Paroxysmal Sympathetic Hyperactivity After Acute Brain Injury

[Postoperative management following decompressive hemicraniectomy for malignant middle cerebral artery infarction-A German nationwide survey study]

BACKGROUND

Malignant middle cerebral artery infarction is a potentially life-threatening disease. Decompressive hemicraniectomy constitutes an evidence-based treatment practice, especially in patients under 60 years of age; however, recommendations with respect to postoperative management and particularly duration of postoperative sedation lack standardization.

OBJECTIVE

This survey study aimed to analyze the current situation of patients with malignant middle cerebral artery infarction following hemicraniectomy in the neurointensive care setting.

MATERIAL AND METHODS

From 20 September 2021 to 31 October 2021, 43 members of the initiative of German neurointensive trial engagement (IGNITE) network were invited to participate in a standardized anonymous online survey. Descriptive data analysis was performed.

RESULTS

Out of 43 centers 29 (67.4%) participated in the survey, including 24 university hospitals. Of the hospitals 21 have their own neurological intensive care unit. While 23.1% favored a standardized approach regarding postoperative sedation, the majority utilized individual criteria (e.g., intracranial pressure increase, weaning parameters, complications) to assess the need and duration. The timing of targeted extubation varied widely between hospitals (≤ 24 h 19.2%, ≤ 3 days in 30.8%, ≤ 5 days in 19.2%, > 5 days in 15.4%). Early tracheotomy (≤ 7 days) is performed in 19.2% and 80.8% of the centers aim for tracheotomy within 14 days. Hyperosmolar treatment is used on a regular basis in 53.9% and 22 centers (84.6%) agreed to participate in a clinical trial addressing the duration of postoperative sedation and ventilation.

CONCLUSION

The results of this nationwide survey among neurointensive care units in Germany reflect a remarkable heterogeneity in the treatment practices of patients with malignant middle cerebral artery infarction undergoing hemicraniectomy, especially with respect to the duration of postoperative sedation and ventilation. A randomized trial in this matter seems warranted.

Beta1-receptor blockade attenuates atherosclerosis progression following traumatic brain injury in apolipoprotein E deficient mice

Traumatic brain injury (TBI) is associated with cardiovascular mortality in humans. Enhanced sympathetic activity following TBI may contribute to accelerated atherosclerosis. The effect of beta1-adrenergic receptor blockade on atherosclerosis progression induced by TBI was studied in apolipoprotein E deficient mice. Mice were treated with metoprolol or vehicle following TBI or sham operation. Mice treated with metoprolol experienced a reduced heart rate with no difference in blood pressure. Six weeks following TBI, mice were sacrificed for analysis of atherosclerosis. Total surface area and lesion thickness, analyzed at the level of the aortic valve, was found to be increased in mice receiving TBI with vehicle treatment but this effect was ameliorated in TBI mice receiving metoprolol. No effect of metoprolol on atherosclerosis was observed in mice receiving only sham operation. In conclusion, accelerated atherosclerosis following TBI is reduced with beta-adrenergic receptor antagonism. Beta blockers may be useful to reduce vascular risk associated with TBI.

Weathering the storm: a single-institution experience with paroxysmal sympathetic hyperactivity after brain tumor resection in pediatric patients

OBJECTIVE

Paroxysmal sympathetic hyperactivity (PSH) is a complication of severe traumatic or hypoxic brain injury characterized by transient episodes of tachycardia, tachypnea, hypertension, hyperthermia, diaphoresis, and/or dystonic posturing. Posttraumatic "sympathetic storms" are associated with poor outcomes. PSH rarely occurs after brain tumor resection in pediatric patients; only 4 cases have been published since 1929. Thus, the authors sought to report their experience with postcraniotomy PSH in pediatric brain tumor patients.

METHODS

A retrospective study of patients younger than 18 years of age who underwent craniotomy for brain tumor resection at a single center by a single surgeon over a 7-year period was performed. A clinical diagnosis of postoperative PSH was recorded. Recorded outcomes included the interval between surgery and initiation of cytotoxic therapy, need for long-term CSF diversion, length of hospital stay, and survival.

RESULTS

Of the 150 patients who were included for analysis, 4 patients were diagnosed with postoperative PSH for an overall occurrence of 2.7%. PSH patients were younger than non-PSH patients (1.8 ± 0.4 years vs 9.2 ± 5.3 years, p = 0.010) and tended to have intraventricular tumors close to the thalamus, basal ganglia, and/or brainstem. PSH patients experienced longer hospital admissions (44.3 ± 23.4 days vs 6.8 ± 9.4 days, p = 0.001), a shorter interval between surgery and initiation of cytotoxic cancer-directed therapy (14.3 ± 8.0 days vs 90.7 days ± 232.9 days, p = 0.011), and increased need for long-term CSF diversion compared with non-PSH patients (75% vs 25%, p = 0.005). At the last follow-up, 50% of PSH patients had died compared with 13% of non-PSH patients (p = 0.094).

