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Results for “Autonomic dysfunction”

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PubMed1991

Norepinephrine response in early HIV infection.

Norepinephrine response to a cold pressor test was investigated in 95 homosexual men in a longitudinal study of human immunodeficiency virus (HIV) infection. The baseline data obtained from 76 HIV+ and 19 HIV- subjects are included in this report. After the insertion of a venicatheter and following a 30 min rest, subjects immersed one of their hands in ice water for 2 min, and serial blood samples were obtained for the determination of catecholamine levels. The results show that the norepinephrine response in HIV+ subjects compared to that of HIV- subjects was blunted. Examination of the responses using linear and quadratic orthogonal polynomials suggested that these differences between the two groups were primarily a function of their rate of increase in norepinephrine levels. It was observed also that in HIV+ subjects, norepinephrine level peaked earlier than that in HIV- subjects. The data suggest that autonomic dysfunction is present in the early stages of HIV infection.

Autonomic Nervous System↗

PubMed1994

Diagnosis and treatment of Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome is a rare autoimmune neuromuscular and autonomic disease that produces fluctuating muscle weakness, hyporeflexia, and autonomic dysfunction, and often is associated with small-cell lung cancer. The pathophysiology is understood quite well; antibodies to voltage-gated calcium channels in motor and autonomic nerve terminals disrupt calcium influx and reduce acetylcholine release. The diagnosis may be suspected clinically, but must be confirmed with electrophysiologic testing. Initial and then periodic screening for malignancy is essential. Tumors other than small-cell lung cancer occasionally are found. Effective tumor treatment may induce remission. Active disease may respond to agents that enhance neuromuscular transmission or to immunosuppression. Combined therapy frequently is needed and control is often marginal despite this. It is expected that availability of 3,4-DAP will improve significantly the response to treatment in most patients.

Humans↗

PubMed1994

Lacrimation in Parkinson's disease.

The present study compares lacrimal secretion in control subjects and patients with Parkinson's disease with use of Schirmer's test. Tear secretion was decreased in Parkinson's disease. The reduction was more marked in stages III-IV than in stages I-II. The results are discussed in relationship with autonomic dysfunction in Parkinson's disease.

Aged↗

PubMed2000

Glucose tolerance and other determinants of cardiovascular autonomic function: the Hoorn Study.

AIMS/HYPOTHESIS: Currently, three categories of measures are used to assess cardiovascular autonomic dysfunction: measures of the Ewing-test, measures of heart-rate variability, and measures of baroreflex sensitivity. We studied the determinants of these measures obtained from cardiovascular autonomic function tests in the Hoorn Study. METHODS: The study group (n = 631) consisted of a glucose-tolerance-stratified sample from a 50- to 75-year-old group of people. Cardiac cycle duration (RR interval) and continuous finger arterial pressure were measured under three conditions: during (a) spontaneous breathing, (b) six deep breaths over one minute, and (c) an active change in position from lying to standing. From these readings, ten measures of autonomic function were assessed (three Ewing, six heart-rate variability and one baroreflex sensitivity). As possible determinants we considered age, sex, glucose tolerance, cardiovascular disease, use of anti-hypertensive drugs, anthropometric factors, metabolic factors and lifestyle factors. RESULTS: Multivariate analysis showed that eight of ten cardiovascular autonomic function measures were most strongly associated with glucose tolerance. Furthermore, measures were moderately associated with age, sex, waist-to-hip ratio, use of anti-hypertensive drugs, and insulin. The measures were weakly associated with coronary artery disease but not with lipids. The strongest determinants seemed to differ between subjects with and without diabetes: in the non-diabetic subjects the most strongly associated were age and use of anti-hypertensive drugs and in subjects with diabetes, insulin. No consistent differences in association between the three categories of measures were observed. CONCLUSION/INTERPRETATION: The strongest determinants of autonomic function were age, presence of diabetes and use of anti-hypertensive drugs.

Aged↗

PubMed2005

Effects of orthotopic liver transplantation on the corrected QT interval in patients with end-stage liver disease.

