Hyperbaric Oxygen Therapy in the Management of Paroxysmal Sympathetic Hyperactivity After Severe Traumatic Brain Injury: A Report of 6 Cases

Non-pharmacological interventions for traumatic brain injury

Heterogeneity and variability of symptoms due to the type, site, age, sex, and severity of injury make each case of traumatic brain injury (TBI) unique. Considering this, a universal treatment strategy may not be fruitful in managing outcomes after TBI. Most of the pharmacological therapies for TBI aim at modifying a particular pathway or molecular process in the sequelae of secondary injury rather than a holistic approach. On the other hand, non-pharmacological interventions such as hypothermia, hyperbaric oxygen, preconditioning with dietary adaptations, exercise, environmental enrichment, deep brain stimulation, decompressive craniectomy, probiotic use, gene therapy, music therapy, and stem cell therapy can promote healing by modulating multiple neuroprotective mechanisms. In this review, we discussed the major non-pharmacological interventions that are being tested in animal models of TBI as well as in clinical trials. We evaluated the functional outcomes of various interventions with an emphasis on the links between molecular mechanisms and outcomes after TBI.

A Modern Approach to the Treatment of Traumatic Brain Injury

Background: Traumatic brain injury manifests itself in various forms, ranging from mild impairment of consciousness to severe coma and death. Traumatic brain injury remains one of the leading causes of morbidity and mortality. Currently, there is no therapy to reverse the effects associated with traumatic brain injury. New neuroprotective treatments for severe traumatic brain injury have not achieved significant clinical success. Methods: A literature review was performed to summarize the recent interdisciplinary findings on management of traumatic brain injury from both clinical and experimental perspective. Results: In the present review, we discuss the concepts of traditional and new approaches to treatment of traumatic brain injury. The recent development of different drug delivery approaches to the central nervous system is also discussed. Conclusions: The management of traumatic brain injury could be aimed either at the pathological mechanisms initiating the secondary brain injury or alleviating the symptoms accompanying the injury. In many cases, however, the treatment should be complex and include a variety of medical interventions and combination therapy.

Neutrophil extracellular traps facilitate sympathetic hyperactivity by polarizing microglia toward M1 phenotype after traumatic brain injury

Traumatic brain injury (TBI), particularly diffuse axonal injury (DAI), often results in sympathetic hyperactivity, which can exacerbate the prognosis of TBI patients. A key component of this process is the role of neutrophils in causing neuroinflammation after TBI by forming neutrophil extracellular traps (NETs), but the connection between NETs and sympathetic excitation following TBI remains unclear. Utilizing a DAI rat model, the current investigation examined the role of NETs and the HMGB1/JNK/AP1 signaling pathway in this process. The findings revealed that sympathetic excitability intensifies and peaks 3 days post-injury, a pattern mirrored by the activation of microglia, and the escalated NETs and HMGB1 levels. Subsequent in vitro exploration validated that HMGB1 fosters microglial activation via the JNK/AP1 pathway. Moreover, in vivo experimentation revealed that the application of anti-HMGB1 and AP1 inhibitors can mitigate microglial M1 polarization post-DAI, effectively curtailing sympathetic hyperactivity. Therefore, this research elucidates that post-TBI, NETs within the PVN may precipitate sympathetic hyperactivity by stimulating M1 microglial polarization through the HMGB1/JNK/AP1 pathway.

Pharmacological Management of Paroxysmal Sympathetic Hyperactivity: A Scoping Review

