Cutaneous sympathetic function in patients with multiple system atrophy

Rapid, Large, and Synchronous Sweat and Cardiovascular Responses Upon Minor Stimuli in Healthy Subjects. Dynamics and Reproducibility

Purpose: The aim of the study was to investigate steady state levels, dynamics and reproducibility of cardiovascular variables and electrodermal activity in different skin areas in response to minor physiological and mental stimuli in healthy subjects in the thermoneutral zone, carried out in high time resolution. Methods: Thirteen healthy subjects underwent experiments on two separate days. Non-invasive electrodermal activity in five different skin areas was measured continuously using a skin conductance method, including resting supine and sitting positions, performing deep inspirations, a mental challenge and being exposed to a sudden loud sound. Blood pressure, heart rate, radial artery blood flow, and skin perfusion were measured simultaneously. Results: Electrodermal activity in the right and left palms was almost identical, with rapid and large increases within a few seconds in response to stimuli, whereas no such significant changes were seen in the face, back, and abdomen. Radial artery blood flow and palmar skin perfusion changed synchronously with electrodermal activity for each stimulus, and were correlated to changes in blood pressure and heart rate. The response patterns in each subject were very similar on the two experimental days. There was very low spontaneous electrodermal activity in the supine position, contrary to the resting sitting position. Conclusion: The electrodermal activity increased rapidly and synchronously in both palms within a few seconds as a response to minor physiological and mental stimuli, synchronous with fluctuations in radial artery blood flow, palmar skin perfusion, and cardiovascular variables. The responses are reproducible from day to day, making them a stable and constant stimuli to be used for studies in patients with hyperhidrosis.

The Effect of Different Physiological Stimuli on Skin Vasomotor Reflexes above and below the Lesion in Human Chronic Spinal Cord Injury

Objective. Spinal cord injury (SCI) results in disruption of descending tonic activation of sympathetic circuits in the spinal cord. The authors determined whether different stimuli that increase sympathetic activity induced cutaneous vasoconstriction (skin vasomotor reflex, SkVR) above and below the level of lesion in subjects with clinically complete SCI. Methods. Baseline skin blood flow (SkBF) and SkVR reduction rate in the pulp of the finger and great toe was measured by laser Doppler probes in chronic complete SCI and in controls. Results. In the finger, baseline SkBF was similar in SCI and controls. The SkVR was elicited by all stimuli in controls but was significantly diminished to gasp, mental arithmetic, tactile stimulation, cutaneous cold, and deep breathing in high SCI compared to controls. In the toe, baseline SkBF was less stable in both controls and SCI. SkVR trends were identified in controls, and responses were not present or greatly reduced in high and low SCI. Conclusions. Measurements of skin vasomotor reflexes to physiological stimuli may be a noninvasive method to evaluate the extent of sympathetic adrenergic pathways in chronic SCI. This is of clinical relevance in monitoring recovery of sympathetic adrenergic function either spontaneously or following repair interventions.

Skin sympathetic function in complex regional pain syndrome type 1

PURPOSE

Cutaneous sympathetic pathophysiology in complex regional pain syndrome type 1 (CRPS-1) is not yet completely understood. To evaluate cutaneous sympathetic dysfunction in CRPS-1, we evaluated sympathetic sweat response (SSwR) and skin vasomotor reflex (SkVR) in CRPS-1 patients.

METHODS

We studied 10 CRPS-1 patients (age 41 ± 13 years; 5 females and 5 males; disease duration 20 ± 22 months) and 10 healthy subjects (age 44 ± 13 years; 3 females and 7 males). SkVRs and SSwRs to several sympathetic activating procedures were recorded on the palms of the CRPS-1 patients (affected side) and controls (right side).

RESULTS

There were no significant differences in the baselines of sweat output and skin blood flow between the CRPS-1 and control groups. SSwR and SkVR amplitudes were significantly lower in the CRPS-1 group than in the control group. There was no significant correlation between disease duration and SSwR or SkVR amplitudes among the patients.

CONCLUSIONS

The reduced SSwRs and SkVRs in the affected limb of our CRPS-1 patients may reflect underlying damage to the sympathetic postganglionic fibres.

[Evaluation of sudomotor function]

From the aspect of physiological roles, sweating on the hairy skin is an important for thermoregulation of body, and that on glabrous skin (the palm or sole) works as an anti-skid material when gripping something or performing a delicate task using the fingertips (emotional sweating). Abnormal sweating, which can be global or localized, is classified into hyperhidrosis and hypohidrosis, and detection of abnormal sweating, such as Horner's syndrome and Harlequin syndrome, is clinically useful for regional diagnosis of neurological lesions. In addition, sudomotor function tests, where sweat secretion is induced by physiological or pharmacological stimuli, are useful for diagnosis of neurological disorders. In this manuscript, clinical evaluation of abnormal sweating from the aspect of neurological diagnosis is reviewed.

