Incidence of paroxysmal sympathetic hyperactivity following traumatic brain injury using assessment tools

Paroxysmal sympathetic hyperexcitability after brain injury: A clinical analysis of case series

BACKGROUND

Paroxysmal sympathetic hyperexcitability (PSH) is a group of complex syndromes with various etiologies. Previous studies were limited to the description of traumatic brain injury (TBI), and the description of PSH after other types of brain injury was rare. We explored the clinical features, treatment, and prognosis of PSH after various types of brain injuries.

METHODS

Patients admitted to the neurosurgery intensive care unit with PSH after brain injury from July 2019 to December 2022 were included. Demographic data, clinical manifestations, drug therapy, and disease prognosis were retrospectively collected and analyzed.

RESULTS

Fifteen male and 9 female patients with PSH after brain injury were selected. TBI was most likely to cause PSH (66.7%), followed by spontaneous intracerebral hemorrhage (25%). Glasgow coma scale scores of 19 patients (79.2%) were lower than 8 and 14 patients (58.3%) underwent tracheotomy. Electroencephalogram monitoring was performed in 12 individuals, none of which showed epileptic waves. Clinical symptom scale showed mild symptoms in 17 cases (70.8%). Almost all patients were administered a combination of drugs. After follow-up, most patients had a poor prognosis and 2 (8.3%) died after discharge.

CONCLUSION

The etiology of PSH is complex. TBI may be the most common cause of PSH. Non-TBI may also be an important cause of PSH. Therefore, early identification, prevention and diagnosis are helpful for determining the prognosis and outcome of the disease.

Decreased levels of hydrogen sulfide in the hypothalamic paraventricular nucleus contribute to sympathetic hyperactivity induced by cerebral infarction

Paroxysmal sympathetic hyperactivity (PSH) is a common clinical feature secondary to ischemic stroke (IS), but its mechanism is poorly understood. We aimed to investigate the role of H2S in the pathogenesis of PSH. IS patients were divided into malignant (MCI) and non-malignant cerebral infarction (NMCI) group. IS in rats was induced by the right middle cerebral artery occlusion (MCAO). H2S donor (NaHS) or inhibitor (aminooxy-acetic acid, AOAA) were microinjected into the hypothalamic paraventricular nucleus (PVN). Compared with the NMCI group, patients in the MCI group showed PSH, including tachycardia, hypertension, and more plasma norepinephrine (NE) that was positively correlated with levels of creatine kinase, glutamate transaminase, and creatinine respectively. The 1-year survival rate of patients with high plasma NE levels was lower. The hypothalamus of rats with MCAO showed increased activity, especially in the PVN region. The levels of H2S in PVN of the rats with MCAO were reduced, while the blood pressure and renal sympathetic discharge were increased, which could be ameliorated by NaHS and exacerbated by AOAA. NaHS completely reduced the disulfide bond of NMDAR1 in PC12 cells. The inhibition of NMDAR by MK-801 microinjected in PVN of rats with MCAO also could lower blood pressure and renal sympathetic discharge. In conclusion, PSH may be associated with disease progression and survival in patients with IS. Decreased levels of H2S in PVN were involved in regulating sympathetic efferent activity after cerebral infarction. Our results might provide a new strategy and target for the prevention and treatment of PSH.

Paroxysmal Sympathetic Hyperactivity After Acquired Brain Injury: An Integrative Literature Review

BACKGROUND

Paroxysmal sympathetic hyperactivity may occur in patients with acute brain injury and is associated with physical disability, poor clinical outcomes, prolonged hospitalization, and higher health care costs.

OBJECTIVE

To comprehensively review current literature and provide information about paroxysmal sympathetic hyperactivity for nurses.

METHODS

An integrative literature review was conducted according to Whittemore and Knafl's method. The search was conducted from October 2020 through January 2021. The main targets of the literature search were definition, incidence rate, causes, clinical characteristics, pathophysiology, diagnosis, and treatment of paroxysmal sympathetic hyperactivity in pediatric and adult patients. The results were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

The most characteristic clinical features of paroxysmal sympathetic hyperactivity are hypertension, tachycardia, tachypnea, hyperthermia, diaphoresis, and abnormal motor posturing. Reported incidence rates of paroxysmal sympathetic hyperactivity in patients with brain injury range from 8% to 33%. Various diagnostic criteria have been proposed; most are based on clinical symptoms. Ruling out other causes of the signs and symptoms of paroxysmal sympathetic hyperactivity is important because the signs and symptoms are nonspecific. The major goals of paroxysmal sympathetic hyperactivity management are avoidance of stimuli that may trigger a paroxysmal episode, inhibition of sympathetic overactivity, and prevention of damage to other organs.

