SEARCH · PubMed Health

Results for “Autonomic dysfunction”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources

PubMed1977

Pheochromocytoma and autonomic dysfunction.

Patients with hypertension due to the release of large amounts of NE from a pheochromocytoma and patients with PAD and postural hypotension due to diminished NE release from adrenergic axon terminals represent the extremes of the spectrum of adrenergic pathophysiolgic findings. It is reasonable to suspect that some more common disorders lie between these extremes and to anticipate that potential roles of the adrenergic nervous system in the pathogenesis of these disorders will be extensively studied with the availability of sensitive isotope-derivative methods for the measurement of catecholamine levels in plasma and in tissue.

Adolescent↗

PubMed1995

[Autonomic dysfunction and the development of secondary brain death syndrome].

Vegetative disturbances were observed in 88 out of 102 patients, 86%, after a primary brain lesion during onset of brain death. Tachycardia was most common in 64%, hypotonia below 80 mm Hg and hypertonia above 170 mm Hg were present in about half of all cases. Hyperthermia above 40 degrees C was noted in 25%, hypothermia below 36 degrees C was observed in 31%. The kind of underlying brain lesion had no regular influence on the vegetative disturbances. In 5 out of 6 younger patients these disturbances were less pronounced.

Adolescent↗

PubMed2000

Autonomic dysfunction in patients with fibromyalgia: application of power spectral analysis of heart rate variability.

OBJECTIVES: To assess the interaction between the sympathetic and parasympathetic systems in patients with fibromyalgia syndrome (FM), using power spectrum analysis (PSA) of heart rate variability (HRV). In addition, we explored the association between HRV, measures of tenderness, FM symptoms, physical function, psychological well being and quality of life. METHODS: We studied 22 women with FM and 22 age-matched healthy women. Twenty-minute electrocardiogram recordings were obtained in a supine position during complete rest. Spectral analysis of R-R intervals was done by the fast-Fourier transform algorithm. RESULTS: Heart rate was significantly higher in FM patients compared with controls (P < .006). FM patients had significantly lower HRV compared with controls (P= .001), and higher low-frequency (LF) and lower high-frequency (HF) components of PSA than controls (P < .001). Quality of life, physical function, anxiety, depression, and perceived stress were moderately to highly correlated with LF, HF (in normalized units), and LF/HF. No association was observed between HRV parameters and measures of tenderness and FM symptoms. CONCLUSIONS: The basal autonomic state of patients with FM is characterized by increased sympathetic and decreased parasympathetic tones. Autonomic dysregulation may have implications regarding the symptomatology, physical and psychological aspects of health status.

Algorithms↗

PubMed2002

Predisposition to arrhythmia and autonomic dysfunction in Nhlh1-deficient mice.

Nhlh1 is a basic helix-loop-helix transcription factor whose expression is restricted to the nervous system and which may play a role in neuronal differentiation. To directly study Nhlh1 function, we generated null mice. Homozygous mutant mice were predisposed to premature, adult-onset, unexpected death. Electrocardiograms revealed decreased total heart rate variability, stress-induced arrhythmia, and impaired baroreceptor sensitivity. This predisposition to arrhythmia is a likely cause of the observed death in the mutant mice. Heterozygosity for the closely related transcription factor Nhlh2 increased the severity of the Nhlh1-null phenotype. No signs of primary cardiac structural or conduction abnormalities could be detected upon necropsy of the null mice. The pattern of altered heart rhythm observed in basal and experimental conditions (stress and pharmacologically induced) suggests that a deficient parasympathetic tone may contribute to the arrhythmia in the Nhlh1-null mouse. The expression of Nhlh1 in the developing brain stem and in the vagal nuclei in the wild-type mouse further supports this hypothesis. The Nhlh1 mutant mouse may thus provide a model to investigate the contribution of the autonomic nervous system to arrhythmogenesis.