CONCLUSIONS

PSH is a rare postoperative complication that may affect young children with periventricular tumors and is associated with poorer clinical outcomes. Increasing awareness of this condition is vital to improving patient outcomes.

Comparison of Midazolam and Propofol Infusion to Suppress Stress Response in Patients With Severe TBII: A Prospective, Randomized Controlled Trial

Objective

The stress response following traumatic brain injury (TBI) is a preventable cause of secondary brain injury. This can be prevented using sedation in the intensive care unit (ICU). To date, the choice of sedative agent for preventing stress response is not well-studied in literature.

Methods

This prospective randomized controlled trial included 60 patients with severe TBI admitted to ICU. The patients were randomized into 2 study groups according to the choice of sedation: propofol (group I) and midazolam infusion (group II). The serum cortisol was measured as the primary outcome at admission to ICU and 48 hours following sedation infusion. The baseline Glasgow coma scale, hemodynamic, optic nerve sheath diameter (ONSD), and computed tomography scan findings were noted at admission. Glasgow outcome scale (GOS) was measured as a neurological outcome at discharge from ICU.

Results

There was a statistically significant reduction in serum cortisol level in both the study groups (Δ cortisol, p-value=134.91 (50.5,208.2), 0.00 and 118.8 (42.6,160.4), 0.00, in group I and II, respectively). Serum cortisol levels were comparable among both groups at baseline and 48 hours. Similarly, there was a statistically significant difference in ONSD in both groups, but there was no difference in ONSD value between the groups at 48 hours. The GOS was also similar in both groups at discharge from ICU.

Conclusion

The study demonstrated a similar reduction in serum cortisol levels following 48 hours of propofol or midazolam infusion in patients with severe TBI.

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 syndrome in tuberculous meningitis with paradoxical reaction

Introduction and importance

Paroxysmal sympathetic hyperactivity syndrome is frequently reported in traumatic brain injury. However, it may occur in non-traumatic brain injury, such as tuberculous meningitis with hydrocephalus.

Case presentation

We reported a 38-year-old male who presented with acute decrease of consciousness and hemiparesis that was developed during antitubercular drugs therapy. CT Scan showed hydrocephalus and granuloma lesion. Emergency ventriculoperitoneal shunting were performed. During treatment, the patient developed paroxysmal sympathetic syndrome during treatment that was controlled based on symptom elimination and prevention.

Clinical discussion

Brain tuberculosis remains a difficult problem for clinicians. Even when antitubercular drugs are administered according to protocol, paradoxical reactions can occur. If hydrocephalus develops, ventriculoperitoneal shunting is one of the options for lowering intracranial pressure. Paroxysmal sympathetic hyperactivity may occur in brain tuberculosis and should be detected as soon as possible to avoid serious morbidity.

Conclusion

Paroxysmal sympathetic hyperactivity may be developed in brain tuberculosis. Early identification and treatment are mandatory.

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Paroxysmal sympathetic hyperactivity (PSH) syndrome may be observed in non-traumatic brain injury

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Treatment of PSH was based on symptoms elimination and symptoms prevention.

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Paradoxical reaction in tuberculosis, characterized by the appearance of new clinical symptoms during antitubercular drug therapy

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Ventriculoperitoneal shunting to reduce intracranial pressure in hydrocephalus following meningitis tuberculosis

Systemic immune responses after ischemic stroke: From the center to the periphery

Ischemic stroke is a leading cause of disability and death. It imposes a heavy economic burden on individuals, families and society. The mortality rate of ischemic stroke has decreased with the help of thrombolytic drug therapy and intravascular intervention. However, the nerve damage caused by ischemia-reperfusion is long-lasting and followed by multiple organ dysfunction. In this process, the immune responses manifested by systemic inflammatory responses play an important role. It begins with neuroinflammation following ischemic stroke. The large number of inflammatory cells released after activation of immune cells in the lesion area, along with the deactivated neuroendocrine and autonomic nervous systems, link the center with the periphery. With the activation of systemic immunity and the emergence of immunosuppression, peripheral organs become the second “battlefield” of the immune response after ischemic stroke and gradually become dysfunctional and lead to an adverse prognosis. The purpose of this review was to describe the systemic immune responses after ischemic stroke. We hope to provide new ideas for future research and clinical treatments to improve patient outcomes and quality of life.

