Paroxysmal episodic hypothalamic instability with hypothermia after traumatic brain injury

A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 1: Foundational principles and theories of regulation

This contribution is the first of a four-part, historical series encompassing foundational principles, mechanistic hypotheses and supported facts concerning human thermoregulation during athletic and occupational pursuits, as understood 100 years ago and now. Herein, the emphasis is upon the physical and physiological principles underlying thermoregulation, the goal of which is thermal homeostasis (homeothermy). As one of many homeostatic processes affected by exercise, thermoregulation shares, and competes for, physiological resources. The impact of that sharing is revealed through the physiological measurements that we take (Part 2), in the physiological responses to the thermal stresses to which we are exposed (Part 3) and in the adaptations that increase our tolerance to those stresses (Part 4). Exercising muscles impose our most-powerful heat stress, and the physiological avenues for redistributing heat, and for balancing heat exchange with the environment, must adhere to the laws of physics. The first principles of internal and external heat exchange were established before 1900, yet their full significance is not always recognised. Those physiological processes are governed by a thermoregulatory centre, which employs feedback and feedforward control, and which functions as far more than a thermostat with a set-point, as once was thought. The hypothalamus, today established firmly as the neural seat of thermoregulation, does not regulate deep-body temperature alone, but an integrated temperature to which thermoreceptors from all over the body contribute, including the skin and probably the muscles. No work factor needs to be invoked to explain how body temperature is stabilised during exercise.

Targeting hydrogen sulfide and nitric oxide to repair cardiovascular injury after trauma

The systemic cardiovascular effects of major trauma, especially neurotrauma, contribute to death and permanent disability in trauma patients and treatments are needed to improve outcomes. In some trauma patients, dysfunction of the autonomic nervous system produces a state of adrenergic overstimulation, causing either a sustained elevation in catecholamines (sympathetic storm) or oscillating bursts of paroxysmal sympathetic hyperactivity. Trauma can also activate innate immune responses that release cytokines and damage-associated molecular patterns into the circulation. This combination of altered autonomic nervous system function and widespread systemic inflammation produces secondary cardiovascular injury, including hypertension, damage to cardiac tissue, vascular endothelial dysfunction, coagulopathy and multiorgan failure. The gasotransmitters nitric oxide (NO) and hydrogen sulfide (H2S) are small gaseous molecules with potent effects on vascular tone regulation. Exogenous NO (inhaled) has potential therapeutic benefit in cardio-cerebrovascular diseases, but limited data suggests potential efficacy in traumatic brain injury (TBI). H2S is a modulator of NO signaling and autonomic nervous system function that has also been used as a drug for cardio-cerebrovascular diseases. The inhaled gases NO and H2S are potential treatments to restore cardio-cerebrovascular function in the post-trauma period.

Prognostic Value of Circadian Rhythm of Brain Temperature in Traumatic Brain Injury

Hypothermia has been used in postoperative management of traumatic brain injury (TBI); however, the rhythmic variation and prognostic value of brain temperature after TBI have never been studied. This study describes diurnal brain temperature patterns in comatose patients with TBI. Mesors of brain temperature, amplitude, and acrophase were estimated from recorded temperature measurements using cosinor analysis. The association of these patterns with clinical parameters, mortality, and functional outcomes in a 12-month follow-up was examined. According to the cosinor analysis, 59.3% of patients presented with circadian rhythms of brain temperature in the first 72 h postoperatively. The rhythm-adjusted mesor of brain temperature was 37.39 ± 1.21 °C, with a diminished mean amplitude of 0.28 (±0.25) °C; a shift of temperature acrophase was also observed. Multivariate logistic regression analysis revealed that initial Glasgow coma scale score, age, elevated blood glucose level, and circadian rhythm of brain temperature seemed to be predictive and prognostic factors of patients' functional outcomes. For the prediction of survival status, younger patients or those patients with mesor within the middle 50% of brain temperature were more likely to survive. The analysis of brain temperature rhythms in patients with moderate and severe TBI provided additional predictive information related to mortality and functional outcomes.

