Sympathetic Autonomic Dysfunction Research Articles

Effect of α-blockers on Handgrip Test Response of Diastolic Blood Pressure in Hypertensive, Benign Hypertrophy of Prostate Patients in a Therapeutics Clinic, Kolkata: A Cross-sectional Study.

The isometric handgrip (IHG) test is commonly used to detect sympathetic autonomic dysfunction. Tamsulosin, approved for the management of symptomatic benign prostatic hyperplasia (BPH), acts as an antagonist for α1-adrenergic receptors (α1-AR), whereas prazosin, an α1 receptor blocker, being less selective than tamsulosin, is used as an antihypertensive agent clinically. Our objective was to investigate if there is a distinction in blood pressure (BP) increase during IHG exercise between individuals with essential hypertension taking tamsulosin compared to those taking prazosin. A cross-sectional observational study was performed on 50 subjects receiving tablet prazosin and 47 subjects receiving tamsulosin, who were asked to undergo an IHG test. Pre- and posttest BP was recorded for both the groups, and the difference in diastolic BP (DBP) (delta DBP) was compared between the groups and to their respective baseline values. Post-IHG test, mean DBP was found to be 93.98 ± 9.13 mm Hg in the prazosin group and 101.00 ± 12.05 mm Hg in the tamsulosin group, respectively. The change of delta DBP in the tamsulosin group was significant, but the prazosin group showed an insignificant rise in DBP. Prazosin, being less selective than tamsulosin in terms of α1 receptor antagonism, showed suppression of BP during IHG. Tamsulosin demonstrates high selectivity for prostatic receptors while showing minimal affinity for vascular receptors. As a result, its impact on BP is expected to be minimal.

Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients

Several disabling symptoms potentially related to dysautonomia have been reported in “long-COVID” patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31–43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0–16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

Unilateral erythema in a newborn

A 10-day-old newborn male was referred to our clinic for the evaluation of congenital dermal melanocytosis. During the physical examination, when the baby was lying on his side, a sharply demarcated erythema involving half of his body was noticed (Figure 1). The change of colour lasted a few minutes. The baby was otherwise healthy, and no additional signs were observed. The baby's mother reported only one other isolated similar episode of about the same duration occurring at home when the baby was lying naked on the changing table. HP is a rare event that consists of a sudden unilateral transient change in skin colour with a sharp demarcation along the body midline, resulting in two different body colours.1 HP usually occurs between the 3rd and 4th day of life, and typically appears when the baby is lying on the side and may last from 30 s up to 20 min. It can be a single event or it can be recurrent. Newborns can experience several episodes in just a few days.2 Pathophysiology of HP is still not completely clear although there is evidence to support a sympathetic autonomic dysfunction, probably because of hypothalamic immaturity in the newborn.2 HP represents a benign condition although it has also been reported in the context of hypoxia and as an epiphenomenon of central nervous system disorders such as meningitis, hypothalamic and brain stem lesions or sympathetic nervous system lesions. Exacerbation has been described in patients receiving treatment with prostaglandin E1.1, 3 While the clinical characteristics of HP make it easily distinguishable, a differential diagnosis should include infectious neonatal skin rashes, such as parechovirus, herpes virus and candida infection, neonatal lupus erythematosus and capillary malformations such as those in the PROS spectrum and cutis marmorata telangiectatica congenita. HP can be a manifestation of the rare disorder paroxysmal extreme pain disorder, part of SCN9A neuropathic pain syndromes, a group of sodium channelopathies where systemic symptoms such as tonic nonepileptic attacks and syncope with bradycardia are associated with the transient skin colour change.4 HP is a benign and self-resolving phenomenon. As mentioned, only in rare circumstances HP is a manifestation of central nervous system disorders in association with other signs and symptoms and never presenting as the sole clue of such conditions.5 The recognition of the phenomenon is therefore important since, while being certainly peculiar, it does not require further investigations or therapeutic measures. Alice Nadia Rossi wrote the first draft of the manuscript and adjusted it according to the comments of the other authors. Francesco Paolo Salamone collected data and clinical images and helped writing the manuscript. Martina Mussi participated in data collection. Marco Adriano Chessa participated in the revision of the manuscript. Iria Neri carried out the final revision of the manuscript before submission. All of the authors participated in the preparation of the manuscript. There are no prior publications or submissions with any overlapping information, including studies and patients. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The authors declare no conflicts of interest. All patients in this manuscript have given written informed consent for participation in the study and the use of their de-identified, anonymized, aggregated data and their case details (including photographs) for publication. Data sharing is not applicable to this article as no new data were created or analysed in this study.