Autonomic dysfunction is a recognized complication of end-stage liver disease (ESLD) associated with a poor prognosis. The corrected QT interval (QTc) on electrocardiogram is a marker of autonomic function. A few small studies have suggested that QTc may normalize with the return of liver function after orthotopic liver transplantation. We sought to determine how transplantation affects the QTc in patients with ESLD. The QTc from the pretransplantation evaluation of 46 patients with ESLD was compared with the QTc at 4-month posttransplantation follow-up. Other factors that can influence autonomic function also were evaluated. Most patients with ESLD (54%) showed a prolonged QTc (> or = 440 msec) at the pretransplantation evaluation (451 +/- 45 msec) that improved to within the normal range at posttransplantation follow-up (418 +/- 18 msec; P < 0.001). There was no relationship between QTc prolongation and Child-Turcotte-Pugh score, Model for End-Stage Liver Disease score, diabetes mellitus, age, or etiology of liver disease. Most patients with ESLD and a prolonged QTc will have a significant improvement in QTc after transplantation; however, 6.5% of patients in our study had a worsening of QTc after transplantation.

Autonomic Nervous System↗

PubMed1985

Substance P given intrathecally at the spinal T9 level increases adrenal output of adrenaline and noradrenaline in the rat.

Administration of 10 micrograms of substance P intrathecally to the spinal T9 level of the adult rat, anaesthetized with urethane, provoked an increase in free catecholamines in plasma taken from the inferior vena cava. Adrenaline levels at 1 min after administration were 154.8 +/- 10.8% (mean +/- SE; n = 11) of preadministration levels and noradrenaline levels were 153.5 +/- 11.8% of preadministration levels. Differences between the values of free catecholamines in animals given substance P vs those given vehicle only were statistically significant at 1 and 10 min postinjection, but not at 30 min. Administration of a substance P analogue with central antagonistic properties 15 min before substance P was given prevented expression of the effects of substance P. These results suggest that substance P may be an excitatory chemical mediator of synaptic transmission in spinal pathways controlling adrenal medullary output. Thus dysfunction of substance P mechanisms may underlie some animal models of hypertension and may be involved in some cases of essential hypertension in man as well as in autonomic dysfunction associated with some neurological entities.

Adrenal Medulla↗

PubMed1981

[Changes in autonomic functions in diabetic neuropathy: cardiovascular reflexes and sweating].

Failure of autonomic functions in diabetes has been investigated. Cardiovascular reflexes, and thermoregulation during heat exposure, were studied in 11 diabetic patients. Five had clinical signs of sensorimotor neuropathy and 6 served as age- and sex-matched controls. The subjects were studied by the following tests: orthostatic test, Valsalva, beat-to-beat variation during normal and forced respiration, and analysis of urinary catecholamines. Thermoregulation was measured for 80 minutes, at an ambient temperature of 37 degrees C, in a gradient layer direct calorimeter measuring evaporative heat losses with a precision of +/- 1 watt. The cardiovascular tests showed a relationship between the sensorimotor defects and the autonomic dysfunctions. The beat-to-beat variation was found to be the most sensitive test, the Valsalva and orthostatic test being respectively less so. However, the diabetic patients' autonomic disorders were not associated with a significant decrease in evaporative heat losses. The internal temperature (esophageal) at which sweating began (set point) was higher in some of the neuropathic diabetics than in the controls. Once the set point had been reached, however, the increase in evaporative heat losses was greater in diabetics than in controls. These findings can be accounted for by zones of compensatory hypersweating in patients with polyneuropathy. The changes in evaporative heat loss pattern may represent an early alteration in autonomic diabetic neuropathy.

Adult↗

PubMed1998

[Anxiety and hemodynamics: correlations in hypertensive patients].

AIM: Syndrome analysis of functional relationships between personality disorders, autonomic regulation and psychic performance in relation to hemodynamic condition of hypertensive patients. MATERIALS AND METHODS: MMP1, Tailor's anxiety scale, Burdon and Schulte tables, variation pulsometry, tetrapolar chest rheography were used in examination of 86 patients with stage I and II hypertension. RESULTS: In early hypertension, weak anxiety and subclinical emotional disturbances, dominant was a parasympathetic trend of the vegetative tone without central control of the cardiac rhythm in hyperkinetic circulation. Changes in cortical neurodynamics manifested with minor attenuation of the ability to focus attention. Progression of angiospasticity and anxiety gave rise to psychic maladjustment in the form of anxiety-depression disorders with autonomic dysfunction in hypokinetic circulation, overcentralization of cardiac rhythm control. This was associated with a decline in mental performance. CONCLUSION: Systemic investigations of the emotional sphere, central hemodynamics and autonomic regulation of cardiac rhythm enable assessment of multilevel structure and severity of psychocardiac syndrome in hypertensive patients which is important both for therapeutic and expert practice.