Performance of Modified Early Warning Score (MEWS) for Predicting In-Hospital Mortality in Traumatic Brain Injury Patients

The present study aimed to analyze and compare the prognostic performances of the Revised Trauma Score (RTS), Injury Severity Score (ISS), Shock Index (SI), and Modified Early Warning Score (MEWS) for in-hospital mortality in patients with traumatic brain injury (TBI). This retrospective observational study included severe trauma patients with TBI who visited the emergency department between January 2018 and December 2020. TBI was considered when the Abbreviated Injury Scale was 3 or higher. The primary outcome was in-hospital mortality. In total, 1108 patients were included, and the in-hospital mortality was 183 patients (16.3% of the cohort). Receiver operating characteristic curve analyses were performed for the ISS, RTS, SI, and MEWS with respect to the prediction of in-hospital mortality. The area under the curves (AUCs) of the ISS, RTS, SI, and MEWS were 0.638 (95% confidence interval (CI), 0.603–0.672), 0.742 (95% CI, 0.709–0.772), 0.524 (95% CI, 0.489–0.560), and 0.799 (95% CI, 0.769–0.827), respectively. The AUC of MEWS was significantly different from the AUCs of ISS, RTS, and SI. In multivariate analysis, age (odds ratio (OR), 1.012; 95% CI, 1.000–1.023), the ISS (OR, 1.040; 95% CI, 1.013–1.069), the Glasgow Coma Scale (GCS) score (OR, 0.793; 95% CI, 0.761–0.826), and body temperature (BT) (OR, 0.465; 95% CI, 0.329–0.655) were independently associated with in-hospital mortality after adjustment for confounders. In the present study, the MEWS showed fair performance for predicting in-hospital mortality in patients with TBI. The GCS score and BT seemed to have a significant role in the discrimination ability of the MEWS. The MEWS may be a useful tool for predicting in-hospital mortality in patients with TBI.

Theoretical basis for the use of non-invasive thermal measurements to assess the brain injury in newborns undergoing therapeutic hypothermia

The aim of this paper is to propose a new non-invasive methodology to estimate thermogenesis in newborns with perinatal asphyxia (PA) undergoing therapeutic hypothermia (TH). Metabolic heat production (with respect to either a neonate’s body mass or its body surface) is calculated from the newborn’s heat balance, estimating all remaining terms of this heat balance utilising results of only non-invasive thermal measurements. The measurement devices work with standard equipment used for therapeutic hypothermia and are equipped with the Global System for Mobile Communications (GSM), which allows one to record and monitor the course of the therapy remotely (using an internet browser) without disturbing the medical personnel. This methodology allows one to estimate thermogenesis in newborns with perinatal asphyxia undergoing therapeutic hypothermia. It also offers information about instantaneous values of the rate of cooling together with values of remaining rates of heat transfer. It also shows the trend of any changes, which are recorded during treatment. Having information about all components of the heat balance one is able to facilitate comparison of results obtained for different patients, in whom these components may differ. The proposed method can be a new tool for measuring heat balance with the possibility of offering better predictions regarding short-term neurologic outcomes and tailored management in newborns treated by TH.

Acute basilar artery occlusion with recurrent shivering: A case report

RATIONALE

Shivering is an important physiological response of the body that causes muscle tremors to maintain temperature homeostasis. Traumatic brain injuries that affect the hypothalamus cause hypothermia, and physical removal of suprasellar tumors causes thermoregulation imbalance. However, no study has reported shivering due to ischemic stroke.

PATIENT CONCERNS

A 58-year-old male patient was admitted to our emergency department to evaluate severe stenosis of the basilar artery. While waiting for further examination, he exhibited coarse shivering and severe dysarthria.

DIAGNOSIS

Brain computed tomography angiography revealed occlusion of the entire basilar artery, and cerebral hypoperfusion was diagnosed in that area.

INTERVENTIONS

Transfemoral cerebral angiography (TFCA) was immediately performed, followed by thrombectomy of the basilar artery.