Association of Cardiac Autonomic Function Derangement with Obesity and Glycated Haemoglobin: A Cross-sectional Study

Introduction: Hyperglycaemia (as assessed by Glycated haemoglobin (HbA1c)) and obesity lead to the production of advanced glycation end products in blood, which are responsible for damage to the microvasculature, slowly leading to cardiac autonomic dysfunction. Thus, chronic prediabetic hyperglycaemia, as measured by HbA1c may affect cardiac autonomic function in different ranges of obesity (overweight and obese). Aim: To study the association of cardiac autonomic dysfunction with Body Mass Index (BMI) and HbA1c. Materials and Methods: The cross-sectional study was conducted at BPS Government Medical College, Sonepat, Haryana, India, from June to December 2019. This study included age and sex-matched 50 healthy, 50 overweight, and 50 obese subjects aged 18-50 years. Serum HbA1c, lipid profile and cardiac autonomic function tests for the parasympathetic system (Resting heart rate, Expiration-inspiration difference on deep breathing, Heart rate response to standing/30:15 stand ratio, Valsalva ratio) and sympathetic system {postural hypotension/fall in Systolic Blood Pressure (SBP) and change in Diastolic Blood Pressure (DBP) on sustained hand grip test} were performed. Chi-square test and Mann-Whitney test were used for statistical analysis. Results: The prevalence of sympathetic autonomic dysfunction was highest in the obese group (36% in males n=25, and 32% in females, n=25) followed by overweight group (12% in males, n=25 and 12% in females, n=25). The prevalence of parasympathetic autonomic dysfunction was highest in the obese group (40% in males, n=25 and 32% in females, n=25), followed by the overweight group (24% in males, n=25 and 16% in females, n=25). Further, HbA1c was highest in obese males (6.27±1.54) and females (5.94±0.45), followed by overweight males (5.89±0.92) and females (5.46±1.84). Males and females with autonomic dysfunction had significantly higher HbA1c (Males 6.4±0.42 and Females 6.2±0.38) than those without it (Males 5.4±0.86 and Females 5.2±0.75) in the obese and overweight groups taken together. Conclusion: The prevalence of parasympathetic and sympathetic dysfunction is incrementally increased with higher obesity (BMI) and HbA1c. Overweight and obese subjects with cardiac autonomic dysfunction had higher HbA1c and worse lipid profiles than overweight and obese subjects without autonomic dysfunction.

The Effect of High Temperature on Cardiovascular Autonomic Function Tests in Steel Plant Furnace Worker

Background:The high temperature in the working environment could be one of the risk factors for cardiovascular diseases in steel plant workers. The excessive high temperature at the working place leads to altered autonomic activity and is related to more cardiovascular risk.Aims and Objectives:The effect of high temperature on cardiovascular autonomic function tests in steel plant furnace worker.Material and Method:This was a case-control study for which 50 steel plant furnace workers and 50 controls were selected. The cardiovascular sympathetic function status in worker and control were analyzed by three tests: (i) Blood pressure (BP) response to sustained isometric handgrip test, (ii) BP response to the cold pressor test, and (iii) BP response to standing from a supine position (orthostasis). Statistical analysis was done by using an independent t-test.Results:Diastolic BP (DBP) response to sustained isometric handgrip and systolic BP (SBP) and DBP response to the cold pressor test showed that the increase BP in workers were more than controls but the difference was not statistically significant (P > 0.05). SBP response to standing from the supine position showed statistically significant (P < 0.001) greater fall in steel plant workers.Conclusion:The sympathetic autonomic dysfunction was seen in steel furnace workers in response to environmental stressor–excessive heat.