SAM, a cystathionine beta-synthase activator, promotes hydrogen sulfide to promote neural repair resulting from massive cerebral infarction induced by middle cerebral artery occlusion

Neurologic deterioration after massive cerebral infarct should be identified at an early stage for medical and surgical treatments. We investigated the effect of hydrogen sulfide on the excitotoxity of PC12 cells exposed to oxygen-glucose deprivation (OGD) and its effect on the apoptosis of brain tissues in rats with middle cerebral artery occlusion (MCAO). Rats with MCAO were treated with SAM, a cystathionine beta-synthase (CBS) activator, or AOAA, a CBS inhibitor. Hydrogen sulfide content in the brain tissues of infarcted patients or rats with MCAO was decreased, whereas glutamate (GLU) content was increased. In addition, SAM reduced reactive oxygen species content, lactate dehydrogenase release, and apoptosis levels in the brain tissues of rats with MCAO. The PC12 cells that were exposed to OGD were also treated with 20 mM GLU and later treated with SAM or AOAA. In PC12 cells, SAM reduced the apoptosis caused by GLU after OGD. The protective effects of hydrogen sulfide was elicited through the sulfur-sulfhydrylation modification of NMDAR and the induction of ERK/MAPK signaling. Our results showed that hydrogen sulfide exerts a protective effect on the PC12 cells and the rats with MCAO, which might represent a possible therapeutic agent against massive cerebral infarct.

Spasticity management and resolution of paroxysmal sympathetic hyperactivity in the acute care setting: a case series

OBJECTIVE

The aim is to highlight three cases of focal spasticity and/or dystonia as potential noxious triggers and treatment targets of Paroxysmal Sympathetic Hyperactivity (PSH).

METHODS

We review the literature, explore pathophysiology, and review treatment options. We discuss the clinical course and management of three unique patients who presented to a teaching hospital with severe traumatic brain injury (TBI) complicated by PSH managed by a physiatry consult team.

RESULTS

Three patients, ranging in age from 8 months to 27 years, were admitted with severe TBI complicated by PSH refractory to pharmacologic management. All three patients, however, had resolution of PSH within 24-72 hours of focal spasticity treatments (i.e. casting and botulinum toxin injections).

CONCLUSION

PSH is a constellation of physiologic findings and physical symptoms that is incompletely understood. Management is based on addressing predominant symptom features and physiologic responses. In certain cases, ongoing spasticity and/or dystonia may serve as noxious stimuli for persistence of PSH in moderate to severe brain injury. As such, the focal treatment of spasticity and/or dystonia may be considered as a treatment target in the management of refractory PSH.

Inductive stimuli of the startle response and critical points of psychological treatment in a severe burn patient

Severe burn patients often have anxiety, depression, and stress-related disorders. The case we reported was very nervous and exhibited a long-term high-frequency startle response, which disrupted his sleep seriously and decreased treatment compliance. However, after psychological treatment, his startle response in the daytime and nervousness gradually improved, but the startle response at night remained unchanged. Furthermore, after his wife was given three sessions of psychological treatment to manage her fear of surgery, the startle response at night was significantly reduced. Herein, we summarize the inductive stimuli of the startle response and the critical points of psychological treatment in this case to provide the clinical experience for future research.

Paroxysmal sympathetic hyperactivity following acute diffuse brain swelling due to traumatic brain injury: a case report with good clinical outcome

Background

Paroxysmal sympathetic hyperactivity (PSH) may occur after acquired brain injury. The clinical presentation of PSH results from increased sympathetic overdrive, including transient paroxysms of tachycardia, hypertension, hyperventilation, hyperthermia, dystonic posturing, and excessive sweating. The exact pathophysiology of PSH, however, remains unclear, and no definitive treatment is available. Herein, the authors report a case of PSH in a male patient who experienced acute brain swelling after acquired head injury, for which a good clinical outcome was achieved due to multimodal treatment. The ensuing discussion also addresses the pathophysiology of PSH.

Case presentation

An 18-year-old man was transported to the authors’ hospital after experiencing a traumatic brain injury. On admission, computed tomography revealed cerebral herniation due to diffuse brain edema in the left parietal lobe. Emergency decompressive craniotomy and internal decompression were performed. After surgery, anti-edema therapy (glycerol and mannitol) was continued. Ten days postoperatively, PSH was diagnosed in accordance with the PSH assessment score (20 points). Vecuronium, fentanyl, morphine, propofol, dexmedetomidine, and a calcium channel blocker were administered; however, the drug effect was insufficient. Thirty-two days postsurgery, the patient gradually recovered from the adrenergic symptoms of PSH, and head computed tomography performed 32 days after surgery revealed improvement in diffuse brain edema. Ultimately, the patient fully recovered and lived independently at home.

Conclusions

Considering the pathophysiology of PSH, cerebral contusion, acute brain swelling, and secondary mechanisms of brain injury may trigger sympathetic nerve-enhancing regions and cause hyperexcitation of the sympathetic nervous system, resulting in PSH. The outcome of the present case demonstrates that PSH can be reversed if it is identified early and before it becomes irreversible, that is, post the development of hypoxic encephalopathy or widespread brain damage. Appropriate management, including decompression craniotomy for brain swelling and multidisciplinary treatment, leads to good clinical outcomes.

