What Definition Is Used to Describe Second Impact Syndrome in Sports? A Systematic and Critical Review

Video review of the frequency and assessment of head impacts during the FIFA Arab Cup 2021TM

We used injury spotters and video footage review to establish the frequency of head impacts, their characteristics, and the subsequent medical assessment during the FIFA Arab Cup 2021TM. Six defined video signs of potential concussion based on an international consensus were used. A total of 88 head impacts were observed, with a median of 2 (IQR 1.5-4, range 0-7) head impacts per match, of which 44 (50%) resulted in on-pitch medical assessment. The median assessment duration was 51s (IQR 34-65s, range 19-262s). The most common mechanism was head-to-head contact (27% of all impacts and 43% of impacts with medical assessment). Seven head impacts showed video signs of potential concussion: six had one sign and one had two signs. The concussion substitution was used in three incidents. Head impacts during the FIFA Arab Cup were common and a median of 1 head impact per game required an on-pitch medical assessment. Only 8% of the head impacts showed any video sign of potential concussion, and only 3% resulted in a concussion substitution. The medical on-pitch assessments appeared too short (<1 min) to allow an appropriate assessment of all head impacts, indicating a need for further evaluation. Further standardisation of the injury spotter's role in football is recommended.

Continuum of care and longitudinal recovery in a 17-year-old athlete with second impact syndrome

Second impact syndrome (SIS) is an uncommon, but devastating sports-related structural brain injury that results from a second head injury before complete recovery from an initial concussion. The pathophysiology of second impact syndrome is poorly understood, but is hypothesized to involve loss of autoregulation, diffuse cerebral edema, with progression to rapid brain herniation syndromes. Here, we present a case of second impact syndrome in an adolescent high school football player who experienced acute brain herniation and coma. Following stabilization, the patient underwent comprehensive, multidisciplinary rehabilitation in order to achieve significant recovery. A narrative detailing the patient's recovery from one-year post-injury is reviewed.

Heart Rate Variability as a Reliable Biomarker Following Concussion: A Critically Appraised Topic

CLINICAL SCENARIO

Recent systematic reviews show conflicting information regarding the effect of concussion on cardiac autonomic function. Controlled aerobic exercise is the most popular intervention for those recovering from a concussion. There is a gap in the literature supporting the utility of objective metrics during exertional return to play protocols and rehabilitation.

CLINICAL QUESTION

Can heart rate variability (HRV) during physical exertion be a reliable biomarker over time for those who suffered a sport-related concussion?

SUMMARY OF KEY FINDINGS

A literature search produced 3 studies relevant to the clinical question. One, a prospective-matched control group cohort study, reported disturbances in HRV during physical exertion in those with a history of concussion, and identified persistent HRV dysfunction after resolution of subjective complaints, return to play, and with multiple concussive events. Second, a cross-sectional cohort study found an HRV difference in those with and without a history of concussion and in HRV related to age and sex. Finally, the prospective longitudinal case-control cohort study did not find sex or age differences in HRV and concluded that, although postconcussion HRV improved as time passed, resting HRV was not as clinically meaningful as HRV during exertional activities.

CLINICAL BOTTOM LINE

There is emerging evidence to support the use of HRV as an observable biomarker, over time, of autonomic function during physical exertion following a sport-related concussion. However, the meaningfulness of HRV data is not fully understood and the utility seems individualized to the level of athlete, age, and sex and, therefore, cannot be generalizable. In order to be more clinically meaningful and to assist with current clinical decision making regarding RTP, a preinjury baseline assessment would be beneficial as an individualized reference for baseline comparison.

STRENGTH OF RECOMMENDATION

Although HRV is not fully understood, currently, there is grade B evidence to support the use of individualized baseline exertional HRV data as comparative objective metric to assess the autonomic nervous system function, over time, following a concussive event.

Post-Traumatic Epilepsy after Sports-Related Concussion: A Case Report

Sports-related concussions (SRCs) are a public health concern across the United States, and they lead to neurological sequelae that can last long after the event itself. Concussive convulsions at the time of injury are common and rarely require additional workup or treatment. Post-traumatic epilepsy (PTE), however, is a rare phenomenon that can develop after traumatic brain injury and must be managed with adequate medical therapy. Herein we present the case of a 15-year-old football player who developed PTE after an SRC. This condition must be identified through proper education of sports clinicians and those involved in care and management of athletes.

Radiographic and neurobehavioral profile of sports-related concussion associated with scholastic wrestling: a case report

Sports-related concussions (SRCs) are typically characterized by transient neurologic deficits due to physiologic and metabolic brain injury. However, following an SRC, subsequent insults may lead to severe and permanent injury in the affected brain cells. We present the case of a 15-year-old female scholastic wrestler who developed acute encephalopathy, macroscopic white matter injury on imaging, and chronic behavioral changes from inadequate neuro-recovery after a documented SRC. We also compare her case with established SRC data, demonstrating that wrestling-related concussions and repetitive head impacts can produce similar degrees of diffuse neuroinflammation, myelinated axonopathy, blood-brain barrier disruption, and post-concussive symptoms.