CONCLUSIONS

Critical care nurses should be aware of the signs and symptoms of paroxysmal sympathetic hyperactivity in patients with acute brain injury. Early identification is important to ensure timely treatment for patients with paroxysmal sympathetic hyperactivity.

Clinical characteristics and prognosis of paroxysmal sympathetic hyperactivity in patients with severe nontraumatic brain injury

OBJECTIVE

This prospective study investigated and analyzed the clinical characteristics and prognosis of paroxysmal sympathetic hyperactivity (PSH) in patients with severe nontraumatic brain injury.

METHODS

Patients presenting with severe nontraumatic brain injury with PSH from July 2018 to June 2019 were enrolled. A PSH assessment measure ≥ 8 points was used as the criterion for PSH. Clinical data, indicators related to PSH, treatment effects and the prognosis were prospectively collected and analyzed.

RESULTS

A total of 220 patients with severe nontraumatic brain injury were analyzed, and PSH occurred in 8 patients (3.6%).     The primary neurological diseases included acute cerebral infarction, anti-N-methyl-D-aspartate receptor encephalitis, hypoxic encephalopathy and acute disseminated encephalitis. The Glasgow Coma Scale score was lower than 8 in the 8 patients with PSH. Seven of these eight patients had a Glasgow outcome scale (GOS) score of 3 or less than 3, and one patient had a GOS of 5 after 6 months. The medicines that effectively controlled PSH included dexmedetomidine, clonazepam, midazolam and diazepam.

CONCLUSIONS

Although the incidence was lower for nontraumatic brain injury complicated with PSH than for traumatic brain injury, patients with PSH had a more severe disease state and poorer prognoses. Dexmedetomidine might effectively control PSH.

Paroxysmal Sympathetic Hyperactivity in Neurocritical Children: A Pilot Study

Background

Paroxysmal sympathetic hyperactivity (PSH) is characterized by the abnormal excessive sympathetic response to acute cerebral insult. There is a paucity of data about this condition in children. This study was planned to analyze the incidence of PSH among children requiring neurocritical care and its association with the outcome.

Materials and methods

The study was conducted in the pediatric intensive care unit (PICU) of a tertiary care hospital over a period of 10 months. Children of age 1 month to 12 years admitted with neurocritical illnesses were included. Children who were declared brain dead after initial resuscitation were excluded from the study. The criterion laid by Moeller et al. was used for the diagnosis for PSH.

Results

During the study period, 54 children requiring neurocritical care were included in the study. The incidence of PSH was 5/54 (9.2%). Additionally, 30 (55.5%) children had less than four criteria for PSH and were termed as "incomplete PSH." Children with all four criteria for PSH had a significantly longer duration of mechanical ventilation, PICU stay, and higher PRISM III scores. Children with less than four criteria for PSH also had a longer duration of mechanical ventilation and stay. However, there was no significant difference in mortality.

Conclusion

Paroxysmal sympathetic hyperactivity is common in children with neurological illnesses admitted to the PICU and is associated with longer mechanical ventilation and stay in PICU. They also had higher illness severity scores. Timely diagnosis of the condition and appropriate management is required to improve the outcome of these children.

How to cite this article

Agrwal S, Pallavi, Jhamb U, Saxena R. Paroxysmal Sympathetic Hyperactivity in Neurocritical Children: A Pilot Study. Indian J Crit Care Med 2022;26(11):1204-1209.

Paroxysmal Sympathetic Hyperactivity in Adult Patients with Brain Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) is a syndrome of excessive sympathetic activity, mainly occurring in severe traumatic brain injury. However, few studies have reported the frequency of PSH and its related risk factors in adult patients with brain injury.

METHODS

We performed this systematic review and meta-analysis to estimate the combined incidence of PSH and the associated risk factors in adult patients with brain injury. This study was registered with the PROSPERO international prospective register of systematic reviews (https://www.crd.york. ac.uk/PROSPERO/Identifier: CRD 42021260493), and a systematic search was conducted of the scientific databases Embase, PubMed, Web of Science, Cochrane Library, and Google Scholar. All identified observational studies regarding the incidence and risk factors of PSH in adult patients with brain injury were included. Two authors extracted data independently; data were analyzed by STATA version 16.