Anxiety↗

PubMed2005

Head-down manoeuvre in patients with a high symptom score for orthostatic intolerance reveals impaired right brain frontal lobe vasoreactivity.

OBJECTIVE: Autonomic nerve dysregulation produces a sense of impaired well-being and interferes with work performance in affected individuals. In this study, we characterized the pathophysiology of this condition. METHODS: Six patients with high symptom scores for orthostatic intolerance (OI) along with age- and sex-matched normal volunteers were directed to perform a head-down manoeuvre, and the change in cerebral blood flow (CBF) and cerebral oxygen levels (rSO(2)) in the right and left frontal lobes was measured using near-infrared spectroscopy (NIRS). RESULTS: The head-down manoeuvre induced a much greater increase in right-sided total haemoglobin concentration (THbl) in normal volunteers (0.51+/-0.24) when compared to symptomatic patients (0.0+/-0.04) but had no effect on left-sided THbl (P<0.05) in either group. Five of 6 patients showed a gradual decrease in right-sided THbl when assuming a sitting position, and all patients with this pattern complained of symptoms of multiple autonomic dysfunction. Further, this pattern of changes in right-sided THbl was not observed in normal volunteers. CONCLUSIONS: The gradual decrease of THbl with the sitting position and the lack of increase during the head-down manoeuvre in symptomatic patients suggest that these patients have impaired vasoreactivity in the right frontal lobes. SIGNIFICANCE: This impaired vasoreactivity likely reflects dysfunction of the right hemisphere and the sympathetic nervous system in patients with OI.

Adult↗

PubMed1999

Platelet activation in diabetic cardiovascular autonomic neuropathy.

AIMS: Platelet activation is known to be associated with arrhythmic effects in myocardial ischaemia. The present study attempts to clarify whether diabetic cardiovascular autonomic neuropathy (CAN) is associated with intravascular platelet activation. METHODS: Platelet activation was assessed by flow cytometry analysis in 30 patients with Type 1 diabetes mellitus screened for diabetic complications. Fifteen patients showed evidence of CAN as assessed by a battery of standard cardiovascular autonomic reflex tests. Fifteen patients without CAN were then selected as a matched control group. Platelet activation was assessed by flow cytometric detection of activation-dependent platelet membrane antigens (P-selectin (CD62), thrombospondin, lysosomal GP53 (CD63) and ligand-induced binding site-1 of GPIIb/IIIa (LIBS-1)). RESULTS: Significantly more activated platelets were detected in the patients with CAN showing 20.9% (coefficient of variation (CV) 44%) CD63+ (vs. 17.2% (CV 19%) in controls, P < or = 0.05), 6.4% (CV 87%) CD62+ (vs. 4.1% (CV 37%), P < or = 0.05), and 6.7% (CV 55%) thrombospondin+ (vs. 4.6% (CV 39%), P < or = 0.01) platelets, respectively. LIBS-1 on platelets was not significantly different between patients with and without CAN. No correlation was found between glucose metabolism and platelet activation. CONCLUSIONS: Cardiovascular autonomic neuropathy is associated with platelet activation in Type 1 diabetes mellitus. The high platelet activation may reflect an increased prothrombotic state in diabetic cardiovascular autonomic dysfunction.

Adult↗

PubMed1994

Differences in autonomic nerve function in patients with silent and symptomatic myocardial ischaemia.