Paroxysmal sympathetic hyperactivity (PSH) occurs in ∼10% of patients following acute severe brain injury. While PSH is associated with worse outcomes, there are no clinical practice guidelines to inform treatment. We aimed to systematically review the literature on the pharmacological management of PSH. MEDLINE, Embase, and Cochrane library databases were searched from inception to August 2020. Eligible studies met the following criteria: 1) randomized controlled trials, non-randomized controlled trials (case control or controlled cohort), observational studies, case series, and case reports; 2) study population of adult and pediatric patients; 3) exposure to an acute neurological insult complicated by PSH (or historic synonym); 4) description of pharmacological treatment of PSH. Our search retrieved 2729 citations with 83 articles assessed for inclusion. After full text extraction, 56 manuscripts inclusive of 459 patients met eligibility criteria. We identified 31 case reports, 15 case series (152 patients), seven retrospective case control or cohort studies (212 patients), and three prospective observational studies (52 patients). Traumatic brain injury was the most common precipitating insult (407 patients), followed by hypoxic encephalopathy (72 patients) and intracranial hemorrhage (10 patients). There were 48 drugs from 22 classes prescribed for the management of PSH. The most frequently prescribed agents were benzodiazepines, β-blockers, opioids, α-2 agonists, and baclofen. However, route and dose of drug and subsequent outcome were inconsistently reported, such that no summary was possible. While a wide variety of drugs have been reported to treat PSH, there is a lack of even moderate-quality evidence to inform clinical decision making.

NETs Lead to Sympathetic Hyperactivity After Traumatic Brain Injury Through the LL37-Hippo/MST1 Pathway

Background: Paroxysmal sympathetic hyperactivity (PSH) is one of the important reasons for the high mortality and morbidity of traumatic brain injury (TBI). We aim to explore the role of the neutrophil extracellular traps (NETs) in the pathogenesis of sympathetic hyperexcitability after TBI and the underlying mechanisms, providing evidence for clinical treatment.

Methods: Enzyme-linked immunosorbent assay was used to assess the plasma metanephrine and normetanephrine levels which represented the variation of the sympathetic system after TBI with rat diffuse axonal injury (DAI) model. NETs in the paraventricular nucleus (PVN) and circulating blood were examined using immunofluorescence and flow cytometry. Neutrophils-microglia co-culture system was established to further explore the effect of NETs on PSH and its mechanisms.

Results: After TBI, metanephrine and normetanephrine levels began to increase at 9 h and peaked at 72 h. After the injury, the level of NETs kept increasing at 24 and 72 h in the PVN. A positive correlation was found between the concentration of the PVN NETs and blood catecholamine. Flow cytometry of peripheral blood cells revealed that NETs level in the injury group was higher than that in the control group. Immunofluorescence results confirmed the presence of NETs in the PVN after TBI. The positive result of immunoprecipitation suggested a correlation effect between LL37 and P2 × 7. Peptidyl arginine deiminase-4 (PAD4) inhibitor could inhibit the expression levels of MST1, YAP, and IL-1β. The hippo/MST1 pathway inhibitor could inhibit the expression levels of YAP and IL-1β.

Conclusion: NETs formation in the PVN might be associated with sympathetic hyperactivity after TBI, which might relate to the activation of microglia cells and increased secretion of IL-1β via the hippo/MST1 pathway.

The Role of Iron, Its Metabolism and Ferroptosis in Traumatic Brain Injury

Traumatic brain injury (TBI) is a structural and physiological disruption of brain function caused by external forces. It is a major cause of death and disability for patients worldwide. TBI includes both primary and secondary impairments. Iron overload and ferroptosis highly involved in the pathophysiological process of secondary brain injury. Ferroptosis is a form of regulatory cell death, as increased iron accumulation in the brain leads to lipid peroxidation, reactive oxygen species (ROS) production, mitochondrial dysfunction and neuroinflammatory responses, resulting in cellular and neuronal damage. For this reason, eliminating factors like iron deposition and inhibiting lipid peroxidation may be a promising therapy. Iron chelators can be used to eliminate excess iron and to alleviate some of the clinical manifestations of TBI. In this review we will focus on the mechanisms of iron and ferroptosis involving the manifestations of TBI, broaden our understanding of the use of iron chelators for TBI. Through this review, we were able to better find novel clinical therapeutic directions for further TBI study.