RESULTS

The search yielded 9 studies involving 1643 adult patients. PSH was detected in 438 patients. The combined incidence of PSH in adult patients with brain injury was 27.4% (95% confidence interval [CI], 0.190-0.358). The risk factors include patients' age (SMD = -0.592; I² = 77.5%; 95% CI, -1.027 to -0.156; P = 0.008), traffic accident (odds ratio [OR], 1.783; I² =18.0%; 95% CI, 1.128-2.820; P = 0.013), admission Glasgow Coma Scale score (SMD = -1.097; I² =28.3%; 95% CI, -1.500 to -0.693; P = 0.000), hydrocephalus (OR, 3.936; I² =67.9%; 95% CI, 1.144-13.540; P = 0.030), and diffuse axonal injury (OR, 4.747; I² =71.1%; 95% CI, 1.221-18.463; P = 0.025) and were significantly associated with the presence of PSH after brain injury.

CONCLUSIONS

PSH occurs in nearly a quarter of adult patients with brain injury. Patient's age, traffic accident, admission Glasgow Coma Scale score, hydrocephalus, and diffuse axonal injury were risk factors for PSH in adult patients with brain injury. These findings may contribute to novel strategies for early diagnosis and interventions that aid in the rehabilitation of patients with brain injury.

Trans-cranial Doppler Flow Characteristics of a Child with Paroxysmal Sympathetic Hyper-activity: A Preliminary Report

Background

Paroxysmal sympathetic hyper-activity (PSH) is a syndrome characterized by excessive activity of the sympathetic nervous system. The cerebrovascular flow dynamics during the episodes of paroxysmal hyper-activity has also not been clearly examined in the literature.

Case History

A 12-year-old boy with operated exophytic brain stem pilocytic astrocytoma was diagnosed with paroxysmal sympathetic hyper-activity. The trans-cranial Doppler flow characteristics of the bilateral middle cerebral artery and anterior cerebral artery are described in this report.

Conclusion

The diagnosis of PSH requires an index of suspicion on the part of the clinician. The episodes of sympathetic hyper-activity are associated with significant changes in physiologic parameters in the patients including changes in cerebrovascular flow dynamics.

Characteristics and Outcomes of Paroxysmal Sympathetic Hyperactivity in Anti-NMDAR Encephalitis

Background

To explore the clinical characteristics and prognosis of autonomic dysfunction and paroxysmal sympathetic hyperactivity (PSH), and evaluate the efficacy of drugs used to suppress PSH episode in anti-NMDAR encephalitis patients.

Methods

Patients who met the diagnostic criteria of anti-NMDAR encephalitis were enrolled from January 2012 to August 2018 and followed up for 2 years. PSH was diagnosed according to the PSH-Assessment Measure. The demographics data, clinical features, auxiliary tests results, treatments, and outcomes were prospective collected and analyzed.

Results

A total of 132 anti-NMDAR encephalitis patients were enrolled, of which 27.3% and 9.1% experienced autonomic dysfunction and probable PSH respectively. Cardiac autonomic dysfunction was the most common subtype (77.8%). Patients with a higher incidence of ovarian teratoma, mechanical ventilation, neurological intensive care unit admission, and elevated glucose and NMDAR antibody titer in the CSF were more likely to exhibit autonomic dysfunction or PSH. Episodes of PSH can be suppressed by monotherapy in patients without prior sedative drug use with an efficacy of 90%. No significant difference was observed between the prognosis of patients with or without autonomic dysfunction, or between the PSH versus non-PSH groups after 6 months and even during long-term follow-up. However, patients with cardiac autonomic dysfunction had poor prognosis at 6 months.

Conclusion

PSH is a common clinical condition in patients with anti-NMDAR encephalitis, especially in severe cases, and can be effectively managed by several drug monotherapies. Despite necessitating longer hospital stay, autonomic dysfunction or PSH do not seem to compromise the neurological recovery of patients.

Leveraging Continuous Vital Sign Measurements for Real-Time Assessment of Autonomic Nervous System Dysfunction After Brain Injury: A Narrative Review of Current and Future Applications

Subtle and profound changes in autonomic nervous system (ANS) function affecting sympathetic and parasympathetic homeostasis occur as a result of critical illness. Changes in ANS function are particularly salient in neurocritical illness, when direct structural and functional perturbations to autonomic network pathways occur and may herald impending clinical deterioration or intervenable evolving mechanisms of secondary injury. Sympathetic and parasympathetic balance can be measured quantitatively at the bedside using multiple methods, most readily by extracting data from electrocardiographic or photoplethysmography waveforms. Work from our group and others has demonstrated that data-analytic techniques can identify quantitative physiologic changes that precede clinical detection of meaningful events, and therefore may provide an important window for time-sensitive therapies. Here, we review data-analytic approaches to measuring ANS dysfunction from routine bedside physiologic data streams and integrating this data into multimodal machine learning-based model development to better understand phenotypical expression of pathophysiologic mechanisms and perhaps even serve as early detection signals. Attention will be given to examples from our work in acute traumatic brain injury on detection and monitoring of paroxysmal sympathetic hyperactivity and prediction of neurologic deterioration, and in large hemispheric infarction on prediction of malignant cerebral edema. We also discuss future clinical applications and data-analytic challenges and future directions.