Autonomic function assessment in Egyptian patients with Behçet's disease

Background Behçet's disease (BD) is considered a chronic multisystem disorder, where neurological manifestations are common. There is scarcity of investigations that have assessed the autonomic nervous system dysfunction in BD, with conflicting results. Objectives The current study aimed to identify presence of autonomic nervous system dysfunction using neurophysiological assessment in BD and to investigate the relationship between the indicators of autonomic function and the disease activity parameters. Patients and methods The study involved 30 patients with BD in accordance with the Universal Criteria for Behçet's Diseases and 25 controls, who were subjected to clinical evaluation and Palmar sympathetic skin response (SSR). Results Patients with BD had a significant difference in SSR (P&lt;0.001) compared with controls. Moreover, a significant positive association was found among neuropathic pain and disease activity parameters. Conclusion The study confirms the presence of sympathetic autonomic dysfunction in BD, which related to disease activity using a simple noninvasive test such as SSR.

Reappraising Diabetic Foot Ulcers: A Focus on Mechanisms of Ulceration and Clinical Evaluation.

Diabetic foot ulcers (DFU) are one of the most devastating complications of diabetes as they have significant effects on patient morbidity and mortality. Since their first description in the 19th century, our understanding of DFU has evolved as we uncover the mechanisms that mediate ulceration. In this review, we aim to summarize the various pathways that lead to the development of DFU in order to reappraise physicians' understanding of these complex wounds. Relevant pathways include the following: (1) neuropathy (motor neuropathy, loss of protective sensation, and autonomic sympathetic dysfunction), (2) vascular disease (arterial ischemia, venous insufficiency, and microvascular changes), and (3) metabolism (signaling and immunological effects of hyperglycemia). We also discuss the clinical presentation of DFU and an evidence-based evaluation to assist clinicians in early identification and classification of these wounds to inform management of DFU. Finally, we summarize complications of DFU caused by the various pathways mediating ulceration and briefly overview DFU management in order to educate physicians about the potential risks if left untreated. A better understanding of the synergistic pathways leading to DFU is essential for clinicians to improve DFU diagnosis, tailor intervention, and mitigate significant patient morbidity and mortality.

Central Noradrenergic Agonists in the Treatment of Ischemic Stroke-an Overview.

Ischemic stroke is the leading cause of morbidity and mortality with a significant health burden worldwide and few treatment options. Among the short- and long-term effects of ischemic stroke is the cardiovascular sympathetic autonomic dysfunction, presented in part as the by-product of the ischemic damage to the noradrenergic centers of the brain. Unlike high levels in the plasma, the brain may face suboptimal levels of norepinephrine (NE), with adverse effects on the clinical and functional outcomes of ischemic stroke. The intravenous administration of NE and other sympathomimetic agents, in an attempt to increase cerebral perfusion pressure, often aggravates the ischemia-induced rise in blood pressure (BP) with life-threatening consequences for stroke patients, the majority of whom present with hypertension at the time of admission. Unlike the systemic administration, the central administration of NE reduces BP while exerting anti-inflammatory and neuroprotective effects. These characteristics of centrally administered NE, combined with the short latency of response, make it an ideal candidate for use in the acute phase of stroke, followed by the use of centrally acting noradrenergic agonists, such as NE reuptake inhibitors and B2-adrenergic receptor agonists for stroke rehabilitation. In addition, a number of nonpharmacological strategies, such as transcutaneous vagus nerve stimulation (tVNS) and trigeminal nerve stimulation (TNS), have the potential to enhance the central noradrenergic functional activities and improve stroke clinical outcomes. Many factors could influence the efficacy of the noradrenergic treatment in stroke patients. These factors include the type of the noradrenergic agent; the dose, frequency, and duration of administration; the timing of administration in relation to the acute event; and the site and characteristics of the ischemic lesions. Having this knowledge, combined with the better understanding of the regulation of noradrenergic receptors in different parts of the brain, would pave the path for the successful use of the centrally acting noradrenergic agents in the management of ischemic stroke.