Animals↗

PubMed1987

Measurement of blood pressure and heart-rate variation while resting supine and standing for the evaluation of autonomic dysfunction.

Blood pressure and R-R interval variation were studied during postural changes using a tilting table. The subjects were 64 normal controls and 52 patients with various disorders. None of the normal controls showed postural falls of more than 15 mm Hg in mean blood pressure. The mean loge coefficient of variation of 100 R-R intervals was significantly reduced in groups with Parkinson's disease, spinocerebellar degeneration, Shy-Drager syndrome and diabetes mellitus, compared with a normal control group. Reduced heart-rate variation was frequently associated with sphincter disturbance and orthostatic hypotension.

Adolescent↗

PubMed1991

Sympathetic autonomic dysfunction. Programmed subcutaneous noradrenaline administration via microdosing pump.

Sympathetic dysfunction is characterized by postural hypotension, decreasing blood pressure without compensatory tachycardia during graded supine ergometric exercise, impaired catecholamine metabolism, and hypersensitivity to catecholamines. We report on eight patients, seven with sympathetic dysfunction, of whom three patients were treated for the first time with programmed subcutaneous noradrenaline administration by means of a microdosing pump over a time period of 1.5-13 months. A clear improvement in blood pressure values, orthostasis tolerance, and exercise capacity has been observed in these three patients which permit them to extend their action radius. Adjustment of the noradrenaline dose to the wide range of everyday stress and the possible occurrence of adrenoreceptor desensitization, however, remains a severe problem.

Adult↗

PubMed2000

Skin and muscle vasomotor reflexes in detecting autonomic dysfunction in leprosy.

There are few tests to assess the function of small unmyelinated nerve fibers. One established test is the skin vasomotor reflex (SVMR), which uses laser doppler flow velocimetry. The SVMR has the disadvantages of being susceptible to interference (from change of temperature and alerting stimuli) and of requiring expensive equipment. An ultrasound doppler method, which is less expensive, can be used to detect muscle vasomotor reflex (MVMR) activity. We sought to compare the efficacy of these two methods in detecting dysfunction of small unmyelinated nerve fibers in patients with leprosy. SVMR was shown to be less sensitive (P < 0.01) and specific (P < 0.001) than MVMR. The favorable results of MVMR may be attributed to its lesser susceptibility to interfering sympathetic vasoconstriction from alerting stimuli. MVMR also reflects larger areas of blood vessel innervation than the laser doppler method. In leprosy, nerve damage is typically patchy and may be missed by the smaller sampling of the laser method.

Adolescent↗

PubMed1999

Haemodynamic response to an isometric exercise test in obese patients: influence of autonomic dysfunction.

OBJECTIVE: To investigate blood pressure (BP) and heart rate (HR) responses to an isometric exercise test in obese non diabetic patients and to correlate the results with vagal function and plasma insulin concentration. SUBJECTS: 63 obese patients, 36 of whom had abnormal cardiac parasympathetic control (PS+), and 35 healthy control subjects. METHODS: Analysis of HR variations during three standardized tests: deep-breathing, lying-to-standing and Valsalva. Isometric contraction (handgrip) for 5 min. RESULTS: In the PS+ obese patients, resting HR and body mass index (BMI) were significantly higher than in the PS- subjects and there was a trend to higher plasma insulin concentrations. Age-matched comparison showed that during the handgrip test, the increase in HR at the first minute was significantly higher in the PS- obese patients than in the controls. The increase in BP was significantly lower in the PS+ obese patients than in age-and-BMI-matched PS- obese patients. CONCLUSION: These data suggest that 1) there is an increase in cardiac vagal tone in PS- obese patients, since the early increase in HR at 1 min of the handgrip test, results from the withdrawal of vagal tone; 2) BP response to an isometric contraction is impaired in PS+ obese patients due to a lower sympathetic activation; 3) high plasma insulin concentrations may also contribute to limiting the BP response; and 4) autonomic disorders may account for alterations in the haemodynamic changes during exercise.