OUTCOMES

Neurological deficits, including shivering, were rapidly reversed. The same symptom reoccurred 5 hours later, and TFCA was performed for thrombectomy and stenting, and neurological symptoms immediately reversed. The patient's neurological symptoms did not worsen during hospitalization.

LESSONS

Patients with acute basilar artery occlusion need prompt management because they have a higher mortality rate than those with other intracranial artery occlusions. When a patient exhibits neurological deficits accompanied by abrupt shivering for no specific reason, basilar artery occlusion must be considered.

The Impact of Accidental Hypothermia on Mortality in Trauma Patients Overall and Patients with Traumatic Brain Injury Specifically: A Systematic Review and Meta-Analysis

Background

Accidental hypothermia is a known predictor for worse outcomes in trauma patients, but has not been comprehensively assessed in a meta-analysis so far. The aim of this systematic review and meta-analysis was to investigate the impact of accidental hypothermia on mortality in trauma patients overall and patients with traumatic brain injury (TBI) specifically.

Methods

This is a systematic review and meta-analysis using the Ovid Medline/PubMed database. Scientific articles reporting accidental hypothermia and its impact on outcomes in trauma patients were included in qualitative synthesis. Studies that compared the effect of hypothermia vs. normothermia at hospital admission on in-hospital mortality were included in two meta-analyses on (1) trauma patients overall and (2) patients with TBI specifically. Meta-analysis was performed using a Mantel–Haenszel random-effects model.

Results

Literature search revealed 264 articles. Of these, 14 studies published 1987–2018 were included in the qualitative synthesis. Seven studies qualified for meta-analysis on trauma patients overall and three studies for meta-analysis on patients with TBI specifically. Accidental hypothermia at admission was associated with significantly higher mortality both in trauma patients overall (OR 5.18 [95% CI 2.61–10.28]) and patients with TBI specifically (OR 2.38 [95% CI 1.53–3.69]).

Conclusions

In the current meta-analysis, accidental hypothermia was strongly associated with higher in-hospital mortality both in trauma patients overall and patients with TBI specifically. These findings underscore the importance of measures to avoid accidental hypothermia in the prehospital care of trauma patients.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05750-5) contains supplementary material, which is available to authorized users.

Late-onset post-lesional paroxysmal hypothermia: a case series and literature review

BACKGROUND

Paroxysmal hypothermia (PH) is a rare condition characterized by recurrent episodes of spontaneous hypothermia, bradycardia, disorders of consciousness and, in some cases, hyperhidrosis. When associated with a detectable hypothalamic lesion, PH episodes usually occur shortly after the brain insult.

METHODS

We performed a retrospective study to identify patients who had demonstrated at least one episode of symptomatic spontaneous PH as defined by (i) tympanic temperature < 35 °C; (ii) drowsiness and/or confusion state and/or coma; (iii) duration of the episode ≥ 24 h; (iv) absence of other condition resulting in hypothermia RESULTS: Among 8824 patients, we identified four patients with recurrent late-onset PH episodes of 1-26-day duration that occurred 6-46 years after the brain insult. The lesion always involved the diencephalon. All patients suffered from epilepsy and three of hypopituitarism. PH episode typically included severe hypothermia, bradycardia, drowsiness, thrombocytopenia and in some patients central hypoventilation and narcolepsy-like hypersomnia. In ¼ of episodes, confusion was mistaken as non-convulsive epileptic manifestation resulting in benzodiazepine administration which aggravated symptoms. In the two patients with nocturnal hypoventilation, chronic non-invasive ventilation with bi-level positive airway pressure allowed cessation of symptomatic episodes.

DISCUSSION

Late-onset post-lesional PH is exceptional with only a single case hitherto reported in the literature. Distinguishing hypothermia-related disturbances of consciousness from epileptic seizures or post-ictal phenomena is crucial since treatment with benzodiazepines may worsen hypothermia through their action on GABAa receptors. Lastly, PH may be associated with sleep disorders and hypoventilation, for which investigations and treatment should be considered.