Non-invasive evaluation of sudomotor function in patients with myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease associated with antibodies against the nicotinic muscle acetylcholine receptor (AChR) at the neuromuscular junction. Dysautonomia has been previously described in MG. Electrochemical skin conductance (ESC), assessed by Sudoscan®, is a non-invasive method that allows evaluation of sudomotor function. Since sweat glands are innervated by sudomotor, postganglionic, cholinergic sympathetic C-fibers, we hypothesized that ESC could be a reliable method for assessing autonomic dysfunction in MG. ESC measurements were prospectively assessed in patients with generalized MG and in healthy controls. Patients with diabetes mellitus, anticholinergic medication or electrophysiological findings of peripheral neuropathy were excluded. Data regarding demographic and disease features were collected. Presence of autonomic symptoms in patients with MG was assessed by Compass-31. For statistical analysis we performed student t-test and Chi2 test for comparison between both groups. We included 24 patients (mean age of 46.4±10.6, 75% women, mean disease duration 12.5 years, 62.5% positive for AChR antibodies) and 37 controls. We found no difference in either foot (P=0.13) or hand (P=0.83) ESC measurements between patients and controls, even after correcting for age. We could not prove the presence of autonomic sympathetic dysfunction in our cohort of MG patients when assessed by Sudoscan®. In addition, Compass-31 was not a useful questionnaire in this clinical context.

Peripheral autonomic sympathetic dysfunction in rheumatoid arthritis in the absence of traditional cardiovascular risk

Peripheral autonomic sympathetic dysfunction in rheumatoid arthritis in the absence of traditional cardiovascular risk

A Study to Evaluate the Involvement of Parasympathetic Nervous System in Tension Type Headache

Context: Headache is one of the most common disorders of the nervous system seen in medical practice. Tension-type headache although most prevalent is yet understudied subtype of primary headache known to cause substantial disability and diminished quality of life in patients. The neurobiology of symptoms in tension-type headache is still speculated. A few studies done earlier have suggested sympathetic autonomic dysfunction associated with etiopathogenesis of tension-type headache. Altered stress reactivity of autonomic nervous system is now known to be associated with increased risk of cardiovascular mortality. Objectives: There is a lack of data as regards involvement of parasympathetic limb of autonomic nervous system in tension type headache patients especially in the Indian population. The objective of the study is to evaluate the involvement of parasympathetic nervous system in tension type headache. Methods: Various parasympathetic function tests were done to assess the parasympathetic activity in 50 tension-type headache patients. The evaluation was done by standard, bedside, non-invasive tests like deep breathing test, Valsalva manoeuvre and orthostatic test. The reference values of Ewing and Clark were used to interpret the results of the test. ­­­­­Results: In the present study the basal heart rate was significantly decreased in tension type headache patients as compared to healthy controls. However parasympathetic function as evaluated by the different tests was found to be normal as compared to controls. Conclusion: We conclude that the decrease in resting heart rate in tension type headache patients could be suggestive of sympathetic hypo function as reported by previous studies. However parasympathetic function is unaltered in tension type headache patients. Key words: Parasympathetic nervous system, Deep breathing test, Valsalva manoeuvre, Orthostatic test, TTH

Sympathetic autonomic dysfunction and impaired cardiovascular performance in higher risk surgical patients: implications for perioperative sympatholysis

ObjectiveRecent perioperative trials have highlighted the urgent need for a better understanding of why sympatholytic drugs intended to reduce myocardial injury are paradoxically associated with harm (stroke, myocardial infarction). We...