Adolescent↗

PubMed1996

Abnormal heart rate variability as a manifestation of autonomic dysfunction in hemispheric brain infarction.

BACKGROUND AND PURPOSE: Abnormal heart rate variability is related to prognostically unfavorable ventricular arrhythmias and sudden arrhythmic death in coronary artery disease. Short-term electrocardiographic (ECG) recordings have shown similar abnormalities of heart rate variability in patients with acute stroke. However, there is no information regarding the clinical significance of these abnormalities and of heart rate variability in long-term ECG recordings in stroke. METHODS: In this prospective study, we analyzed the time domain and frequency domain measures of heart rate variability from 24-hour ECG recordings in 31 consecutive patients with hemispheric brain infarction in the acute phase and at 1 and 6 months after the infarction and in 31 age- and sex-matched healthy control subjects. RESULTS: All the measured components of heart rate variability, ie, standard deviation of RR intervals (P < .001), total power (P < .0001), very-low-frequency power (P < .0001), low-frequency power (P < .001), and high-frequency power (P < .05), were significantly lower than those of the control subjects in both the acute phase and 1 and 6 months later. Impaired heart rate variability correlated with the severity of neurological deficits and disability. In five patients with increased intracranial pressure due to large brain infarction, no relevant spectral components were found. CONCLUSIONS: Hemispheric brain infarction seems to cause significant long-lasting damage to the cardiovascular autonomic regulatory system manifested as abnormalities of heart rate variability. Distorted heart rate variability in the acute phase of stroke may be prognostically unfavorable.

Acute Disease↗

PubMed1989

A new measuring design for autonomic dysfunction of skin in neuropathies: hyperthermal laser-Doppler flowmetry.

Twenty patients suffering from diabetic neuropathy, 20 patients suffering from alcoholic neuropathy and 20 healthy volunteers within the same age range were studied for the stimulability of microcirculation with a new measuring design. A laser method (laser-Doppler flowmetry) was used to evaluate the increase of the microvascular blood flow of the skin during the hyperthermal phase. It evaluated the degree of increase of microcirculatory blood flow as well as the time from the beginning of hyperthermy to the onset of change in perfusion (the hyperthermal perfusion latency). This was significantly prolonged in both neuropathy groups; the increase of the microvascular blood flow in the diabetic neuropathies was significantly lower than found in alcoholic neuropathies and in healthy volunteers.

Aged↗

PubMed1992

Asymmetrical autonomic dysfunction of the feet after retroperitoneal surgery in patients with testicular cancer: 2 case reports.

We report on 2 patients with hyperhidrosis and decreased temperature of the leg on the unoperated side after unilateral retroperitoneal lymph node dissection. Both patients had a 4 to 5C difference in skin temperature of the feet, with the operated side being warm and dry compared to the nonoperated side. This condition is most likely due to a lesion of sympathetic fibers or ganglia located in close proximity to the retroperitoneal lymph nodes, resembling a unilateral lumbar sympathectomy. In addition, both patients had profuse sweating and a subjective feeling of coldness of the leg on the nonoperated side, which caused considerable discomfort. This latter phenomenon most likely represents a compensatory sympathetic hyperfunction due to the decreased sympathetic function in the other leg.

Adult↗

PubMed1997

Autonomic dysfunction in Parkinson's disease assessed by sympathetic skin response: a prospective clinical and neurophysiological trial on 50 patients.

To verify possible dysfunction of sympathetic skin activity in Parkinson's disease (PD), we studied the electrically evoked sympathetic skin responses (SSR) bilaterally at hands and feet in a group of 50 PD patients and in normal subjects. SSR was present in all patients. Nevertheless, significant differences in the latency and amplitude values were noted. In the group of patients prolongation of latency as well as the reduction of SSR amplitude correlates with age. The longer the disease the more SSR abnormalities could be found. Gender, type of clinical manifestation of PD or medication had no statistically significant effects. However, motor symptom asymmetries evaluated separately for each body side correlated well with interside asymmetries of SSR.

