOS: Não observamos diferença na VFC entre os grupos nos 3 primeiros estágios. No 4° estágio, constatamos que medidas de atividade vagal apresentaram valores maiores no grupo A [logaritmo da raiz média quadrática das diferenças entre intervalos RR (LogRMSSD) - 1,35±0,14 vs 1,17±0,16; p=0,019; logaritmo do componente alta freqüência (LogAF)-4,89±0,22 vs 4,62±0,26; p=0,032]. Durante os estágios, também verificamos que medidas vagais [proporção de pares de intervalos RR consecutivos cuja diferença > 50ms (pNN50) e LogAF] apresentaram menor redução durante o 3° estágio no grupo A, e o LogAF, um aumento no último estágio (p=0,027), indicando marcante atividade parassimpática neste grupo. A análise da VFC do grupo A não revelou diferença entre pacientes com maior hipertrofia ou diâmetro atrial. CONCLUSÃO: 1) ocorreu predomínio parassimpático durante estimulação autonômica nos pacientes com CMH; 2) não encontramos correlação entre VFC e as medidas ecocardiográficas analisadas.

Intervención colinérgica en la enfermedad de Alzheimer y otras manifestaciones neuropsiquiátricas / Cholinergic intervention in Alzheimerïs disease and other neuropsychiatric manifestations

Las neuronas colinérgicas del telencéfalo basal suministran una profusa inervación a toda la corteza cerebral, constituyendose en el principal sistema modulador de la actividad cortical, participando en la regulación del estado de alerta y la atención. La denervación colinérgica, secundaria a la degeneración de estas neuronas en la enfermedad de Alzheimer, se relaciona directamente con el desarrollo de los síntomas de enfermedad, lo que ha impulsado la búsqueda de diversas formas de suplir la deficiencia de acetilcolina en la corteza. Hasta ahora los inhibidores de la acetilcolinesterasa han entregado los mejores resultados, pero estos no han sido más que modestos. En la presente revisión se examinan las bases fisiológicas y fisiopatológicas que avalan la intervención sobre el sistema colinérgico central y se examinan los resultados registrados en la enfermedad de Alzheimer y su extensión hacia otras manifestaciones neurosiquiátricas. Finalmente, se hace enfásis en que tratandose de una enfermedad degenerativa, lo más trascendente no es la disminución de un neurotransmisor, sino la perdida de las neuronas que los secretan y la interrupción de los circuitos en que estas neuronas participan

Autonomic nervous system reactivity in irritable bowel syndrome.

BACKGROUND: Autonomic dysfunction has been implicated as one of the factors involved in the pathogenesis of irritable bowel syndrome (IBS). AIM: To evaluate autonomic function in patients with IBS. METHODS: Thirty-five patients with IBS and thirty healthy controls were evaluated by standard cardiovascular reflex tests. Parasympathetic function was assessed by measuring heart rate responses to deep and slow breathing (E:I ratio), Valsalva maneuver (Valsalva ratio) and head-up tilt tests (30:15 ratio). Sympathetic adrenergic function was assessed by measuring diastolic blood pressure responses to handgrip test at 4 min and cold pressor test at 1 min and also by change in systolic blood pressure in response to head-up tilt. Autonomic functions were tested twice, keeping at least a one-week interval, to find out stability over time. Anxiety status of the subjects was assessed by evaluating responses to a questionnaire. RESULTS: Parasympathetic reactivity was significantly increased in IBS patients as compared to controls during visit 1 (E:I 1.7 [SD 0.2] vs 1.4 [0.1], p < 0.001; Valsalva ratio 2.0 [0.3] vs 1.5 [0.1], p < 0.001; 30:15 ratio 1.2 [0.1] vs 1.1 [0.01], p < 0.001). Similar results were obtained in visit 2. The diastolic blood pressure responses during handgrip and cold pressor tests were not different in comparison to controls during both the visits. However, tilting resulted in less marked rise in diastolic blood pressure (9.1 [4.1] vs 12.1 [6.8] mmHg, p < 0.01) at 0.5 min and less rise in heart rate (6.0 [2.5] vs 10.3 [6.3] per min, p < 0.01) at 1 min in IBS patients during visit 1. The anxiety score of IBS patients was significantly higher (46.2 [3.2] vs 21.6 [1.7], p < 0.001). CONCLUSION: IBS patients have increased parasympathetic reactivity and a high level of anxiety trait.