Paroxysmal sympathetic hyperactivity during traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of disability, morbidity, and mortality worldwide. Some of the more common etiologies of TBI include closed head injury, penetrating head injury, or an explosive blast head injury. Neuronal damage in TBI is related to both primary injury (caused by mechanical forces), and secondary injury (caused by the subsequent tissue and cellular damages). Recently, it has been well established that Paroxysmal Sympathetic Hyperactivity (PSH), also known as "Sympathetic Storm", is one of the main causes of secondary neuronal injury in TBI patients. The clinical manifestations of PSH include recurrent episodes of sympathetic hyperactivity characterized by tachycardia, systolic hypertension, hyperthermia, tachypnea with hyperpnea, and frank diaphoresis. Given the diverse manifestations of PSH and its notable impact on the outcome of TBI patients, we have comprehensively reviewed the current evidence and discussed the pathophysiology, clinical manifestations, time of onset and duration of PSH during TBI. This article reviews the different types of head injuries that most commonly lead to PSH, possible approaches to manage and minimize PSH complications in TBI and the current prognosis and outcomes of PSH in TBI patients.

Admission Features Associated With Paroxysmal Sympathetic Hyperactivity After Traumatic Brain Injury: A Case-Control Study

OBJECTIVES

Paroxysmal sympathetic hyperactivity occurs in a subset of critically ill traumatic brain injury patients and has been associated with worse outcomes after traumatic brain injury. The goal of this study was to identify admission risk factors for the development of paroxysmal sympathetic hyperactivity in traumatic brain injury patients.

DESIGN

Retrospective case-control study of age- and Glasgow Coma Scale-matched traumatic brain injury patients.

SETTING

Neurotrauma ICU at the R. Adams Cowley Shock Trauma Center of the University of Maryland Medical System, January 2016 to July 2018.

PATIENTS

Critically ill adult traumatic brain injury patients who underwent inpatient monitoring for at least 14 days were included. Cases were identified based on treatment for paroxysmal sympathetic hyperactivity with institutional first-line therapies and were confirmed by retrospective tabulation of established paroxysmal sympathetic hyperactivity diagnostic and severity criteria. Cases were matched 1:1 by age and Glasgow Coma Scale to nonparoxysmal sympathetic hyperactivity traumatic brain injury controls, yielding 77 patients in each group.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Admission characteristics independently predictive of paroxysmal sympathetic hyperactivity included male sex, higher admission systolic blood pressure, and initial CT evidence of diffuse axonal injury, intraventricular hemorrhage/subarachnoid hemorrhage, complete cisternal effacement, and absence of contusion. Paroxysmal sympathetic hyperactivity cases demonstrated significantly worse neurologic outcomes upon hospital discharge despite being matched for injury severity at admission.

CONCLUSIONS

Several anatomical, epidemiologic, and physiologic risk factors for clinically relevant paroxysmal sympathetic hyperactivity can be identified on ICU admission. These features help characterize paroxysmal sympathetic hyperactivity as a clinical-pathophysiologic phenotype associated with worse outcomes after traumatic brain injury.

Paroxysmal Sympathetic Hyperactivity in Severe Anti-N-Methyl-d-Aspartate Receptor Encephalitis: A Single Center Retrospective Observational Study

Background

Paroxysmal sympathetic hyperactivity (PSH) is a disorder with excessive sympathetic activity commonly recognized in patients with acquired brain injury. Autonomic instability is frequent in anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE). However, PSH in anti-NMDARE has gained little attention.

Methods

We retrospectively reviewed 24 patients diagnosed with severe anti-NMDARE in the neuro-intensive care unit (NICU) between 2014 and 2019. Patients were assessed with the PSH assessment measure (PSH-AM) scale, and categorized into “PSH+” group and “PSH-” group. The clinical characteristics, hospital mortality, and functional outcome by modified Rankin Scale (mRS) score at six months after discharge were compared between the two groups. Among patients with PSH+, the clinical features and pharmacotherapy of PSH were summarized and compared.