Aged↗

PubMed1989

Use of laser Doppler flowmetry and transcutaneous oxygen tension electrodes to assess local autonomic dysfunction in patients with frozen shoulder.

The laser Doppler flowmeter (LDF), which measures changes in cutaneous blood flow, and the transcutaneous oxygen electrode which measures cutaneous perfusion, were used to study reflex changes in the microcirculation of the shoulder in 38 patients with frozen shoulder and 10 normal controls. In all controls and 22 patients with frozen shoulder, a normal LDF response to inspiration/expiration was observed. In 16 patients with frozen shoulder, LDF responses were either unilaterally or bilaterally absent. Comparison between the two patient groups showed a significant association (chi 2 = 6.43, P less than 0.02) between abnormality of response and the persistence of pain. TcPO2 was in the normal range in all patients and controls. These findings suggest that the LDF together with the TcPO2 may be a useful method of studying the skin microcirculation over the shoulder.

Adult↗

PubMed2005

Autonomic dysfunction in children with sleep-disordered breathing.

STUDY OBJECTIVES: To measure sympathetic responses in children with and without sleep-disordered breathing. DESIGN: Prospective, observational study. SETTING: Kosair Children's Hospital Sleep Medicine and Apnea Center. PARTICIPANTS: Subjects were prospectively recruited from children undergoing overnight polysomnographic assessments and were retrospectively grouped according to the results of the polysomnogram. Sleep-disordered breathing was defined as an apnea-hypopnea index >5 and children were assigned to the control group if their apnea-hypopnea index was < 1. INTERVENTION: N/A. MEASUREMENTS AND RESULTS: During quiet wakefulness, pulse arterial tonometry was used to assess changes in sympathetic activity following vital capacity sighs in 28 children with sleep-disordered breathing and 29 controls. Each child underwent a series of 3 sighs, and the average maximal pulse arterial tonometry signal attenuation was calculated. Further, a cold pressor test was conducted in a subset of 14 children with sleep-disordered breathing and 14 controls. The left hand was immersed in ice cold water for 30 seconds while right-hand pulse arterial tonometry signal was continuously monitored during immersion and 20-minute recovery periods. Signal amplitude changes were expressed as percentage change from corresponding baseline. RESULTS: The magnitude of sympathetic discharge-induced attenuation of pulse arterial tonometry signal was significantly increased in children with sleep-disordered breathing during sigh maneuvers (74.1% +/- 10.7% change compared with 59.2% +/- 13.2% change in controls; P<.0001) and the cold pressor test (83.5% +/- 7.3% change compared with 74.1% +/- 11.4% change in controls; P=.039). Further, recovery kinetics in control children were faster than those of children with sleep-disordered breathing. CONCLUSION: Children with sleep-disordered breathing have altered autonomic nervous system regulation as evidenced by increased sympathetic vascular reactivity during wakefulness.

Adolescent↗

PubMedDate not supplied

Diabetes mellitus and autonomic dysfunction after vacor rodenticide ingestion.

A case of N-3 pyridylmethyl-N' 4 nitrophenyl urea (Vacor) rodenticide poisoning in a 52-year-old man is presented. Vacor is structurally related to alloxan and streptozotocin, agents that have been used extensively to produce diabetes mellitus in laboratory animals. Seven days after ingestion of Vacor, the patient presented in diabetic ketoacidosis complicated by postural hypotension and adynamic ileus. The patient recovered from ketoacidosis but has continued to require insulin. With infusion of arginine, glucagon rose from 185 to 650 pg./ml. and C-peptide from 0.5 to 3.4 ng./ml. Six weeks after onset of diabetes, no anti-islet-cell antibodies were detected. Muscle capillary basement membrane thickness on electron microscopy was found to be 1,918 +/- 194 A. The absence of hyperglycemia after Vacor ingestion should not lead to complacency on the part of the attending physician. The patient must be observed closely for development of ketoacidosis and treated prophylactically with nicotinamide, the suggested antidote.