Impact of sympathetic dysfunction in the etiology of overactive bladder in women: A preliminary study

We investigated the effects of autonomic sympathetic dysfunction in the etiology of overactive bladder (OAB) in women, by assessing the sympathetic skin response (SSR). In total, 40 women with OAB and 15 volunteers were enrolled. Group 1 (n = 20) consisted of patients who benefitted from oral anticholinergics, Group 2 (n = 20) consisted of patients who were refractory to oral anticholinergics, and the volunteers (n = 15) were the control group. All patients were asked to complete OAB-SF questionnaires. The absence of SSR was accepted as significant. Detailed physical examinations including neurological examinations were performed. All patients underwent SSR tests on the skin of the hands, feet, and genital area in our neurology department using electromyography, and SSR responses were recorded. Statistical significance was accepted at P < 0.05. The mean age was 47.2 ± 12.4 years. In total, 55 women were evaluated (20 in Group 1, 20 in Group 2, and 15 in the control group). Mean OAB scores were similar between groups 1 and 2, although urgency was significantly higher in Group 2 than 1. The absence of SSR was significantly higher in Group 2 than 1 (P = 0.01). Impaired SSR was observed more commonly in Group 2 than 1. All controls had normal SSRs. Regional dysfunction in the autonomic nervous system may be part of OAB's etiology. SSR may be a candidate test for determining early OAB, and may also be useful for predicting antimuscarinic-refractory patients.

Migraine with cranial autonomic features following surgically induced post-ganglionic sympathetic lesion

Although not typically considered as part of the clinical phenotype of migraine, cranial autonomic symptoms, such as lacrimation or conjunctival injection, can certainly occur. Their appearance can lead to the common misdiagnosis of sinus headache in clinical practice. The patient presented developed post-ganglionic sympathetic denervation at the level of the superior cervical ganglion/carotid plexus. Her subsequent partial Horner's syndrome symptoms intensified during subsequent migraine attacks indicating increasing sympathetic autonomic dysfunction. At the time of the pain, recruitment and activation of the trigeminal autonomic reflex were demonstrated by lacrimation. The clinical picture suggests peripheral unmasking of the underlying central trigeminal autonomic reflex that is active in migraine. Recognition of cranial autonomic symptoms in migraine is a key to confident differential diagnosis from trigeminal autonomic cephalalgias and from sinus-related headache disorders.

Autonomic nervous system dysfunction and serum levels of neurotoxic and neurotrophic cytokines in patients with cobalamin deficiency.

The imbalance between neurotoxic cytokine tumor necrosis factor-α (TNF-α) and neurotrophic cytokines epidermal growth factor (EGF) and interleukin-6 (IL-6) plays a role in the pathogenesis of cobalamin (Cbl) deficiency-induced neuropathy. The aim of this study was to evaluate autonomic nervous system dysfunction and to look for any relationship between autonomic nervous system disturbances and serum cytokine levels (TNF-α, EGF, IL-6) in patients with Cbl deficiency. Serum levels of TNF-α, EGF and IL-6 were studied in patients with Cbl deficiency (n=41) and a healthy control group (n=17) and after 3 months in patients who underwent Cbl replacement therapy (n=22). All patients with Cbl deficiency underwent electrophysiological studies (EPS) for the diagnosis of neuropathy. Statistical analysis was performed using SPSS for Windows 11.5 software. With EPS, 29 of 41 Cbl-deficient patients (70.73%) demonstrated neurological dysfunction [3 (7.32%), 19 (46.34%) and 7 (17.07%) patients with sensorimotor peripheral neuropathy, parasympathetic, and sympathetic autonomic dysfunction, respectively]. Although there was no significant difference in serum levels of EGF and IL-6 between patients with versus without autonomic dysfunction, levels were significantly lower in Cbl- deficient patients than healthy controls. Presence of autonomic dysfunction seems to be a frequent neurological finding in patients with Cbl deficiency. However, we could not find any relationship between serum cytokine levels and autonomic dysfunction by EPS.