BACKGROUND: Autonomic neuropathy provides a mechanism for the absence of symptoms in silent myocardial ischaemia, but characterisation of the type of neuropathy is lacking. AIM: To characterise and compare autonomic nerve function in patients with silent and symptomatic myocardial ischaemia. METHODS AND RESULTS: The Valsalva manoeuvre, heart rate variation (HRV) in response to deep breathing and standing, lower body negative pressure, isometric handgrip, and the cold pressor test were performed by patients with silent (n = 25) and symptomatic (n = 25) ambulatory ischaemia and by controls (n = 21). No difference in parasympathetic efferent function between patients with silent and symptomatic ischaemia was recorded, but both had significantly less HRV in response to standing than the controls (p < 0.005 for silent and p < 0.01 for symptomatic). Patients with silent ischaemia showed an increased propensity for peripheral vasodilatation compared with symptomatic patients (p < 0.02) and controls (p < 0.04). Impaired sympathetic function was found in patients with pure silent ischaemia (n = 4) compared with the remaining patients with silent ischaemia whose pain pathways were presumed to be intact. CONCLUSIONS: Patients with silent ischaemia and pain pathways presumed to be intact have an enhanced peripheral vasodilator response, and if this applied to the coronary vasculature it could provide a mechanism for limiting ischaemia to below the pain threshold. Patients with pure silent ischaemia have evidence of sympathetic autonomic dysfunction.

Autonomic Nervous System↗

PubMed1992

[Autonomic nerve preserving operation for rectal carcinoma: preliminary postoperative urinary function of 15 cases].

The autonomic nerve preserving operation was performed on 15 patients with rectal carcinoma (9 men and 6 women), from August 1990 to February 1991. The average age was 57.2 years ranging from 28 to 70 years. Low anterior resection was performed on 6 patients having middle rectal carcinoma. Seven Colonic anastomosis and two abdominoperineal resections were performed for lower rectal carcinoma. The average operation time was 4 hours and 22 minutes. The average blood loss was 1560 cc. Urinary functions were evaluated pre- and post-operatively. None of the patients needed re-catheterization postoperatively. Urodynamic studies showed no significant differences. We recommend this operation for rectal cancer because it prevented the postoperative autonomic dysfunction without affecting the curability.

Adult↗

PubMed1979

Hemodialysis hypotension is not the result of uremic peripheral autonomic neuropathy.

Five chronic hemodialysis patients with persistent hypotension during dialysis (MAP: 74.2 +/- 3.1 mm Hg) were given a number of standard tests of autonomic nervous system function and compared with eight normotensive hemodialysis patients (MAP: 96.4 +/- 3.4 mm Hg). Tests of efferent sympathetic nerves were normal in both groups, as were plasma catecholamine levels and the cold pressor test. The response to Valsalva maneuver and the venoconstriction reflex were generally abnormal and did not differentiate between the two groups. When adjusted for age and MAP, the baroreceptor slope to a high-pressure stimulus was diminished only in the hypotensive subjects. This result reinforces the previously described finding that many uremic patients do not develop a normal cardioacceleration during hypotension. Although reduced baroreceptor sensitivity may be a factor in the chronic hypotension of some hemodialysis patients, autonomic dysfunction alone is not a sufficient explanation of this phenomenon.

Adult↗

PubMed2003

Headaches with (ipsilateral) autonomic symptoms.

Primary short-lasting headaches broadly divide themselves into those associated with autonomic symptoms, so called trigemino-autonomic cephalgias (TACs), and those with little autonomic syndromes. The trigeminoautonomic cephalgias include cluster headache and paroxysmal hemicranias, in which head pain and cranial autonomic symptoms are prominent. The most striking feature of cluster headache is the circadian and circannual periodicity of the attacks. Inheritance may play a role in some families. The attacks are of extreme intensity, of short duration, occur unilaterally, and are accompanied by symptoms of autonomic dysfunction. Medical treatment includes both acute therapy aimed at aborting individual attacks and prophylactic therapy aimed at preventing recurrent attacks during the cluster period. Some types of trigemino-autonomic headaches, such as paroxysmal hemicrania and hemicrania continua have, unlike cluster headaches, a very robust response to indomethacin, leading to a consideration of indomethacin-sensitive headaches.

Autonomic Nervous System↗

PubMed1999

Orthostatic intolerance. A historical introduction to the pathophysiological mechanisms.