Investigation of antimuscarinic receptor autoantibodies in patients with acquired idiopathic generalized anhidrosis

OBJECTIVE

The autoimmune mechanism is considered to play an important role in the development of acquired idiopathic generalized anhidrosis (AIGA), and muscarinic M3 receptors (M3Rs) on eccrine glands are possible autoimmune targets. We investigated the existence of autoantibodies against M3Rs in AIGA patients.

METHODS

We immunostained M3R-expressing cultured cells with the serum of 12 AIGA patients (mean age: 35.0±11.7 years, mean disease duration: 26.6±25.8 months) and 10 healthy subjects (mean age: 32.4±10.4 years).

RESULTS

The surface of the M3R-expressing cells was stained by the serum obtained from one of the 12 AIGA patients but not by the serum obtained from the remaining 11 patients or healthy subjects.

CONCLUSION

The presence of M3R autoantibodies may therefore be related to the underlying mechanism of disease in a subset of AIGA patients.

Peripheral vascular response to inspiratory breath hold in paediatric homozygous sickle cell disease

New Findings

• What is the central question of this study?

Autonomic nervous dysfunction is implicated in complications of sickle cell anaemia (SCA). In healthy adults, a deep inspiratory breath hold (IBH) elicits rapid transient SNS- mediated vasoconstriction detectable using Laser Doppler Flux (LDF) assessment of the finger-tip cutaneous micovasculature.

• What is the main finding and its importance?

We demonstrate significantly increased resting peripheral blood flow and sympathetic activity in African children with SCA compared to sibling controls and increased sympathetic stimulation in response to vasoprovocation with DIG.

This study is the first to observe an inverse association between resting peripheral blood flow and haemoglobin oxygen saturation (SpO2). These phenomena may be an adaptive response to the hypoxic exposure in SCA.

There is increasing evidence that autonomic dysfunction in adults with homozygous sickle cell (haemoglobin SS) disease is associated with enhanced autonomic nervous system-mediated control of microvascular perfusion. However, it is unclear whether such differences are detectable in children with SS disease. We studied 65 children with SS disease [38 boys; median age 7.2 (interquartile range 5.1–10.6) years] and 20 control children without symptoms of SS disease [8 boys; 8.7 (5.5–10.8) years] and recorded mean arterial blood pressure (ABP) and daytime haemoglobin oxygen saturation (). Cutaneous blood flux at rest (RBF) and during the sympathetically activated vasoconstrictor response to inspiratory breath hold (IBH) were measured in the finger pulp of the non-dominant hand using laser Doppler fluximetry. Local factors mediating flow motion were assessed by power spectral density analysis of the oscillatory components of the laser Doppler signal. The RBF measured across the two study groups was negatively associated with age (r=−0.25, P < 0.0001), ABP (r=−0.27, P= 0.02) and daytime (r=−0.30, P= 0.005). Children with SS disease had a higher RBF (P= 0.005) and enhanced vasoconstrictor response to IBH (P= 0.002) compared with control children. In children with SS disease, higher RBF was associated with an increase in the sympathetic interval (r=−0.28, P= 0.022). The SS disease status, daytime and age explained 22% of the variance in vasoconstrictor response to IBH (P < 0.0001). Our findings suggest that blood flow and blood flow responses in the skin of young African children with SS disease differ from those of healthy control children, with increased resting peripheral blood flow and increased sympathetic stimulation from a young age in SS disease. They further suggest that the laser Doppler flowmetry technique with inspiratory breath hold manoeuvre appears to be robust for use in young children with SS disease, to explore interactions between , ABP and autonomic function with clinical complications, e.g. skin ulceration.

Preserved autonomic function in patients with POEMS syndrome

AIM

We systematically performed autonomic testing on patients with polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes syndrome (POEMS) to determine whether autonomic function is preserved in such patients.

METHODS

We studied 17 POEMS patients, 17 diabetic neuropathy (DN) patients and 17 age-matched normal subjects. Blood pressure responses to the head-up tilt test and heart rate variability were used to evaluate cardiovascular autonomic function. Sweat responses and cutaneous vasoconstriction to several stimuli were recorded via the finger tips to estimate cutaneous sympathetic function. In addition, motor nerve conduction studies were performed.