Autonomic Abnormalities in Cyclic Vomiting Syndrome

Although cyclic vomiting syndrome (CVS) is associated with migraine, and migraine in turn is associated with orthostatic tachycardia, few studies have explored the association of CVS and autonomic dysfunction. We describe the results of autonomic testing in 6 children with characteristic CVS. All patients fully met the established criteria for the diagnosis of CVS, were well hydrated, and were beyond their episode of vomiting. We performed 3 tests of cardiovascular function and 1 sudomotor test, using standard previously published methods. The findings were surprisingly uniform, with normal cardiovascular responses to deep breathing and to the Valsalva maneuver in all patients, a significant increase in heart rate (>30 beats per minute) with tilt testing, and a vasodepressor tendency in 2 patients. Interestingly, abdominal pain occurred at blood pressure nadir in both these patients and in a third patient without the vasodepressor findings but who described syncope clinically. Sudomotor test results were abnormal in all 6 patients, with reduced responses in 5 of 6 and exaggerated responses in the 6th. All 6 patients reported a personal or family history of migraine headaches. CVS is associated with remarkably uniform primarily sympathetic autonomic dysfunction, affecting mainly the vasomotor and sudomotor systems, and compatible with an underlying autonomic neuropathy. The occurrence of symptoms during tilt testing in half the patients suggests that these findings may play a true pathophysiologic role. A vagally modulated sympathetic effect is postulated as the best mechanistic model to account for all current physiologic data on cyclic vomiting and gastroparesis.

Autonomic dysfunction in primary biliary cirrhosis correlates with fatigue severity

Autonomic dysfunction has previously been described in primary biliary cirrhosis patients. In nonhepatic diseases, fatigue is associated with autonomic dysfunction and impaired baroreflex sensitivity. Here, we investigate the prevalence of autonomic dysfunction using highly sensitive detection modalities and its relationship with fatigue in both noncirrhotic and cirrhotic primary biliary cirrhosis patients. Autonomic reflex tests were performed, using continuous blood pressure and electrocardiograph measurement in 47 primary biliary cirrhosis patients and age and sex-matched controls. Fatigue was measured using the primary biliary cirrhosis-40. In all, 100% of precirrhotic and 81% of cirrhotic primary biliary cirrhosis patients exhibited autonomic dysfunction. Valsalva ratio and 30 : 15 ratio (measures of parasympathetic autonomic dysfunction) were significantly lower in primary biliary cirrhosis patients than in controls (valsalva ratio: 1.42 vs. 1.57; P=0.01, 30 : 15: 1.1 vs. 1.2; P=0.01). Blood pressure drop on standing (sympathetic autonomic dysfunction) was greater in the primary biliary cirrhosis group (31+/-22 vs. 23+/-15 mmHg; P=0.03). Valsalva phase IV size was similar between primary biliary cirrhosis patients and controls, however, time to phase IV was significantly longer (P=0.01), suggesting adrenergic failure. Increasing fatigue was associated with impaired baroreflex sensitivity and an earlier, bigger phase IV (sympathetic overactivity). No significant differences were seen, between cirrhotic and noncirrhotic patients. The prevalence of autonomic dysfunction in primary biliary cirrhosis patients is significantly higher than has previously been thought to be the case. Indeed, when sensitive detection modalities are used, it is found to be almost universal at all stages of the disease process. Fatigue in primary biliary cirrhosis is associated with abnormalities of autonomic function.