Dysautonomia secondary to third ventriculostomy successfully managed with midodrine

Hypothalamic lesions can compromise its essential regulatory roles resulting in critical disruption of temperature and blood pressure homoeostasis. We present the case of a 55-year-old woman who had been previously submitted to several neurosurgical procedures aimed at treating idiopathic hydrocephalus. She presented to our department with recurring episodes of hypothermia and wide blood pressure variations, which had been worsening over the last few years. After extensive complementary workup, which excluded new neurological lesions or endocrinological conditions, hypothalamic dysfunction was assumed to be the cause of this syndrome. She was successfully treated with midodrine and on-demand captopril, which resulted in adequate control of her blood pressure. This case highlights the rare and unpredictable consequences of damage to the hypothalamus, depicting the favourable result of a heretofore unpublished medical approach.

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.

A retrospective analysis of paroxysmal sympathetic hyperactivity following severe pediatric brain injury

BACKGROUND

There are several gaps in the literature related to the prognosis and care of children who have experienced a brain injury then develop paroxysmal sympathetic hyperactivity (PSH).

OBJECTIVE

The objective of the present study was to explore the characteristics and prognosis of children who have experienced severe brain injury and developed PSH.

METHODOLOGY

A secondary analysis was conducted using an established clinical dataset of children who had experienced severe brain injury and were admitted to an academic children's rehabilitation center (n= 83).

RESULTS

Those children with PSH had a significantly longer acute care length of stay (p= 0.024) and total length of stay (p= 0.034) compared with those without PSH. There was no significant difference in cognitive and motor function or transition to rehabilitation between those with and those without PSH after controlling for age and etiology of injury.

IMPLICATIONS

The findings from the present study reveal factors regarding the elusive phenomenon of PSH among children.

Paroxysmal Sympathetic Hyperactivity in Children: An Exploratory Evaluation of Nursing Interventions

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) produces symptoms of autonomic instability and muscle over-activity; however, the majority of nursing interventions used in clinical practice are anecdotal and not evidenced based.

OBJECTIVE

The primary objective was to report nursing documentation of PSH events, and to describe the clinical nursing interventions and care provided to children who have suffered a severe brain injury and are exhibiting PSH. The secondary objective was to demonstrate how the Symptom Management Theory (SMT) can serve as a framework for research related to brain injury and PSH.

METHODOLOGY

The study consisted of a retrospective chart review of nursing progress notes using direct content analysis. The nested sample of ten randomly selected charts was chosen from a larger quantitative study of 83 children who had suffered severe brain injuries with and without PSH. Textual analysis of verbatim nursing progress notes was used to describe nursing interventions that were used and documented for this patient population.

RESULTS

The priority nursing interventions to manage these symptoms included medication administration, facilitation of family presence, and strategies to target auditory, tactile, and visual stimuli. The sample received different individual interventions for PSH. Additionally, individual subjects demonstrated different patterns of interventions.

IMPLICATIONS

While tactile interventions were documented most frequently, there was not a uniform approach to interventions. The SMT can be useful to provide a framework that organizes and tests clinical care and management of PSH strategies.

A Proteomic Evaluation of Sympathetic Activity Biomarkers of the Hypothalamus-Pituitary-Adrenal Axis by Western Blotting Technique Following Experimental Traumatic Brain Injury

Endocrine disorders and autonomic dysfunction are common paradigms following traumatic brain injury (TBI). Alterations in the hypothalamus-pituitary-adrenal (HPA) axis following TBI may result in impaired vasopressor response, energy imbalance, fatigue, depression, or neurological disorders. Autonomic dysfunction is a common disorder following TBI. The sympathetic activity markers on HPA axis can be measured by Western blot protein analysis. Tyrosine hydroxylase, dopamine beta hydroxylase are the key enzymes for the synthesis of norepinephrine; and neuropeptide Y (NPY) is the peptide that is co-stored and co-released with norepinephrine. Thus, the present chapter reviews the experimental protocols for Western blot protein analysis for the measurement of biomarkers that indicate sympathetic activity in brain regions (hypothalamus, pituitary, cerebral cortex, and cerebellum) following TBI.