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.

Paroxysmal Sympathetic Hyperactivity in Moderate-to-Severe Traumatic Brain Injury and the Role of Beta-Blockers: A Scoping Review

Introduction

Most cases of paroxysmal sympathetic hyperactivity (PSH) result from traumatic brain injury (TBI). Little is known about its pathophysiology and treatment, and several neuroprotective drugs are used including beta-blockers. The aim of our study is to collate existing evidence of the role of beta-blockers in the treatment of PSH.

Methods

We searched MEDLINE, ResearchGate, and Google Scholar, for keywords related to PSH and the role of beta-blockers in moderate-to-severe TBI on September 23, 2020. Two authors blindly screened the articles found with Rayyan. Both resolved their conflicts by mutual consent. If no solution was found, a third author was consulted. Simple descriptive data analysis was performed and the results were presented both in a narrative and tabular form.

Results

Of the 19 items found, 10 met the criteria for inclusion. 50% were systematic reviews without meta-analysis, 40% were observational studies, and 10% were experimental studies. Propranolol was the main beta-blocker found in 80% of the studies and was the only molecule used in the treatment of paroxysmal sympathetic hyperactivity in 40% of the included studies. Only two studies evaluated and showed a significant association between beta-blockers and mortality rate (5.1% vs. 10.8%; P=0.03), (3% vs. 15%; P=0.002), respectively.

Conclusion

Propranolol is the beta-blocker that has been shown to be effective in reducing the length of stay and mortality rate in moderate-severe traumatic brain injury patients with PSH. However, further studies are needed to precisely define the terms and conditions of its use.

Incidence of Paroxysmal Sympathetic Hyperactivity after Traumatic Brain Injury in a Tertiary Care ICU: A Retrospective Cohort Study

Background Paroxysmal sympathetic hyperactivity (PSH) is an understudied complication of traumatic brain injury (TBI). PSH usually presents with transient rise in sympathetic outflow, leading to increased blood pressure, heart rate, temperature, respiratory rate, sweating, and posturing activity. We retrospectively analyzed the incidence of PSH in TBI using PSH-assessment measure (PSH-AM) scale.

Methods This single-center retrospective cohort study was conducted in traumatic head injury patients admitted in the intensive care unit from January 1, 2016 to December 31, 2019 in a tertiary care center. The data was collected from the hospital database after obtaining approval from the hospital ethics committee.

Results A total of 287 patients (18–65 years of age) were admitted to intensive care unit (ICU) with TBI out of which 227 patients were analyzed who had ICU stay for more than 14 days. PSH was diagnosed in 70 (30.8%) patients. Mean age of PSH positive patients was 40 ± 18 and 49 ± 11 years for PSH negative patients (p < 0.001). The age group between 40 and 50 years had a higher incidence of PSH. The age and Glasgow coma score (GCS) were significantly associated with the occurrence of PSH. The GCS score demonstrated good accuracy for predicting the occurrence of PSH with AUC 0.83, 95% CI of 0.775 to 0.886, and a p-value of 0.001.

Conclusion We observed that the incidence of PSH was 30.8% in the patients with TBI. Age and GCS were found to have a significant association for predicting the occurrence of PSH. The patients who developed PSH had a longer length of hospital stay in ICU.

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.

Diagnosis and Treatment of Paroxysmal Sympathetic Hyperactivity in Medical ICU, University of Gondar Hospital, Northwest Ethiopia: A Case Report

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) is a neurologic syndrome characterized by paroxysmal and simultaneous occurrence of hypertension, hyperpyrexia, tachycardia, tachypnea, diaphoresis and dystonic posturing due to surge in sympathetic outflow after acquired brain injuries. Diagnosis of PSH is made using the paroxysmal sympathetic hyperactivity-assessment measure (PSH-AM) score, which comprises "clinical features severity" (CFS) score and "diagnosis likelihood tool" (DLT) score.

CASE PRESENTATION

A 35-year-old woman diagnosed to have echo-proven chronic rheumatic heart disease for 25 years. Percutaneous balloon mitral valvotomy was done 6 weeks previously for severe mitral stenosis. Left atrial thrombus was detected after the procedure and anticoagulant (warfarin) was initiated. She presented with severe headache and repeated vomiting of 1 day duration on arrival to the hospital. She had frequent seizure attacks with subsequent loss of consciousness on third day of admission. Diagnosis of status epilepticus secondary to intracranial hemorrhage due to warfarin toxicity was made after CT-scan revealed acute subdural hematoma and ventricular bleeding. Then she was transferred to medical intensive care unit (ICU), intubated and put on mechanical ventilator. Anti-epileptic drugs, antibiotics, vitamin K and fresh frozen plasma were given. She developed paroxysms of hypertension, tachycardia, tachypnea, hyperpyrexia, diaphoresis and decerebrate posturing after 7 days of neurological insult. She had normal inter-ictal EEG tracing during cyclic autonomic surge. CFS score was 11 and DLT score was 10. In sum, PSH-AM score was 21, suggested "probable" diagnosis of PSH. Morphine, diazepam, propranolol and gabapentin were given in combination to treat PSH. Severity of autonomic storm started to improve on second week of ICU admission. On the third week of admission, her clinical condition deteriorated suddenly, she developed asystole and died of cardiac arrest despite cardiopulmonary resuscitation (CPR).