RESULTS

Although the results of the autonomic testing were normal in POEMS patients, motor disability was severe, and motor nerve conduction studies provided evidence of extensive axonal loss. The DN patients showed significantly impaired autonomic responses despite mild motor dysfunction.

CONCLUSIONS

Autonomic function was normal in POEMS patients, indicating the preservation of autonomic fibers and selective involvement of large fibers.

Diminished emotional sweating in patients with limbic encephalitis

OBJECTIVE

Sweating on the palms of the hands and soles of the feet, so-called emotional sweating, is considered to be mediated by the limbic system, including the amygdala and anterior cingulate cortex. To reveal involvement of the limbic system in emotional sweating, we evaluated emotional sweating on the palms in patients with limbic encephalitis.

METHODS

Sweat and skin vasoconstriction responses to arousal stimuli were recorded on the palms of 7 patients with limbic encephalitis caused by viral infection (n=3) or immune-mediated encephalitis (n=4). All patients had amnesia, and magnetic resonance imaging revealed mesial temporal lobe lesions, including those on the amygdala, in 6 of these patients.

RESULTS

Sweat responses were absent or markedly reduced in patients with limbic encephalitis compared to normal controls following deep inspiration (p<0.05), mental arithmetic (p<0.01), exercise (p<0.05), and tactile stimulation (p<0.01). Skin vasoconstriction responses in these patients were also impaired, but the extent of such impairment was mild compared to that of the sweating reductions.

CONCLUSION

Sweating on the palm was significantly impaired in patients with mesial temporal lesions. Sweating on the palm could be a useful index of limbic function.

Measurements of sweat response and skin vasomotor reflex for assessment of autonomic dysfunction in patients with diabetes

AIMS

Some physical or arousal stimuli induce a rise in sweat secretion (sympathetic sweat response or SSwR) and a reduction in skin blood flow (skin vasomotor reflex or SkVR) to the palm. We recorded SSwRs and SkVRs in diabetic patients and assessed the usefulness of these parameters for evaluating autonomic dysfunction in diabetes.

METHODS

We studied 42 diabetic patients (58+/-12 years) and 42 normal control subjects (59+/-11 years). Focal sweat secretion and skin blood flow were measured on the palm by a sudorometer and a Doppler flowmeter, respectively. SSwRs and SkVRs to deep inspiration, mental arithmetic, and isotonic exercise were recorded. SSwR amplitude was measured from baseline to peak, and SkVR amplitude (reduction rate) was calculated as: (blood flow reduction/basal blood flow)x100%. We also conducted head-up tilt tests and R-R interval variation tests (coefficient of variation of R-R intervals or CV(R-R)).

RESULTS

The SSwR or SkVR amplitudes in the diabetic group were significantly lower than those in the control group for any stimulus. CV(R-R) in the diabetic group was significantly less than that in the control group. The diabetic group showed a significantly greater reduction in systolic blood pressure during head-up tilt compared with the control group. In the diabetic group, there were significant correlations in SSwR or SkVR amplitudes versus blood pressure falls during the head-up tilt test, and CV(R-R) values.

CONCLUSION

We believe that SSwR and SkVR are useful indexes for the evaluation of autonomic involvement in diabetic patients.

Sympathetic sweat responses and skin vasomotor reflexes in carpal tunnel syndrome

OBJECTIVE

To investigate cutaneous sympathetic functions in carpal tunnel syndrome (CTS) using sympathetic sweat responses (SSwRs) and skin vasomotor reflexes (SVmRs).

METHODS

In 29 hands (20 patients) with idiopathic CTS, SSwRs were recorded with a sudorometer from the thenar eminence, and SVmRs were used to measure cutaneous blood flow using a Doppler flowmeter placed on the index finger tip. Normal data were obtained from 15 volunteers of similar age.

RESULTS

SSwRs or SVmRs were abnormal in 23 (80%) hands; SSwRs were absent in 38%, whereas SVmRs were abnormally decreased in 59%. Autonomic symptoms were present in 18 (62%) hands; finger edema (38%) and dry hand (35%) were frequent symptoms. Autonomic symptoms, and abnormal SSwRs and SVmRs did not correlate with results of nerve conduction studies.

CONCLUSIONS

Skin sudomotor or vasomotor sympathetic function is frequently impaired in CTS. Susceptibility to compression ischemia may be different in sympathetic unmyelinated and large myelinated fibers.