Identification and Management of Paroxysmal Sympathetic Hyperactivity After Traumatic Brain Injury

Paroxysmal sympathetic hyperactivity (PSH) has predominantly been described after traumatic brain injury (TBI), which is associated with hyperthermia, hypertension, tachycardia, tachypnea, diaphoresis, dystonia (hypertonia or spasticity), and even motor features such as extensor/flexion posturing. Despite the pathophysiology of PSH not being completely understood, most researchers gradually agree that PSH is driven by the loss of the inhibition of excitation in the sympathetic nervous system without parasympathetic involvement. Recently, advances in the clinical and diagnostic features of PSH in TBI patients have reached a broad clinical consensus in many neurology departments. These advances should provide a more unanimous foundation for the systematic research on this clinical syndrome and its clear management. Clinically, a great deal of attention has been paid to the definition and diagnostic criteria, epidemiology and pathophysiology, symptomatic treatment, and prevention and control of secondary brain injury of PSH in TBI patients. Potential benefits of treatment for PSH may result from the three main goals: eliminating predisposing causes, mitigating excessive sympathetic outflow, and supportive therapy. However, individual pathophysiological differences, therapeutic responses and outcomes, and precision medicine approaches to PSH management are varied and inconsistent between studies. Further, many potential therapeutic drugs might suppress manifestations of PSH in the process of TBI treatment. The purpose of this review is to present current and comprehensive studies of the identification of PSH after TBI in the early stage and provide a framework for symptomatic management of TBI patients with PSH.

Review of clinical nerve repair strategies for neurorestoration of central nervous system tumor damage

Central nervous system (CNS) tumors are common. In recent years, with the continuous development and popularization of neurosurgery and the advancement of diagnostic and therapeutic instruments, the diagnosis and treatment of diseases have made great progress, but the prognosis of patients depends on multiple clinical factors. In this study, we selected various literatures in the PubMed and Google Scholar search engines using the keywords "nerve repair strategies" , "central nervous system tumor" as well as searched scientifically reviewed historical perspectives and recent advancements and achievements in Neurorestoratology of the CNS. Therefore, this study focuses on the Neurorestoratology of the CNS and its prospects, aiming to provide scientific guidance for the clinical diagnosis and treatment of CNS tumors in the future, and improve the prognosis and quality of life of patients.

Tracheostomy as a Risk Factor for Paroxysmal Sympathetic Hyperactivity in Severe Traumatic Brain Injury

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) is an uncommon complication of severe traumatic brain injury (sTBI). The clinical risk factors for PSH have not been fully characterized, especially regarding tracheostomy, which has usually been recommended for patients with sTBI to facilitate treatment. We examined the effects of tracheostomy on PSH incidence in patients with sTBI.

METHODS

The present single-center, retrospective study included consecutive patients with sTBI who had been admitted to the Shanghai Changzheng Hospital from January 1, 2013 to March 31, 2018. The potential risk factors related to the occurrence of PSH was explored by univariate analysis. Multivariate logistic regression analysis was conducted to determine the independence of the factors associated with PSH development.

RESULTS

Of the 120 patients with sTBI, 17 with PSH were identified (14.16%). We found 3 risk factors were significantly associated with PSH on univariate and multivariate analyses: 1) tracheostomy (odds ratio [OR], 5.368; 95% confidence interval [CI], 1.102-26.151; P = 0.038); 2) age (OR, 0.916; 95% CI, 0.874-0.960; P < 0.001); and 3) hydrocephalus (OR, 6.715; 95% CI, 1.708-26.408; P = 0.006).

CONCLUSIONS

Our results suggest that tracheostomy is independently associated with an increased incidence of PSH.

Is Hyperbaric Oxygen Therapy Effective for Traumatic Brain Injury? A Rapid Evidence Assessment of the Literature and Recommendations for the Field

Supplemental Digital Content is Available in the Text.

Objective:

This systematic review examines the efficacy of hyperbaric oxygen (HBO₂) for traumatic brain injury (TBI) to make evidence-based recommendations for its application and future research.

Methods:

A comprehensive search was conducted to identify studies through 2014. Methodological quality was assessed and synthesis and interpretation of relevant data was performed.

Results:

Twelve randomized trials were included. All mild TBI studies demonstrated minimal bias and no statistically significant differences between HBO₂ and sham arms. Statistically significant improvement occurred over time within both groups. Moderate-to-severe TBI studies were of mixed quality, with majority of results favoring HBO₂ compared with “standard care.” The placebo analysis conducted was limited by lack of details.