Paroxysmal sympathetic hyperactivity: Autonomic instability and muscle over-activity following severe brain injury

BACKGROUND

Children who suffer from moderate-to-severe brain injury can develop a complicating phenomenon known as paroxysmal sympathetic hyperactivity (PSH), characterized by autonomic instability and identified clinically as a cluster of symptoms that can include recurrent fever without a source of infection, hypertension, tachycardia, tachypnea, agitation, diaphoresis and dystonia. Studies with adults have demonstrated that this cluster of symptoms is associated with poorer clinical outcomes (prolonged hospitalizations, poorer cognitive and motor function). However, there have been limited studies in children with PSH.

OBJECTIVE

To present a literature review regarding PSH following severe brain injury and highlight research needs in children with PSH.

METHODOLOGY

Electronic databases (CINAHL, Ovid Medline, Web of Science and Google Scholar) were searched.

RESULTS

Thirty-one research articles met the criteria for inclusion. Several themes emerged regarding the phenomenon of interest during the review: nomenclature, symptoms, management and differences between children and adults.

IMPLICATIONS

The majority of the research regarding PSH following severe brain injury has been descriptive in nature. Few studies, however, have explored PSH in children with brain injury; therefore, little is known about whether the outcomes of children with PSH are different and, if so, in what ways.

The young brain and concussion: imaging as a biomarker for diagnosis and prognosis

Concussion (mild traumatic brain injury (mTBI)) is a significant pediatric public health concern. Despite increased awareness, a comprehensive understanding of the acute and chronic effects of concussion on central nervous system structure and function remains incomplete. Here we review the definition, epidemiology, and sequelae of concussion within the developing brain, during childhood and adolescence, with current data derived from studies of pathophysiology and neuroimaging. These findings may contribute to a better understanding of the neurological consequences of traumatic brain injuries, which in turn, may lead to the development of brain biomarkers to improve identification, management and prognosis of pediatric patients suffering from concussion.

A review of paroxysmal sympathetic hyperactivity after acquired brain injury

Severe excessive autonomic overactivity occurs in a subgroup of people surviving acquired brain injury, the majority of whom show paroxysmal sympathetic and motor overactivity. Delayed recognition of paroxysmal sympathetic hyperactivity (PSH) after brain injury may increase morbidity and long-term disability. Despite its significant clinical impact, the scientific literature on this syndrome is confusing; there is no consensus on nomenclature, etiological information for diagnoses preceding the condition is poorly understood, and the evidence base underpinning our knowledge of the pathophysiology and management strategies is largely anecdotal. This systematic literature review identified 2 separate categories of paroxysmal autonomic overactivity, 1 characterized by relatively pure sympathetic overactivity and another group of disorders with mixed parasympathetic/sympathetic features. The PSH group comprised 349 reported cases, with 79.4% resulting from traumatic brain injury (TBI), 9.7% from hypoxia, and 5.4% from cerebrovascular accident. Although TBI is the dominant causative etiology, there was some suggestion that the true incidence of the condition is highest following cerebral hypoxia. In total, 31 different terms were identified for the condition. Although the most common term in the literature was dysautonomia, the consistency of sympathetic clinical features suggests that a more specific term should be used. The findings of this review suggest that PSH be adopted as a more clinically relevant and appropriate term. The review highlights major problems regarding conceptual definitions, diagnostic criteria, and nomenclature. Consensus on these issues is recommended as an essential basis for further research in the area.

Hypothalamic-pituitary axis deficiency following traumatic brain injury in a dog

OBJECTIVE

To describe endocrine dysfunction associated with traumatic brain injury in a dog.

SUMMARY

A 12-week-old dog presented with traumatic brain injury and did not respond to traditional supportive care. Continued hypothermia, electrolyte derangements, hypotension, and hyposthenuria prompted screening for and detection of several hypothalamic-pituitary disorders including: hypoadrenocorticism, central diabetes insipidus, hypothyroidism, and growth hormone deficiency. Electrolyte abnormalities, urine osmolarity, and blood pressure improved with treatment for the associated disorders.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report of generalized hypothalamic-pituitary dysfunction or panhypopituitarism following traumatic brain injury in a dog.