Results

Twenty-four patients were included in the study. Twelve of them (50%) were categorized as PSH+ based on PSH-AM scores. There were no significant differences in the demographic characteristic, GCS scores upon admission, incidence of status epilepticus, teratoma occurrence, hospital mortality, and 6-month mRS between PSH+ and PSH- groups. Patients with PSH+ had increased length of NICU stay, hospital stay and duration of mechanical ventilation. The most prominent clinical features of PSH in severe anti-NMDARE were tachycardia and hyperthermia, while posturing was the relatively mildest clinical feature. Propranolol and clonazepam were more commonly used than gabapentin in pharmacotherapy of PSH in severe anti-NMDARE.

Conclusions

The incidence of PSH in severe anti-NMDARE patients was as high as 50%. Patients with PSH demonstrated prolonged NICU stay, hospital stay and increased duration of mechanical ventilation, while no effect on hospital mortality and functional outcome. Clinicians should be aware of the distinctive characteristics and treatment options of PSH in severe anti-NMDARE.

Effectiveness of Pharmacological Agents and Validation of Diagnostic Scales for the Management of Paroxysmal Sympathetic Hyperactivity in Hispanics

The identification and treatment of paroxysmal sympathetic hyperactivity (PSH) still present a significant challenge. We assessed the efficacy of pharmacological agents in treating PSH symptoms and the validity of the diagnostic scales in a cohort of Hispanic patients. A retrospective chart review of cases from a single hospital was conducted in 464 records. Exclusion criteria included underlying conditions such as severe infection. Only nine patients remained in the cohort after examining their clinical records, corresponding to the following diagnoses: traumatic brain injury, subdural hemorrhage, anoxic or ischemic encephalopathy, pneumocephalus, and cerebral palsy. Using the PSH likelihood scale, six of the nine patients were identified with a score of 17 or higher, corresponding to a "probable" PSH, and three patients obtained a score between 8 and 16, corresponding to a "possible" PSH diagnosis. The top three classes of medications used were beta-blockers, antipyretics, and opioids. Benzodiazepines and neuromodulators were also frequently used in patients with trauma, but not in the ones with non-traumatic injuries. Interestingly, 75% of the patients have prescribed levothyroxine as a home medication after the PSH presentation. Medication administration did not follow a specific pattern, suggesting high variability in the management of PSH within our setting, requiring further research. Our results suggest that the pituitary axis might be involved in the progression of PSH. Establishing a specific medical code (e.g., ICD-10) describing PSH as a single entity is essential for appropriate identification and management.

Autonomic Hyperactivity

PURPOSE OF REVIEW

Autonomic hyperactivity is a relatively common consequence of severe acute brain injury and can also be seen with spinal cord and peripheral nerve disorders. This article reviews basic pathophysiologic concepts regarding autonomic hyperactivity, its various forms of clinical presentation, and practical management considerations.

RECENT FINDINGS

Paroxysmal sympathetic hyperactivity is most common after traumatic brain injury but can also occur after other forms of severe acute diffuse or multifocal brain injury. Formal criteria for the diagnosis and severity grading of paroxysmal sympathetic hyperactivity have now been proposed. A growing body of literature is beginning to elucidate the mechanisms underlying this disorder, but treatment remains based on observational data. Our mechanistic understanding of other distinct forms of autonomic hyperactivity, such as autonomic dysreflexia after traumatic spinal cord injury and dysautonomia after Guillain-Barré syndrome, remains rudimentary, yet clinical experience shows that their appropriate management can minimize the risk of serious complications.

SUMMARY

Syndromes of autonomic hyperactivity can result from injury at all levels of the neuraxis. Much more research is needed to refine our understanding of these disorders and guide optimal management decisions.

Paroxysmal Sympathetic Hyperactivity

Paroxysmal sympathetic hyperactivity (PSH) is a relatively common, but often unrecognized, complication of acute diffuse or multifocal brain diseases, most frequently encountered in young comatose patients with severe traumatic brain injury. It is presumed to be caused by loss of cortical inhibitory modulation of diencephalic and brain stem centers and possible additional maladaptive changes in the spinal cord that combine to produce exaggerated sympathetic responses to stimulation. The syndrome consists of repeated sudden episodes of tachycardia, tachypnea, hypertension, sweating, and sometimes fever and dystonic posturing. The diagnosis is clinical. Treatment includes reducing any external stimulation that can trigger the episodes, and starting abortive (e.g., intravenous morphine) and preventive medications (e.g., gabapentin, propranolol, clonidine). Prompt and adequate treatment of PSH may reduce the likelihood of secondary complications, such as dehydration, weight loss and malnutrition, and muscle contractures.

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.