Miocardiopatía chagásica y sistema nervioso autónomo. Estudios Clínicos / Clinical studies of the autonomic nervous system in chagasic myocardiopathy

El sistema nervioso autónomo de los pacientes con enfermedad de Chagas avanzada es anormal. La gran mayoría de los investigadores considera que estas anormalidades son primarias, específicas e irreversibles. Sin embarrgo ¿cuando y por que aparecen estas anormalidades, en la historia natural de la enfermedad?, sigue siendo objeto de intensa controversia. Estudios morfológicos y funcionales recientes indican claramente que las anormalidades simpáticas y parasimpáticas, están precedidas por el daño miocárdico y la disfunción ventricular izquierda. En consecuencia, las alteraciones parasimpáticas cardiacas y la activación neurohormonal de los pacientes con enfermedad de Chagas son muy probablemente secundarias y reversibles. Es imperativo realizar investigaciones adicionales neurohormonal contribuye a la progresión del daño miocárdico y de la disfunción ventricular

Trypanosoma cruzi strains and autonomic nervous system pathology in experimental Chagas disease

Lesions involving the sympathetic (para-vertebral ganglia) and para-sympathetic ganglia of intestins (Auerbach plexus) and heart (right atrial ganglia) were comparatively analyzed in mice infected with either of three different strain types of Trypanosoma cruzi, during acute and chronic infection, in an attempt to understand the influence of parasite strain in causing autonomic nervous system pathology. Ganglionar involvement with neuronal destruction appeared to inflammation, which most of the times extended from neighboring adipose and cardiac, smooth and striated muscular tissues. Intraganglionic parasitism was exceptional. Inflammation involving peripheral nervous tissue exhibited a focal character and its variability in the several groups examined appeared unpredictable. Althought lesions were generally more severe with the Y strain, comparative qualitative study did not allow the conclusion, under the present experimental conditions, that one strain was more pathogenic to the autonomic nervous system than others. No special tropism of the parasites from any strain toward autonomic ganglia was disclosed.

Central noradrenergic and cholinergic modulation of formaldehyde-induced pedal inflammation and nociception in rats.

Possible central noradrenergic and cholinergic modulation of acute peripheral inflammation was investigated in rats, adopting the formaldehyde-induced pedal inflammation as the experimental model. Intracerebroventricularly (icv) administered noradrenaline (NA), alpha-adrenoceptor agonist, L-phenylephrine, alpha-2 adrenoceptor agonist, clonidine and non-selective beta-adrenoceptor blocker, propranolol, suppressed formaldehyde-induced inflammation producing a decrease in oedema volume and increase in pain threshold. Conversely, both noradrenergic neuron degenerator, 6-hydroxydopamine (6-OHDA) and non-selective alpha-adrenoceptor antagonist, phenoxybenzamine produced an increase in paw oedema along with an augmentation of pain. Significant oedema augmenting effects were also produced by central excitatory neurotransmitter, acetylcholine (ACh) on icv administration. ACh also produced pro-nociceptive action. An ACh antagonist, scopolamine and ACh synthesis inhibitor, hemicholinium-3 (HC) reduced pedal oedema and produced analgesia. The results of this study indicate that central NA exerts an inhibitory effect on peripheral oedema and pain whereas, ACh has an augmenting effect on formaldehyde-induced peripheral inflammation.

Neuronal counting and parasympathetic dysfunction in the hearts of chronically Trypanosoma cruzi infected rats

Dez ratos machos Wistar cronicamente infectados pelas cepas Colombiana, Sao Felipe (12SF), e Y do Trypanosoma cruzi, foram submetidos, apos 8 meses de infeccao, juntamente com dez animais controles, ao teste da resposta bradicardica barorreflexa pela injecao endovenosa de fenilefrina. Seis ratos chagasicos exibiram disfuncao cardiaca parassimpatica, caracterizada pela depressao do indice da resposta bradicardica barorreflexa. Embora o estudo histologico dos coracoes chagasicos mostrasse lesoes dos ganglios atriais, a contagem dos neuronios em cortes seriados, nao apresentou reducao numerica significativa dos mesmos.

Changes in choline acetyltransferase activity of rat tissues during Chagas' disease

1. The activity of choline acetyltransferase (CAT) measured by a radilabeling method was significantly reduced in the heart, submandibular gland and esophagus of rats 20 days after inoculation with Trypanosoma cruzi (Y strain). 2. Normal enzyme activity was recovered in all these organs 100 days after inoculation. 3. In the transcerse colon, no change, 30% reduction and normal activity were found at days 20, 100 and 430 of infection, respectively. 4. The data indicate recovery of parasympathetic function in experimental Chagas' disease. Axonal regrowth and sprouting are discussed as possible candidates for the recovery mechanisms