CONCLUSION

'Clinical scoring' was used used to diagnose PSH, since there was no any confirmatory test. Cocktail of drugs were required to treat catecholamine surge in PSH.

[HYpertension due to sympathetic hyperactivity after severe head injury]

We present the case of a 34-year-old patient with severe head trauma and severe brain involvement. The patient deteriorated progressively and required several reinterventions for bleeding and brain herniation. We were consulted by neurosurgery due to irregular blood pressure control despite treatment with calcium antagonists. The patient had associated diaphoresis, tachypnoea and tachycardia, together with persistent high-grade fever with no microbiological evidence. Laboratory tests showed normal kidney function, with no proteinuria and no signs of left ventricular hypertrophy to suggest previous arterial hypertension. This led us to consider sympathetic hyperactivity syndrome as a first possible diagnosis due to severe neurological damage. In line with this suspicion, antihypertensive therapy was initiated which included non-cardioselective beta-blockers, alpha-2 agonists, benzodiazepines and GABA receptor agonists. Thus, we were able to improve the labile blood pressure levels, which supports the diagnosis.

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.

Influence of paroxysmal sympathetic hyperactivity (PSH) on the functional outcome of neurological early rehabilitation patients: a case control study

Background

Paroxysmal Sympathetic Hyperactivity (PSH) is a frequently observed condition among critically ill patients on intensive care units. According to different studies, PSH is associated with worse recovery and increased mortality in acute-care facilities. In this monocentric, retrospective case-control study, we investigated whether this association also applies to post-acute neurological early rehabilitation.

Methods

The study included n = 387 patients, admitted to an intensive care or intermediate care unit within 1 year (2016). Among these, 97 patients showed clinical signs of PSH. For each patient with PSH, a patient without PSH was identified, controlling for age, gender, functional and respiratory status upon admission. However, for 25 patients with PSH, there was no suitable control patient fulfilling all defined matching criteria. Primary outcome was type of discharge, dichotomized into favorable (follow-up rehabilitation) and unfavorable outcome (all others). Secondary outcome measures were functional and respiratory status, number of secondary diagnoses, duration of treatment interruptions and length of stay at discharge.

Results

About 25% of neurological early rehabilitation patients showed clinical signs of PSH. A young age (OR = 0.94; CI = 0.91–0.97) and less severe PSH symptoms (OR = 0.79; CI = 0.69–0.90) were independent predictors of a favorable outcome. In addition, severity of PSH symptoms was associated with weaning duration, while the occurrence of PSH symptoms alone had no influence on most secondary outcome variables. The treatment on intermediate care units proved to be longer for patients with PSH symptoms, only.

Conclusions

Patients with PSH represent a large group of neurological early rehabilitation patients. Overall, we did not find PSH-related differences in most of the examined outcome measures. However, severe PSH symptoms seem to be associated with poorer outcome and longer treatment on intermediate care units, in order to prevent possible complications.

Paroxysmal Sympathetic Hyperactivity Syndrome Following Traumatic Brain Injury

Paroxysmal sympathetic hyperactivity (PSH) is a syndrome classified by episodic presentation of abnormal sympathetic and motor symptoms observed in patients with acquired brain injuries. Although the exact physiologic mechanism of PSH is not fully understood, its clinical significance has been well-established. PSH diagnosis depends on the identification of symptom presence, severity, and patterns. Treatment of PSH is rooted in pharmacologic management of targeted symptoms. Although complex, recognition and management of PSH has meaningful implications on the hospitalization and recovery trajectory for adult patients with traumatic brain injuries.

Meaningful Assessment in Patients with Acquired Brain Injuries

There are several key components to the meaningful and comprehensive assessment of patients with acquired brain injuries with respect to management of the upper motor neuron syndrome. Type of brain injury, trajectory of recovery, relevant concomitant complications, development of appropriate goals, and an understanding of resources available for patients are all factors to assess when developing a treatment plan. Using appropriate outcome measures will help monitor the efficacy of interventions and guide ongoing management of spasticity.