Conclusions:

For mild TBI, results indicate HBO₂ is no better than sham treatment. Improvements within both HBO₂ and sham groups cannot be ignored. For acute treatment of moderate-to-severe TBI, although methodology appears flawed across some studies, because of the complexity of brain injury, HBO₂ may be beneficial as a relatively safe adjunctive therapy if feasible. Further research should be considered to resolve the controversy surrounding this field, but only if methodological flaws are avoided and bias minimized.

Paroxysmal sympathetic hyperactivity: the storm after acute brain injury

A substantial minority of patients who survive an acquired brain injury develop a state of sympathetic hyperactivity that can persist for weeks or months, consisting of periodic episodes of increased heart rate and blood pressure, sweating, hyperthermia, and motor posturing, often in response to external stimuli. The unifying term for the syndrome-paroxysmal sympathetic hyperactivity (PSH)-and clear diagnostic criteria defined by expert consensus were only recently established. PSH has predominantly been described after traumatic brain injury (TBI), in which it is associated with worse outcomes. The pathophysiology of the condition is not completely understood, although most researchers consider it to be a disconnection syndrome with paroxysms driven by a loss of inhibitory control over excitatory autonomic centres. Although therapeutic strategies to alleviate sympathetic outbursts have been proposed, their effects on PSH are inconsistent between patients and their influence on outcome is unknown. Combinations of drugs are frequently used and are chosen on the basis of local custom, rather than on objective evidence. New rigorous tools for diagnosis could allow better characterisation of PSH to enable stratification of patients for future therapeutic trials.

Rehabilitation Treatment and Progress of Traumatic Brain Injury Dysfunction

Traumatic brain injury (TBI) is a major cause of chronic disability. Worldwide, it is the leading cause of disability in the under 40s. Behavioral problems, mood, cognition, particularly memory, attention, and executive function are commonly impaired by TBI. Spending to assist, TBI survivors with disabilities are estimated to be costly per year. Such impaired functional outcomes following TBI can be improved via various rehabilitative approaches. The objective of the present paper is to review the current rehabilitation treatment of traumatic brain injury in adults.

Hyperbaric oxygen therapy for traumatic brain injury: bench-to-bedside

Traumatic brain injury (TBI) is a serious public health problem in the United States. Survivors of TBI are often left with significant cognitive, behavioral, and communicative disabilities. So far there is no effective treatment/intervention in the daily clinical practice for TBI patients. The protective effects of hyperbaric oxygen therapy (HBOT) have been proved in stroke; however, its efficiency in TBI remains controversial. In this review, we will summarize the results of HBOT in experimental and clinical TBI, elaborate the mechanisms, and bring out our current understanding and opinions for future studies.

Paroxysmal Sympathetic Hyperactivity in a Child with Tuberculous Meningitis A Case Study and Review of Related Literature

A one-year old boy was admitted to hospital for lethargy and vomiting over three days. Neurological examination revealed abnormalities. Cerebrospinal fluid examination showed evidence of meningitis. A purified protein derivative (PPD) test, T-SPOT.TB and radiological examination indicated tuberculous meningitis. During treatment, the child developed hypertension, sinus tachycardia, tachypnoea, dystonia and high fever. These episodes improved after administration of propranolol, artane and clonazepam. Paroxysmal sympathetic hyperactivity is a rare manifestation of tuberculous meningitis. Early detection is very important as it can avoid diagnostic errors and overtreatment.

Morphine: An Effective Abortive Therapy for Pediatric Paroxysmal Sympathetic Hyperactivity After Hypoxic Brain Injury