Second Impact Syndrome. Myth or reality?

INTRODUCTION

Second impact syndrome (SIS) is a devastating condition occurring in sport-induced mild brain injury. SIS is drastically defined by anamnestic, clinical and radiological criteria, which is unusual in the field of cranial traumatology. The purpose of this study was to provide a literature review of this syndrome.

MATERIAL AND METHODS

We conducted a literature review of all published studies on PubMed. The keywords were "second impact syndrome and catastrophic head injury", "second impact syndrome and sport", "repeat concussion and catastrophic brain injury", "catastrophic head injury and concussion", "catastrophic head injury", "concussion and second impact syndrome", "concussion and repetitive head injury".

RESULTS

Eighty-two full-text articles were assessed for eligibility. Finally, 41 studies were included in qualitative synthesis and 21 were included in quantitative synthesis.

DISCUSSION

The number of cases reported in the literature was extremely small compared to the population at risk, i.e., the number of athletes exposed to repeated concussions. SIS was similar to talk and die syndrome, with which it shares certain characteristics. If we consider SIS according to "talk and deteriorate tables", it opens up interesting perspectives because they are specific in children and adolescents. Taking into account the scarcity of this syndrome, one may question whether athlete-intrinsic features may be involved in at least some cases of SIS. On a pathophysiological level, many explanations remained unsatisfactory because they were unable to explain all the clinical phenomena and observed lesions. Triggering the trigeminocardiac reflex is a crucial element in explaining the sequence of clinical events. Its association with a state of neurogenic inflammation provides an almost complete explanation for this particular condition. Finally, on a practical level, a concussion occurring during the playing of a sport must be considered as any other injury before allowing a return to play.

American Medical Society for Sports Medicine Position Statement on Concussion in Sport

Sport-related concussion (SRC) is a common injury in recreational and organized sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment, and management of SRC. In addition to a growing need for knowledgeable health care professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine formed a writing group to review the existing literature on SRC, update its previous position statement, and address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology, and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short- and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The American Medical Society for Sports Medicine is committed to best clinical practices, evidence-based research, and educational initiatives that positively impact the health and safety of athletes.

American Medical Society for Sports Medicine position statement on concussion in sport

Sport-related concussion (SRC) is a common injury in recreational and organised sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment and management of SRC. In addition to a growing need for knowledgeable healthcare professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine (AMSSM) formed a writing group to review the existing literature on SRC, update its previous position statement, and to address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short-term and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The AMSSM is committed to best clinical practices, evidence-based research and educational initiatives that positively impact the health and safety of athletes.

Anesthesia and concussion

PURPOSE OF REVIEW

As clinicians preparing patients for general anesthesia, should we consider the possibility of concussion in our elective operative patients? If so, why is this necessary? Is it possible that exposure to an anesthetic is detrimental to recovery from concussion? If so, what should we do about the imperative/urgency for surgery? No answers are promised in this review. Rather, the focus is on the questions and approaches taken in the recent literature, as well as highlighting a need for more research.

RECENT FINDINGS

Surgery, pain and general anesthesia all influence autonomic nervous system responses. Intravenous and inhalational anesthetic agents are also known to have variable effects on the cerebrovascular reactivity (CVR) to carbon dioxide (CO2). This review adds to this general information the recent, specific physiologic alterations seen after concussion in autonomic system function and the CVR to CO2.

SUMMARY

This review provides a perspective about autonomic nervous system function and cerebrovascular effects of concussion, and some relevant clinical issues that warrant further clinical study.

An update on diagnostic and prognostic biomarkers for traumatic brain injury

INTRODUCTION

Traumatic brain injury (TBI) is a major worldwide neurological disorder of epidemic proportions. To date, there are still no FDA-approved therapies to treat any forms of TBI. Encouragingly, there are emerging data showing that biofluid-based TBI biomarker tests have the potential to diagnose the presence of TBI of different severities including concussion, and to predict outcome. Areas covered: The authors provide an update on the current knowledge of TBI biomarkers, including protein biomarkers for neuronal cell body injury (UCH-L1, NSE), astroglial injury (GFAP, S100B), neuronal cell death (αII-spectrin breakdown products), axonal injury (NF proteins), white matter injury (MBP), post-injury neurodegeneration (total Tau and phospho-Tau), post-injury autoimmune response (brain antigen-targeting autoantibodies), and other emerging non-protein biomarkers. The authors discuss biomarker evidence in TBI diagnosis, outcome prognosis and possible identification of post-TBI neurodegernative diseases (e.g. chronic traumatic encephalopathy and Alzheimer's disease), and as theranostic tools in pre-clinical and clinical settings. Expert commentary: A spectrum of biomarkers is now at or near the stage of formal clinical validation of their diagnostic and prognostic utilities in the management of TBI of varied severities including concussions. TBI biomarkers could serve as a theranostic tool in facilitating drug development and treatment monitoring.