Paroxysmal sympathetic hyperactivity syndrome caused by fat embolism syndrome

Paroxysmal sympathetic hyperactivity represents an uncommon and potentially life-threatening complication of severe brain injuries, which are most commonly traumatic. This syndrome is a clinical diagnosis based on the recurrent occurrence of tachycardia, hypertension, diaphoresis, tachypnea, and occasionally high fever and dystonic postures. The episodes may be induced by stimulation or may occur spontaneously. Underdiagnosis is common, and delayed recognition may increase morbidity and long-term disability. Trigger avoidance and pharmacological therapy can be very successful in controlling this complication. Fat embolism syndrome is a rare but serious complication of long bone fractures. Neurologic signs, petechial hemorrhages and acute respiratory failure constitute the characteristic presenting triad. The term cerebral fat embolism is used when the neurological involvement predominates. The diagnosis is clinical, but specific neuroimaging findings can be supportive. The neurologic manifestations include different degrees of alteration of consciousness, focal deficits or seizures. Management is supportive, but good outcomes are possible even in cases with very severe presentation. We report two cases of paroxysmal sympathetic hyperactivity after cerebral fat embolism, which is a very uncommon association.

Regulation of sympathetic vasomotor activity by the hypothalamic paraventricular nucleus in normotensive and hypertensive states

The hypothalamic paraventricular nucleus (PVN) is a unique and important brain region involved in the control of cardiovascular, neuroendocrine, and other physiological functions pertinent to homeostasis. The PVN is a major source of excitatory drive to the spinal sympathetic outflow via both direct and indirect projections. In this review, we discuss the role of the PVN in the regulation of sympathetic output in normal physiological conditions and in hypertension. In normal healthy animals, the PVN presympathetic neurons do not appear to have a major role in sustaining resting sympathetic vasomotor activity or in regulating sympathetic responses to short-term homeostatic challenges such as acute hypotension or hypoxia. Their role is, however, much more significant during longer-term challenges, such as sustained water deprivation, chronic intermittent hypoxia, and pregnancy. The PVN also appears to have a major role in generating the increased sympathetic vasomotor activity that is characteristic of multiple forms of hypertension. Recent studies in the spontaneously hypertensive rat model have shown that impaired inhibitory and enhanced excitatory synaptic inputs to PVN presympathetic neurons are the basis for the heightened sympathetic outflow in hypertension. We discuss the molecular mechanisms underlying the presynaptic and postsynaptic alterations in GABAergic and glutamatergic inputs to PVN presympathetic neurons in hypertension. In addition, we discuss the ability of exercise training to correct sympathetic hyperactivity by restoring blood-brain barrier integrity, reducing angiotensin II availability, and decreasing oxidative stress and inflammation in the PVN.

α2δ-1 couples to NMDA receptors in the hypothalamus to sustain sympathetic vasomotor activity in hypertension

KEY POINTS

α2δ-1 is upregulated, promoting the interaction with NMDA receptors (NMDARs), in the hypothalamus in a rat model of hypertension. The prevalence of α2δ-1-bound NMDARs at synaptic sites in the hypothalamus is increased in hypertensive animals. α2δ-1 is essential for the increased presynaptic and postsynaptic NMDAR activity of hypothalamic neurons in hypertension. α2δ-1-bound NMDARs in the hypothalamus are critically involved in augmented sympathetic outflow in hypertensive animals.

ABSTRACT

Increased glutamate NMDA receptor (NMDAR) activity in the paraventricular nucleus (PVN) of the hypothalamus leads to augmented sympathetic outflow in hypertension. However, the molecular mechanisms underlying this effect remain unclear. α2δ-1, previously considered to be a voltage-activated calcium channel subunit, is a newly discovered powerful regulator of NMDARs. In the present study, we determined the role of α2δ-1 in regulating synaptic NMDAR activity of rostral ventrolateral medulla (RVLM)-projecting PVN neurons in spontaneously hypertensive rats (SHRs). We show that the protein levels of α2δ-1 and NMDARs in synaptosomes and the α2δ-1-NMDAR complexes in the hypothalamus were substantially higher in SHRs than in normotensive control rats. The basal amplitude of evoked NMDAR currents and NMDAR-mediated synaptic glutamate release in RVLM-projecting PVN neurons were significantly increased in SHRs. Strikingly, inhibiting α2δ-1 activity with gabapentin or disrupting the α2δ-1-NMDAR association with an α2δ-1 C-terminus peptide completely normalized the amplitude of evoked NMDAR currents and NMDAR-mediated synaptic glutamate release in RVLM-projecting PVN neurons in SHRs. In addition, microinjection of the α2δ-1 C-terminus peptide into the PVN substantially reduced arterial blood pressure and renal sympathetic nerve discharges in SHRs. Our findings indicate that α2δ-1-bound NMDARs in the PVN are required for the potentiated presynaptic and postsynaptic NMDAR activity of PVN presympathetic neurons and for the elevated sympathetic outflow in hypertension. α2δ-1-bound NMDARs may be an opportune target for treating neurogenic hypertension.

