The Pseudodystonia of Paroxysmal Sympathetic Hyperactivity: A Reversible Post-Anoxic Complication.
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ABSTRACT:
SUBMITTER: Gupta HV
PROVIDER: S-EPMC7604657 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Introduction: Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a severe form of stiff-person spectrum disorder characterized by painful spasms, myoclonic jerks, hyperekplexia, brainstem dysfunction, and dysautonomia, which is sometimes resistant to γ-amino-butyric acid (GABA)-ergic agents. The response to immunotherapy varies depending on identified autoantibodies. We report a dramatic response to dexmedetomidine in a patient with glycine receptor (GlyR) antibody-positive PERM who developed intractable clusters of myoclonic jerks and paroxysmal sympathetic hyperactivity (PSH) that was highly refractory to conventional symptomatic treatment with GABAergic drugs and immunotherapy. Case Presentation: A 62-year-old Japanese man was transferred to our center for intermittent painful spasms that progressed in severity over the preceding 7 weeks. On admission, he had gaze-evoked nystagmus, and paroxysmal painful spasms/myoclonic jerks triggered by sound or touch. The myoclonic jerks rapidly worsened, along with the development of hyperekplexia, opisthotonus, and PSH, leading to prolonged apnea requiring mechanical ventilation. Brain and spinal cord magnetic resonance imaging was unremarkable. Cerebrospinal fluid (CSF) examination revealed mild pleocytosis and oligoclonal bands. Surface electromyography confirmed simultaneous agonist-antagonist continuous motor unit activity. Based on the clinico-electrophysiological features, PERM was suspected. He was initially treated with intravenous steroids, immunoglobulin, benzodiazepines, and propofol, but the symptoms persisted. On day 9, he received a continuous infusion of dexmedetomidine, which resulted in dramatic reduction in the frequency of clusters of myoclonic jerks and PSH. The effect of dexmedetomidine was confirmed by surface electromyography. The addition of plasma exchange resulted in further clinical improvement. GlyR antibodies were identified in the CSF but not the serum, leading to the diagnosis of GlyR antibody-positive PERM. Conclusions: PERM is an immune-mediated disorder, but dexmedetomidine, a highly selective α2-adrenergic agonist, may alleviate paroxysmal symptoms by decreasing noradrenergic neuronal activity, resulting in attenuation of antibody-mediated disinhibited increased motor and sympathetic activity. Dexmedetomidine may be useful as an adjunctive symptomatic therapy in PERM and related disorders.
| S-EPMC8311021 | biostudies-literature
Project description:BackgroundParoxysmal sympathetic hyperactivity (PSH) results and aggravates in secondary brain injury, which seriously affects the prognosis of severe traumatic brain injury patients. Although several studies have focused on the treatment of PSH, few have concentrated on its prevention.MethodsNinety post-operation (post-op) severe traumatic brain injury (sTBI) patients admitted from October 2014 to April 2016 were chosen to participate in this study. Fifty of the post-op sTBI patients were sedated with dexmedetomidine and were referred as the "dexmedetomidine group" (admitted from May 2015 to April 2016). The other 40 patients (admitted from October 2014 to May 2015) received other sedations and were referred as the "control group." The two groups were then compared based on their PSH scores and the scores and ratios of those patients who met the criteria of "probable," "possible" and "unlikely" using the PSH assessment measure (PSH-AM) designed by Baguley et al. (2014). The durations of the neurosurgery intensive care unit (NICU) and hospital stays and the Glasgow outcome scale (GOS) values for the two groups were also compared to evaluate the therapeutic effects and the patients' prognosis.ResultsThe overall PSH score for the dexmedetomidine group was 5.26 ± 4.66, compared with 8.58 ± 8.09 for the control group. The difference between the two groups' PSH scores was significant (P = 0.017). The score of the patients who met the criterion of "probable" was 18.33 ± 1.53 in the dexmedetomidine group and 22.63 ± 2.97 in the control group, and the difference was statistically significant (P = 0.045). The ratio of patients who were classified as "unlikely" between the two groups was statistically significant (P = 0.028); that is, 42 (84%) in the dexmedetomidine group and 25 (62.5%) in the control group. The differences in NICU, hospital stays and GOS values between the two groups were not significant.ConclusionDexmedetomidine has a preventive effect on PSH in sTBI patients who have undergone surgery.