Skin vasodilator response to local heating in multiple system atrophy

Local heating of nonglabrous skin increases skin blood flow (SkBF) in two phases. The initial peak (P1) is mediated by a sensory-axon reflex and the plateau phase (P2) by local production of substances such as nitric oxide. We evaluated the SkBF response to local heating in 15 multiple system atrophy (MSA) patients with autonomic failure and 12 age-matched healthy controls. The mean ratio of SkBF at P1 to that at baseline (SkBF(P1)/SkBF(base) ratio) in MSA was significantly lower than that in controls (P < 0.01). The mean ratio of SkBF at P2 seemed to be slightly reduced in the MSA patients, compared with controls, although there was no significant difference. The P1 phase is thought to be mediated by a sensory-axon reflex modulated by sympathetic nerve activity. These findings are indicative of the skin sympathetic vasomotor dysfunction in MSA.

The raphe magnus/pallidus regulates sweat secretion and skin vasodilation of the cat forepaw pad: A preliminary electrical stimulation study

In the human palm/sole, mental or physical stimuli induce an increase in sweat secretion and a decrease in skin blood flow (SkBF). However, the central pathways of these responses remain unclear. We measured sweat secretion and SkBF in the cat footpad by electrically stimulating the raphe. Stimulation of the rostral raphe magnus/pallidus elicited a reduction in SkBF without affecting sweat secretion. Stimulation of the mid to caudal raphe magnus/pallidus elicited an increase in both sweat secretion and SkBF. The raphe magnus/pallidus may play a crucial role in skin vasomotor and sudomotor responses in the cat footpad.

Skin vasomotor reflex responses in two contrasting groups of autonomic failure

BACKGROUND & AIM

A variety of stimuli such as deep inspiration, isometric exercise and mental arithmetic, result in a transient vasoconstriction,mediated by sympathetic efferent nerves, in the skin of the fingers and toes of healthy controls (Skin Vasomotor Reflex: SkVR). Multiple system atrophy (MSA) and pure autonomic failure (PAF) provide contrasting models of autonomic failure. In MSA the lesion is central and preganglionic, whilst in PAF the lesion site is peripheral and postganglionic. We evaluated the SkVR in response to various stimuli in MSA and PAF, to determine differences in skin vasomotor involvement between these two patient groups.

METHODS

25 subjects (10 MSA, 7 PAF, 8 healthy controls) were studied. Baseline recordings of skin blood flow were obtained with a laser Doppler probe on the left index finger pulp and forearm. The subject then underwent a variety of stimuli with rest periods in between to reestablish baseline SkBF. These stimuli were: single deep inspiration (inspiratory gasp); mental arithmetic; bilateral leg elevation and cutaneous cold.

RESULTS

Healthy control subjects demonstrated marked SkVRs on the finger pulp to each of the stimuli of a magnitude similar to those seen in previous studies, but no SkVRs on the forearm. In MSA SkVRs to inspiratory gasp on the finger pulp were reduced relative to controls. In PAF SkVRs were reduced relative to controls or MSA. The magnitude of SkVR response to gasp and cutaneous cold in PAF was significantly less than in healthy controls. In addition, the magnitude of the response in PAF was significantly less than in MSA for inspiratory gasp.

CONCLUSIONS

PAF showed a decreased SkVR response to all 4 stimuli, the response being significantly less than controls (for inspiratory gasp and cutaneous cold) or MSA (cutaneous cold inspiratory gasp). The decreased responses in PAF may reflect the extensive postganglionic sympathetic denervation seen in this group. The measurement of SkVR may therefore provide a non-invasive aid to the differentiation of MSA and PAF.

Pyridostigmine in autonomic failure: can we treat postural hypotension and bladder dysfunction with one drug?

In a 66-year-old man with autonomic failure, pyridostigmine (180 mg/day orally) improved both postural hypotension and underactive detrusor bladder dysfunction. Acetylcholinesterase inhibition may be useful in the management of orthostatic hypotension and bladder dysfunction in autonomic failure patients.

Cutaneous sympathetic function and cardiovascular function in patients with progressive supranuclear palsy and Parkinson's disease

Some procedures, such as deep inspiration, increase sweat output (SSwR; sympathetic sweat response) and reduce cutaneous blood flow (SVR; skin vasomotor reflex) on the palm. We investigated SSwR, SVR, and cardiovascular function in 12 patients with progressive supranuclear palsy (PSP), 13 patients with Parkinson's disease (PD), and 9 healthy subjects. In the PSP patients, SSwR was severely diminished, whereas SVR was maintained and cardiovascular function was well preserved. In the PD patients, SSwR was relatively preserved, SVR was maintained, and some patients showed cardiovascular hypofunction. A combination of skin sympathetic and cardiovascular tests may be useful for distinguishing between PD and PSP.