Paroxysmal sympathetic hyperactivity (PSH) is a life-threatening condition characterized by hyperadrenergic activity and autonomic dysfunction. Also termed autonomic storms, PSH can occur after a variety of cerebral insults, most commonly traumatic brain injury. Limited pediatric literature is available, especially in patients with brain injury from hypoxia. No consensus exists for the terminology, diagnostic criteria, or treatment algorithm for PSH. Thus, the optimal management, including medication selection and dosing, remains unclear. We present the detailed treatment of a 9-year-old, African American male with hypoxic brain injury after pulseless arrest following status asthmaticus, who subsequently developed PSH. The patient began to experience episodes of tachycardia, hypertension, tachypnea, diaphoresis, rigidity, and dystonic posturing on hospital day 5. After ruling out other potential causes, a diagnosis of PSH was made. Episodes of PSH failed to respond to lorazepam or labetalol but were aborted successfully with morphine. Management of PSH after hypoxic brain injury required medications for acute treatment as well as for prevention of PSH. Morphine was found to be highly effective and safe for aborting the autonomic crises. Other agents more commonly described in the literature did not result in an adequate response and were associated with significant adverse effects. A combination of clonazepam, baclofen, and either propranolol or clonidine aided in reducing the frequency of episodes of PSH. We suggest using morphine for aborting severe episodes of PSH that do not respond to antihypertensive agents or benzodiazepines.

Treatment Progress of Paroxysmal Sympathetic Hyperactivity after Acquired Brain Injury

Paroxysmal sympathetic hyperactivity (PSH) is a common complication of various acquired brain injuries such as traumatic brain injury, subarachnoid hemorrhage, anoxic brain injury, intracerebral hemorrhage, and others. It is manifested by tachycardia, hypertension, tachypnea, diaphoresis, and dystonic posturing. The development of PSH can prolong hospitalization and lead to secondary brain injury and even death. Despite the awareness of the serious clinical impact, there is no consensus on diagnostic criteria. Thus, misdiagnosis and delayed recognition is very common. Most of the current treatment programs come from case reports and small case series; there are very few large-scale randomized controlled trials. Generally accepted medications are opioids, β-blockers and gabapentin (usually used in combination). However, the efficacy of these drugs has not been systematically assessed. The purpose of this review is to determine the treatment strategies and drugs commonly used for PSH at the overall level.

Hyperbaric oxygen treatment in autism spectrum disorders

Traditionally, hyperbaric oxygen treatment (HBOT) is indicated in several clinical disorders include decompression sickness, healing of problem wounds and arterial gas embolism. However, some investigators have used HBOT to treat individuals with autism spectrum disorders (ASD). A number of individuals with ASD possess certain physiological abnormalities that HBOT might ameliorate, including cerebral hypoperfusion, inflammation, mitochondrial dysfunction and oxidative stress. Studies of children with ASD have found positive changes in physiology and/or behavior from HBOT. For example, several studies have reported that HBOT improved cerebral perfusion, decreased markers of inflammation and did not worsen oxidative stress markers in children with ASD. Most studies of HBOT in children with ASD examined changes in behaviors and reported improvements in several behavioral domains although many of these studies were not controlled. Although the two trials employing a control group reported conflicting results, a recent systematic review noted several important distinctions between these trials. In the reviewed studies, HBOT had minimal adverse effects and was well tolerated. Studies which used a higher frequency of HBOT sessions (e.g., 10 sessions per week as opposed to 5 sessions per week) generally reported more significant improvements. Many of the studies had limitations which may have contributed to inconsistent findings across studies, including the use of many different standardized and non-standardized instruments, making it difficult to directly compare the results of studies or to know if there are specific areas of behavior in which HBOT is most effective. The variability in results between studies could also have been due to certain subgroups of children with ASD responding differently to HBOT. Most of the reviewed studies relied on changes in behavioral measurements, which may lag behind physiological changes. Additional studies enrolling children with ASD who have certain physiological abnormalities (such as inflammation, cerebral hypoperfusion, and mitochondrial dysfunction) and which measure changes in these physiological parameters would be helpful in further defining the effects of HBOT in ASD.

Hyperbaric oxygen therapy for traumatic brain injury: still an enigma

With their article on the use of HBOT for post TBI dysautonomia, Lv and colleagues discuss a novel use for this form of treatment. Although HBOT has been a part of our TBI treatment armamentarium for many years, its use remains a very controversial issue. In this commentary, the science and research studies behind HBOT for TBI are reviewed, hopefully leaving the reader with an adequate knowledge base to answer a patient or family's inquiries as to the usefulness of HBOT for TBI.