Traumatic Brain Injury Leads to Accelerated Atherosclerosis in Apolipoprotein E Deficient Mice

Traumatic brain injury (TBI) has been associated with atherosclerosis and cardiovascular mortality in humans. However the causal relationship between TBI and vascular disease is unclear. This study investigated the direct role of TBI on vascular disease using a murine model of atherosclerosis. Apolipoprotein E deficient mice were placed on a western diet beginning at 10 weeks of age. Induction of TBI or a sham operation was performed at 14 weeks of age and mice were sacrificed 6 weeks later at 20 weeks of age. MRI revealed evidence of uniform brain injury in all mice subjected to TBI. There were no differences in total cholesterol levels or blood pressure between the groups. Complete blood counts and flow cytometry analysis performed on peripheral blood 6 weeks following TBI revealed a higher percentage of Ly6C-high monocytes in mice subjected to TBI compared to sham-treated mice. Mice with TBI also showed elevated levels of plasma soluble E-selectin and bone marrow tyrosine hydroxylase. Analysis of atherosclerosis at the time of sacrifice revealed increased atherosclerosis with increased Ly6C/G immunostaining in TBI mice compared to sham-treated mice. In conclusion, progression of atherosclerosis is accelerated following TBI. Targeting inflammatory pathways in patients with TBI may reduce subsequent vascular complications.

Autonomic Nervous System Dysfunctions as a Basis for a Predictive Model of Risk of Neurological Disorders in Subjects with Prior History of Traumatic Brain Injury: Implications in Alzheimer's Disease

Autonomic dysfunction is very common in patients with dementia, and its presence might also help in differential diagnosis among dementia subtypes. Various central nervous system structures affected in Alzheimer's disease (AD) are also implicated in the central autonomic nervous system (ANS) regulation. For example, deficits in central cholinergic function in AD could likely lead to autonomic dysfunction. We recently developed a simple, readily applicable evaluation for monitoring ANS disturbances in response to traumatic brain injury (TBI). This ability to monitor TBI allows for the possible detection and targeted prevention of long-term, detrimental brain responses caused by TBI that lead to neurodegenerative diseases such as AD. We randomly selected and extracted de-identified medical record information from subjects who have been assessed using the ANS evaluation protocol. Using machine learning strategies in the analysis of information from individual as well as a combination of ANS evaluation protocol components, we identified a novel prediction model that is effective in correctly segregating between cases with or without a documented history of TBI exposure. Results from our study support the hypothesis that trauma-induced ANS dysfunctions may contribute to clinical TBI features. Because autonomic dysfunction is very common in AD patients it is possible that TBI may also contribute to AD and/or other forms of dementia through these novel mechanisms. This study provides a novel prediction model to physiologically assess the likelihood of subjects with prior history of TBI to develop clinical TBI complications, such as AD.

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.

The preventive effect of dexmedetomidine on paroxysmal sympathetic hyperactivity in severe traumatic brain injury patients who have undergone surgery: a retrospective study

Background

Paroxysmal 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.

Methods

Ninety 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.

Results

The 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.

Conclusion

Dexmedetomidine has a preventive effect on PSH in sTBI patients who have undergone surgery.

Neurogenic Fever

Fever is a relatively common occurrence among patients in the intensive care setting. Although the most obvious and concerning etiology is sepsis, drug reactions, venous thromboembolism, and postsurgical fevers are all on the differential diagnosis. There is abundant evidence that fever is detrimental in acute neurologic injury. Worse outcomes are reported in acute stroke, subarachnoid hemorrhage, and traumatic brain injury. In addition to the various etiologies of fever in the intensive care setting, neurologic illness is a risk factor for neurogenic fevers. This primarily occurs in subarachnoid hemorrhage and traumatic brain injury, with hypothalamic injury being the proposed mechanism. Paroxysmal sympathetic hyperactivity is another source of hyperthermia commonly seen in the population with traumatic brain injury. This review focuses on the detrimental effects of fever on the neurologically injured as well as the risk factors and diagnosis of neurogenic fever.

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.

Critical Care for the Patient With Multiple Trauma

Trauma remains the leading cause of death worldwide and the leading cause of death in those less than 44 years old in the United States. Admission to a verified trauma center has been shown to decrease mortality following a major injury. This decrease in mortality has been a direct result of improvements in the initial evaluation and resuscitation from injury as well as continued advances in critical care. As such, it is vital that intensive care practitioners be familiar with various types of injuries and their associated treatment strategies as well as their potential complications in order to minimize the morbidity and mortality frequently seen in this patient population.