Autonomic dysfunction and impaired cerebral autoregulation in cirrhosis

Cerebral blood flow autoregulation is lost in patients with severe liver cirrhosis. The cause of this is unknown. We determined whether autonomic dysfunction was related to impaired cerebral autoregulation in patients with cirrhosis. Fourteen patients with liver cirrhosis and 11 healthy volunteers were recruited. Autonomic function was assessed in response to deep breathing, head-up tilt and during 24-h Holter monitoring. Cerebral autoregulation was assessed by determining the change in mean cerebral blood flow velocity (MCAVm, transcranial Doppler) during an increase in blood pressure induced by norepinephrine infusion (NE). The severity of liver disease was assessed using the Child-Pugh scale (class A, mild; class B, moderate; class C, severe liver dysfunction).NE increased blood pressure similarly in the controls (27 (24-32) mmHg) and patients with the most severe liver cirrhosis (Child-Pugh C, 31 (26-44) mmHg, p=0.405 Mann-Whitney). However, the increase in MCAVm was greater in cirrhosis patients compared to the controls (Child-Pugh C, 26 (24-39) %; controls, 3 (-1.3 to 3) %; respectively, p=0.016, Mann-Whitney). HRV during deep breathing was reduced in the cirrhosis patients (Child-Pugh C, 6.0+/-2.0 bpm) compared to the controls (21.7+/-2.2 bpm, p=0.001, Tukey' test). Systolic blood pressure fell during head-up tilt only in patients with severe cirrhosis. Our results imply that cerebral autoregulation was impaired in the most severe cases of liver cirrhosis, and that those with impaired cerebral autoregulation also had severe parasympathetic and sympathetic autonomic dysfunction. Furthermore, the degree of liver dysfunction was associated with increasing severity of autonomic dysfunction. Although this association is not necessarily causal, we postulate that the loss of sympathetic innervation to the cerebral resistance vessels may contribute to the impairment of cerebral autoregulation in patients with end-stage liver disease.

Vasomotor rhinitis update

This review was conducted to examine new data on vasomotor rhinitis, a common clinical problem. Recent publications highlight advances in the study of the pathophysiology of vasomotor rhinitis. Electron microscopic and ultracytochemical evaluation of the nasal mucosa in vasomotor rhinitis demonstrates an emerging role of neuropeptides and nitric oxide in the pathogenesis of vasomotor rhinitis. Ozone, cigarette smoke, and other environmental factors may trigger neurogenic mechanisms that lead to vasomotor rhinitis. Objective tests have documented the presence of hypoactive sympathetic autonomic dysfunction. Such assessments also suggest autonomic dysfunction as a possible link between vasomotor rhinitis and gastroesophageal reflux disease. Recent publications propose nasal secretory protein analysis as a possible diagnostic tool. Evidence-based review of treatment outcomes shows topical sprays of azelastine, budesonide, and ipratropium to be of benefit in vasomotor rhinitis. A better understanding of the role of nitric oxide and neuropeptides in the pathogenesis of vasomotor rhinitis has opened new avenues in research, diagnosis, and management. Clinical diagnosis may be aided by the analysis of nasal secretory proteins. Effective treatments include antihistamine, anticholinergics, and steroid nasal sprays.

Detection of autonomic sympathetic dysfunction in diabetic patients. A study using laser Doppler imaging.

To study signs of the disturbed reflex autonomic sympathetic nerve function in type 1 and type 2 diabetic patients. Measurements were made on 15 type 1 (duration 13-32 years) and on 50 recently diagnosed type 2 diabetic patients (duration 3-4 years). The vasoconstrictor responses in the distal phalanx of the middle finger (locally heated to 40 degrees C) to the cooling of the contralateral arm were measured using Laser Doppler Imaging (LDI). A vasoconstriction index (VAC) was calculated taking age into account and was compared with reference values obtained in 80 control subjects. The diabetic patients were also studied with deep-breathing tests (i.e., the heart-rate variation expressed as the expiration-to-inspiration [E/I] ratio, a test of parasympathetic nerve function). The vasoconstrictor responses to indirect cooling (VAC) were significantly reduced in the fingers of the diabetic patients, both type 2 (0.77 +/- 0.02 V; P < 0.01) and type 1 (0.83 +/- 0.04 V; P < 0.001), compared with the healthy control subjects (0.65 +/- 0.01); the age-corrected VAC (VACz) was slightly more impaired in type 1 than in type 2 diabetic patients. The frequency of an abnormal VACz corresponded well to the frequency of an abnormal E/I ratio in type 1 diabetic patients (approximately 50%), whereas the frequency of an abnormal VACz was significantly higher than an abnormal E/I ratio among type 2 diabetic patients (11/50 vs. 4/50; P < 0.05). Both type 1 and type 2 diabetic patients have impaired cutaneous blood flow regulation. The VAC index seems to be a promising tool for detection of subclinical changes in autonomic sympathetic function.