| S-EPMC5314954 | biostudies-literature
Project description:Cardiovascular disease is the most prevalent age-related illness worldwide, causing approximately 15 million deaths every year. Hypertension is central in determining cardiovascular risk and is a strong predictive indicator of morbidity and mortality; however, there remains an unmet clinical need for disease-modifying and prophylactic interventions. Enhanced sympathetic activity is a well-established contributor to the pathophysiology of hypertension, however the cellular and molecular changes that increase sympathetic neurotransmission are not known. The aim of this study was to identify key changes in the transcriptome in normotensive and spontaneously hypertensive rats. We validated 15 of our top-scoring genes using qRT-PCR, and network and enrichment analyses suggest that glutamatergic signalling plays a key role in modulating Ca2+ balance within these ganglia. Additionally, phosphodiesterase activity was found to be altered in stellates obtained from the hypertensive rat, suggesting that impaired cyclic nucleotide signalling may contribute to disturbed Ca2+ homeostasis and sympathetic hyperactivity in hypertension. We have also confirmed the presence of these transcripts in human donor stellate samples, suggesting that key genes coupled to neurotransmission are conserved. The data described here may provide novel targets for future interventions aimed at treating sympathetic hyperactivity associated with cardiovascular disease and other dysautonomias.
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Project description:Sympathetic nerve hyperactivity is a primary reason for fatal ventricular arrhythmias (VAs) following myocardial infarction (MI). Pro-inflammatory cytokines produced in the paraventricular nucleus (PVN) post-MI are associated with sympathetic overexcitation; however, the precise mechanism needs further investigation. Our aim was to explore the mechanism of toll-like receptor 4 (TLR4) and its downstream molecular pathway in mediating sympathetic activity post-MI within the PVN. A rat MI model was developed via left anterior descending coronary artery ligation. TLR4 was primarily localized in microglia and increased markedly within the PVN at 3 days in MI rats. Sympathoexcitation also increased, as indicated by high levels of renal sympathetic nerve activity (RSNA) and norepinephrine (NE) concentration. TLR4 knockdown via shRNA microinjection to the PVN resulted in decreased activation of Fos protein (+) neurons in the PVN and peripheral sympathetic nerve activity. TLR4 knockdown also exhibited a lower arrhythmia score following programmed electrical stimulation than those treated with MI surgery only, indicating that the knockdown of TLR4 decreased the incidence of malignant ventricular arrhythmias following MI. LPS-induced inflammatory response was analyzed to explore the underlying mechanism of TLR4 in sympathetic hyperactivity. High levels of NF-κB protein, the pro-inflammatory cytokines IL-1β and TNF-α, and ROS production were observed in the LPS group. PVN-targeted injection of the NF-κB inhibitor PDTC attenuated NF-κB expression and sympathetic activity. Taken together, the results suggested that knockdown of microglial TLR4 within the PVN decreased sympathetic hyperactivity and subsequent VAs post-MI. The downstream NF-κB pathway and ROS production participated in the process. Interventions targeting TLR4 signaling in the PVN may be a novel approach to ameliorate the incidence of VAs post-MI.
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Project description:Aldosterone has been shown to exert a central sympathoexcitatory action in multiple animal models, but evidence in humans is still lacking.Our objective was to determine whether hyperaldosteronism causes reversible sympathetic activation in humans.We performed a cross-sectional comparison of muscle sympathetic nerve activity (SNA, intraneural microelectrodes) in 14 hypertensive patients with biochemically proven primary aldosteronism (PA) with 20 patients with essential hypertension (EH) and 18 age-matched normotensive (NT) controls. Seven patients with aldosterone-producing adenoma (APA) were restudied 1 month after unilateral adrenalectomy.Mean blood pressure values in patients with PA and EH and NT controls was 145 ± 4/88 ± 2, 150 ± 4/90 ± 2, and 119 ± 2/76 ± 2 mm Hg, respectively. The major new findings are 2-fold: 1) baseline SNA was significantly higher in the PA than the NT group (40 ± 3 vs. 30 ± 2 bursts/min, P = 0.014) but similar to the EH group (41 ± 3 bursts/min) and 2) after unilateral adrenalectomy for APA, SNA decreased significantly from 38 ± 5 to 27 ± 4 bursts/min (P = 0.01), plasma aldosterone levels fell from 72.4 ± 20.3 to 11.4 ± 2.3 ng/dl (P < 0.01), and blood pressure decreased from 155 ± 8/94 ± 3 to 117 ± 4/77 ± 2 mm Hg (P < 0.01).These data provide the first evidence in humans that APA is accompanied by reversible sympathetic overactivity, which may contribute to the accelerated hypertensive target organ disease in this condition.