Prehospital hypertension is predictive of traumatic brain injury and is associated with higher mortality

BACKGROUND

The purpose of the current study was to investigate the effect of early adrenergic hyperactivity as manifested by prehospital (emergency medical service [EMS]) hypertension on outcomes of traumatic brain injury (TBI) patients and to develop a prognostic model of the presence of TBI based on EMS and admission (emergency department [ED]) hypertension.

METHODS

This study is a retrospective review of the 2007 to 2008 National Trauma Data Bank including blunt trauma patients 15 years or older with available EMS and ED vital signs. Patients with head Abbreviated Injury Scale (AIS) score of 3 or greater were selected, and mortality was examined within EMS systolic blood pressure (SBP) groups: lower than 100 mm Hg, 110 mm Hg to 150 mm Hg, 160 mm Hg to 180 mm Hg, and 190 mm Hg to 230 mm Hg. A forward logistic regression model including the EMS heart rate, EMS SBP, EMS Glasgow Coma Scale (GCS) score, ED heart rate, and ED SBP was used to identify predictors of a TBI in patients with ED GCS score of less than or equal to 8, 9 to 13, and 14 to 15.

RESULTS

For the 5-year study period, 315,242 patients met inclusion criteria. Adjusted odds for mortality increased in a stepwise fashion with increasing EMS SBP compared with patients with normal EMS SBP (adjusted odds ratio [95% confidence interval], 1.33 [1.22-1.44], p < 0.001, for EMS SBP of 160-180 mm Hg and 1.97 [1.76-2.21], p < 0.001, for EMS SBP of 190-230 mm Hg). A 7-point scoring system was developed for each ED GCS score group to predict the presence of a TBI. EMS SBP of greater than 150 mm Hg and ED SBP of greater than 150 mm Hg were both predictive of the presence of a TBI in patients with ED GCS score of 8 or less and in patients with ED GCS score of 9 to 13 or 14 to 15, respectively.

CONCLUSION

Prehospital hypertension in TBI is associated with a higher mortality risk. Early hypertension in the prehospital setting and at admission can be used to predict the presence of such injuries. These findings may have important early triage and treatment implications.

LEVEL OF EVIDENCE

Prognostic study, level III.

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.

Critical care for patients with massive ischemic stroke

Malignant cerebral edema following ischemic stroke is life threatening, as it can cause inadequate blood flow and perfusion leading to irreversible tissue hypoxia and metabolic crisis. Increased intracranial pressure and brain shift can cause herniation syndrome and finally brain death. Multiple randomized clinical trials have shown that preemptive decompressive hemicraniectomy effectively reduces mortality and morbidity in patients with malignant middle cerebral artery infarction. Another life-saving decompressive surgery is suboccipital craniectomy for patients with brainstem compression by edematous cerebellar infarction. In addition to decompressive surgery, cerebrospinal fluid drainage by ventriculostomy should be considered for patients with acute hydrocephalus following stroke. Medical treatment begins with sedation, analgesia, and general measures including ventilatory support, head elevation, maintaining a neutral neck position, and avoiding conditions associated with intracranial hypertension. Optimization of cerebral perfusion pressure and reduction of intracranial pressure should always be pursued simultaneously. Osmotherapy with mannitol is the standard treatment for intracranial hypertension, but hypertonic saline is also an effective alternative. Therapeutic hypothermia may also be considered for treatment of brain edema and intracranial hypertension, but its neuroprotective effects have not been demonstrated in stroke. Barbiturate coma therapy has been used to reduce metabolic demand, but has become less popular because of its systemic adverse effects. Furthermore, general medical care is critical because of the complex interactions between the brain and other organ systems. Some challenging aspects of critical care, including ventilator support, sedation and analgesia, and performing neurological examinations in the setting of a minimal stimulation protocol, are addressed in this review.

Perioperative critical care management for patients with aneurysmal subarachnoid hemorrhage

Despite significant regional and risk factor-related variations, the overall mortality rate in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) remains high. Compared to ischemic stroke, which is typically irreversible, hemorrhagic stroke tends to carry a higher mortality, but patients who do survive have less disability. Technologies to monitor and treat complications of SAH have advanced considerably in recent years, but good long-term functional outcome still depends on prompt diagnosis, early aggressive management, and avoidance of premature withdrawal of support. Endovascular procedures and open craniotomy to secure a ruptured aneurysm represent some of the numerous critical steps required to achieve the best possible result. In this review, we have attempted to provide a contemporary, evidence-based outline of the perioperative critical care management of patients with SAH. This is a challenging and potentially fatal disease with a wide spectrum of severity and complications and an often protracted course. The dynamic nature of this illness, especially in its most severe forms, requires considerable flexibility in clinician management, especially given the panoply of available treatment modalities. Judicious hemodynamic monitoring and adaptive therapy are essential to respond to the fluctuating nature of cerebral vasospasm and the varying oxygen demands of the injured brain that may readily induce acute or delayed cerebral ischemia.