Several of the pathophysiological mechanisms resulting in orthostatic intolerance (ie, tachycardia) have been recognized individually over the course of the past 100 years or more. More recent definitions of the normal ranges of orthostatic blood pressure and heart rate changes have facilitated the recognition of pathogenetic disorders that are probably shared in various proportions between orthostatic intolerance and various types of orthostatic hypotension. These include autonomic dysfunction of (1) the leg veins almost invariably causing excessive gravitational blood pooling, usually associated with (2) hypovolemia of circulating erythrocytes and plasma that is probably attributable to impaired autonomic stimulation of erythropoietin production, renin release, and (less consistently) aldosterone secretion. Improved understanding of these apparent results of lower body dysautonomia should facilitate more effective therapy in the future.

History, 19th Century↗

PubMed1994

Reliability and validity of cardiovascular and vasomotor autonomic function tests.

OBJECTIVE: To determine the reliability and validity of autonomic function tests (AFTs) as clinical tools for diagnosing diabetic autonomic dysfunction. RESEARCH DESIGN AND METHODS: Twenty-one healthy control subjects and 21 insulin-dependent diabetes mellitus (IDDM) patients (11 with no symptomatology and 10 with symptomatic diabetic autonomic neuropathy [DAN]) were matched for age, and administered three standard cardiovascular tests and two new vasomotor tests of autonomic function. Each of the cardiovascular tests (change in heart rate [delta bpm], Valsalva ratio [VR], change in systolic blood pressure [delta sBP]) and vasomotor tests (total pulse amplitude [TPA] and percent vasoconstriction [%VC]) were repeated within 1 week. Infrared photoplethysmography measured sympathetic-mediated vasomotor function. Reliability was determined by intraclass correlation coefficients. Validity was determined by analysis of variance procedures to test for differences between known groups and by computing sensitivity, specificity, and positive and negative predictive values. RESULTS: All AFTs were reliable, with %VC having highest reproducibility (r = 0.90). AFT scores were not different from time 1 to time 2. After controlling for age, two cardiovascular tests had significantly different values for control subjects and asymptomatic diabetic patients. AFTs, except delta sBP, were significantly different between symptomatic diabetic patients and asymptomatic diabetic patients after controlling for age and duration of disease simultaneously. Sensitivity, specificity, and predictive values for %VC were comparable to the values for delta bpm and VR. TPA indexes were lower but clinically acceptable. CONCLUSIONS: AFTs were found to be reliable and valid tests for detecting DAN. TPA and %VC are important because they measure an aspect of sympathetic function not assessed by standard cardiovascular AFTs, and they do not depend on the patient's cooperation or ability to exert effort.

Adult↗

PubMed1998

Autonomic assessment of cardiovascular disease.

Autonomic dysfunction plays a major role in the pathophysiology of many medical conditions, particularly cardiovascular disorders and diabetes mellitus. This article describes some of the methods used to assess cardiovascular autonomic function, and concentrates on the techniques that have a current or potential clinical application.

Autonomic Nervous System↗

PubMed1994

Time-frequency analysis of slow cortical activity and cardiovascular fluctuations in a case of Alzheimer's disease.

The dynamics and relationship of slow cortical activity (amplitude modulation of electroencephalograph at 0.02-0.05 Hz) and cardiovascular fluctuations (0.01-0.05 Hz range) was studied by time-frequency mapping (modified Wigner distribution) in a patient with Alzheimer's disease. The amplitude modulating at rest basal alpha and theta activity (lead Oz) was exaggerated compared with control subjects. Fluctuations at respiratory and nonrespiratory (0.01-0.05 Hz) frequencies in R-R intervals and blood pressure were present and within normal range. Spontaneous hypotension (by 20 to 80 mmHg lasting 15-20 s) accompanied by cardioacceleration occurred repeatedly in the supine position and during hyperventilation. Slow cortical activity and nonrespiratory fluctuations (0.01-0.05 Hz) in blood pressure increased concurrently with hypotensions. No signs of peripheral autonomic dysfunction or malfunction of baroreceptors were observed and the vasomotor instability appeared to be of central origin. The results suggested that slow cortical activity was functionally related to the central autonomic nervous system and reflected cortico-thalamo-brainstem interaction.

Alpha Rhythm↗