Autonomic Nervous System↗

PubMed1999

Autonomic dysfunction in end-stage liver disease manifested as defecation syncope: impact of orthotopic liver transplantation.

Patients with end-stage liver disease (ESLD) may be at increased risk for syncopal episodes based on their circulatory physiological state. Although a definitive cause for this is not known, several mechanisms have been proposed. In patients with ESLD, defecation syncope may result from a failure of short-term neurocirculatory adaptation to the Valsalva maneuver in the face of a hyperdynamic circulatory state and a decreased effective intravascular volume. We describe 2 patients with ESLD who had repeated episodes of defecation syncope before orthotopic liver transplantation (OLT). The most effective treatment of these syncopal episodes appears to be fluid administration and the use of a pressor agent, such as dopamine, to help maintain both an effective heart rate and intravascular volume. Correction of this altered circulatory physiological state through OLT prevented further syncopal episodes in both patients. A search of the literature failed to show previous reports associating ESLD and defecation syncope. Possible mechanisms favoring this association are reviewed.

Adult↗

PubMed1980

Substance P in human cerebrospinal fluid: reductions in peripheral neuropathy and autonomic dysfunction.

Substance P (SP), a putative peptide neurotransmitter, was measured in human lumbar cerebrospinal fluid (CSF) by radioimmunoassay. Substance P-like immunoreactivity (SPLI) was present in the CSF of 18 neurologically normal adults in concentrations ranging from 2.9 to 11.1 fmol per milliliter, with a mean of 7.0 /+- 0.6 fmol per milliliter (mean /+- SE). Slightly more than half of the CSF-SPLI cochromatographed with synthetic SP on Sephadex G-25. There was no apparent gradient in CSF-SPLI concentration over the first 30 ml of CSF removed by lumbar puncture. Mean concentrations CSF-SPLI in patients with Huntington disease, parkinsonism, miscellaneous dyskinesias, progressive supranuclear palsy, myopathy, and amyotrophic lateral sclerosis did not differ significantly from normal. Patients with neuropathy or multiple-system atrophy (Shy-Drager syndrome) had significantly reduced mean CSF-SPLI concentrations. These observations suggest that lumbar CSF-SPLI arises largely from spinal cord, nerve roots, or dorsal root ganglia, and that pathologic processes affecting these structures may be reflected by reduced levels of CSF-SPLI.

Adolescent↗

PubMedDate not supplied

Autonomic dysfunction in Chagas disease: lack of participation of the vagus nerve.

To evaluate the possible role of the vagus nerve in the development of the dysautonomia in Chagas disease, we examined 18 nerves from chagasic patients and 8 from non-chagasic patients, autopsied at the Department of Pathology, Ribeirão Preto School of Medicine, Brazil. Histological analysis showed mild inflammatory infiltrate composed predominantly of T lymphocytes, in epi-, peri- and endoneurium. No parasites were observed. Semithin sections showed swollen unmyelinated fibres, occasional thinly myelinated fibres, degenerated and atrophic axons, related to myelinated fibres. These findings were confirmed by electron microscopy, and in teased fibres. The changes were observed both in chagasic and in non-chagasic patients. Statistical analysis of the morphometric findings (myelinated fibre density, axonal and fibre diameters) failed to show significant differences between the 2 groups. The frequency of myelinated fibres of various diameters was also similar in the 2 groups. The morphological and morphometrical findings in chagasic patients are mild, non-specific, and could be related to the age of the patients, or with artefacts, since they have also been observed in non-chagasic patients. Retrograde changes due to the ganglionic lesions in the innervated organs cannot be completely ruled out. Our results do not allow us to implicate the vagus nerve in the dysautonomia in Chagas disease.

Age Distribution↗