| S-EPMC3050103 | biostudies-literature
Project description:Sympathetic neurons of the rat superior cervical ganglion (SCG) can segregate their neurotransmitters and co-transmitters to separate varicosities of single axons. We have shown that transmitter segregation is a plastic phenomenon and that it is correlated with the strength of synaptic transmission. Here, we determined whether sympathetic dysfunction occurring in stress and hypertension was correlated with plastic changes of neurotransmitter segregation. We characterized the expression of the markers, L-glutamic acid decarboxylase of 67 kDa (GAD67) and vesicular acetylcholine (ACh) transporter (VAChT) in the SCG of cold stressed and spontaneously hypertensive rats (SHR). Considering that the SCG comprises a heterogeneous neuronal population, we explored whether the expression and segregation of neurotransmitters would also have an intraganglionic heterogeneous distribution in ganglia of stressed and hypertensive rats. Furthermore, since hypertension in SHR is detected around 8-10 weeks, we evaluated expression and segregation of ACh and GABA in adult hypertensive (12-week old (wo)) and young pre-hypertensive (6-wo) SHR. We found an increase in segregation of ACh and GABA with no change in transmitter expression in ganglia of stressed animals. In contrast, in SHR, there was an increase in GABA expression, although segregation did not vary. Segregation showed a caudo-rostral gradient in controls but not in the ganglia of stressed animals. GABA expression showed a rostro-caudal gradient in adult SHR, which was not present in young 6-wo rats. In young SHR, ACh increased and, unexpectedly, segregation of ACh and GABA was higher than in adults. Data suggest that ACh and GABA segregation increases in acute sympathetic hyperactivity like stress, but does not vary in chronic hyperactivity such as in hypertension. Changes in segregation are age-dependent and might be involved in the mechanisms underlying stress and hypertension.
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Project description:Although much is known about environmental factors that predispose individuals to hypertension and cardiovascular disease, little information is available regarding the genetic and signaling events involved. Indeed, few genes associated with the progression of these pathologies have been discovered despite intensive research in animal models and human populations. Here we identify Vav3, a GDP-GTP exchange factor that stimulates Rho and Rac GTPases, as an essential factor regulating the homeostasis of the cardiovascular system. Vav3-deficient mice exhibited tachycardia, systemic arterial hypertension and extensive cardiovascular remodeling. These mice also showed hyperactivity of sympathetic neurons from the time of birth. The high catecholamine levels associated with this condition led to the activation of the renin-angiotensin system, increased levels of kidney-related hormones and the progressive loss of cardiovascular and renal homeostasis. Pharmacological studies with drugs targeting sympathetic and renin-angiotensin responses confirmed the causative role and hierarchy of these events in the development of the Vav3-null mouse phenotype. These observations uncover the crucial role of Vav3 in the regulation of the sympathetic nervous system (SNS) and cardiovascular physiology, and reveal a signaling pathway that could be involved in the pathophysiology of human disease states involving tachycardia and sympathetic hyperactivity with unknown etiologies.
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Project description:Familial dysautonomia (FD), a rare neurodevelopmental and neurodegenerative disorder affects the sympathetic and sensory nervous system. Although almost all patients harbor a mutation in ELP1, it remains unresolved exactly how function of sympathetic neurons (symNs) is affected; knowledge critical for understanding debilitating disease hallmarks, including cardiovascular instability or dysautonomic crises, that result from dysregulated sympathetic activity. Here, we employ the human pluripotent stem cell (hPSC) system to understand symN disease mechanisms and test candidate drugs. FD symNs are intrinsically hyperactive in vitro, in cardiomyocyte co-cultures, and in animal models. We report reduced norepinephrine transporter expression, decreased intracellular norepinephrine (NE), decreased NE re-uptake, and excessive extracellular NE in FD symNs. SymN hyperactivity is not a direct ELP1 mutation result, but may connect to NET via RAB proteins. We found that candidate drugs lowered hyperactivity independent of ELP1 modulation. Our findings may have implications for other symN disorders and may allow future drug testing and discovery.
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Project description:A 9-year-old girl with a ten-day history of palpitations was referred for the assessment of mitral regurgitation. She had had RF ablation for paroxysmal supraventricular tachycardia 5 years previously. Echocardiography showed isolated anterior mitral leaflet perforation. Surgical findings confirmed the echocardiographic assessment.
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Project description:Serum neurofilament light (sNfL) is a promising marker of outcome after cardiac arrest, but its kinetics are unclear. We prospectively measured sNfL concentrations in 62 patients at 0, 1, 3, 5, 7 and 10 days after cardiac arrest. Survivors and non-survivors had similar sNfL at admission (14.2 [8.6-21.9] vs. 22.5 [14.2-46.9] pg/mL) but largely different at 24 h (16.4 [10.2-293] vs. 464.3 [151.8-1658.2], respectively). The AUC for sNfL concentrations predicting death was above 0.95 from Day 1 to 10 (highest on Day 3). Late sNfL measurements may exert prognostic value, especially when early samples are unavailable or prognosis remains unclear.
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