About this course:
The purpose of this module is to provide an overview of the nature of concussions: their definition, pathophysiology, signs/symptoms, diagnosis and treatment. This module will also review the clinical sequelae that can result as a consequence of repeated concussions and highlights prevention and management strategies.
At the end of this module, the learner will be able to:
- Define the term concussion (‘traumatic brain injury’) and how to diagnose a concussion
- Recall thecommon signs and symptoms of a concussion and identify red flags that require immediate and urgent evaluation
- Classify the severity of a concussion based on standard criteria [mild, moderate, severe]
- Demonstrate understanding of standard concussion management
- Understand the considerations involved in return-to-school/work/play
- Describe concussion prevention strategies and identify high risk populations
- Recognize the signs of post concussive syndrome and chronic traumatic encephalopathy
According to the Centers for Disease Control and Prevention (CDC, 2019), concussion has become a prominent issue in medicine and is increasingly recognized as a major public health issue contributing to significant morbidity, permanent disability and mortality. Heightened media coverage surrounding the long-term effects of sports-related head injuries in professional athletes has sparked interest among health care professionals, coaches, parents, athletes, and has raised awareness among the general public (Chadehumbe, 2016; Corrigan, Harrison-Felix, & Haarbauer-Krupa, 2019). While the majority of patients will return to baseline and experience a full recovery following a concussion, a subset will endure persistent symptoms and effects (Martin, 2017). Individuals who sustain repetitive concussive injuries are at increased risk for experiencing prolonged impairments and deficits (Kamins & Giza, 2016). Long-term neuropsychiatric testing on athletes who have sustained frequent concussions has demonstrated that multiple concussions over a lifetime can lead to irremediable cognitive impairment, and appropriate management is critical for improving long-term outcomes (Choe, 2016).
What is a Concussion?
A concussion, otherwise known as a mild traumatic brain injury (mTBI), is a “disruption of brain function and/or structure due to the application of an external physical force that produces signs and symptoms of brain dysfunction in the acute injury period” (Corrigan, et al., 2019, p 3). Essentially, a force outside the body, shakes the head and induces harm to the brain (Martin, 2017).The brain injury may arise directly from the forceful blunt or penetrating trauma to the head or from acceleration/deceleration forces, inducing a clinical sequela of symptoms (Corrigan et al.,2019). The term concussion is not well-defined among medical communities and organizations, and descriptions are often inconsistent as a consensus has yet to emerge (Bodin, Yeates, & Klamar, 2012). These inconsistencies lead to confusion among patients, family members and health care professionals regarding the importance of the diagnosis. Based on a practice-changing 2010 research study, DeMatteo and colleagues found that when a patient is admitted to the hospital, the term ‘concussion’ unintentionally communicates to the medical team that a ‘brain injury’ did not actually occur (DeMatteo et al., 2010). As a result, current guidelines recommend that healthcare providers use the terms mTBI or TBI instead of concussion, as it denotes the seriousness of the injury (Bodin et al., 2012). For purposes of this educational module, the term concussion will be used interchangeably with the term mTBI. It is important to recognize that not all bumps, blows, or forceful trauma to the head result in a mTBI, and not all individuals who endure a mTBI will have associated cognitive and physical deficits (Corrigan et al., 2019). The impact of a mTBI on brain function can present uniquely and damage can occur to varying degrees based on the extent of the injury; which is why it is critical to understand the mechanism of the injury and signs to monitor for (Corrigan et al., 2019). No two concussions have an identical disease trajectory or outcome (Martin, 2017).The location of the impact has no defined prognosis or outcome, although evidence supports that trauma to the top of the head does carry an increased risk for loss of consciousness (Kamins & Giza, 2016).
The CDC (2019) reports 2.87 million TBI-related emergency department visits, hospitalizations, and deaths in 2014; however, many people who sustain a TBI do not seek care in a hospital and are therefore not represented within this number. According to Traumatic Brain Injury Model Systems (TBIMS), the most common injury mechanism for mTBI among all age groups is falls (TBIMS, 2019). Other etiologies include being struck by or against an object, motor vehicle collisions, violent assaults, military duties (such as explosions), or as a result of playing contact sports (Corrigan et al., 2019, p. 4). While the majority of TBIs are mild and nearly 80-90% of cases resolve within 3 weeks, proper evaluation, management and treatment is critical (TBIMS, 2019).
A mTBI occurs when a mechanical force or trauma occurs to the head, neck, or body, resulting in the rotational acceleration of the brain within the skull(Martin, 2017). The brain moves rapidly back and forth inside the skull, leading to a cascade of events within the brain such as chemical changes, neuronal depolarization, metabolic derangements at the cellular level, and decreased blood flow (Choe, 2016). The stretching, damage, and/or death of brain cells associated with the injury subsequentlyprovokes a clinical syndrome characterized by immediate and/or transient alteration in brain function (American Association of Neurological Surgeons [AANS], 2019).
Traumatic brain injuries are classified in regard to the primary event (primary brain injury), and thesecondary event (secondary brain injury). The primary event refers to the damage resulting from the sudden impact, such as the immediate bruising, skull fracture, and/or tearing of the brain tissue (Shimoda, Yokobori, & Bullock, 2019). The secondary event encompasses the damage that evolves later as a consequence of the body and brain’s biological responses following the primary injury (Shimoda et al., 2019). This can include swelling within the brain causing pressure on brain tissue and leading to more damage as a consequence. Morbidity from a secondary event can be more severe than damage from the primary event (Romeu-Mejia, Giza, & Goldman, 2019; Shimoda et al., 2019).
PRIMARY EVENTS (THE INITIAL TRAUMA)
- Tearing of brain cells (axonal shearing)—When an outside force strikes the head, the brain can bang back and forth inside the inflexible skull. Since the brain is soft and pliable, and brain cells are fragile, the cells can be stretched to a point of tearing known as axonal shearing. When this occurs, the damaged brain cells die (Shimoda et al., 2019)
- Contusion—When the brain crashes against the inside of the hard skull, small blood vessels can be torn, resulting in one or more contusions (bruising and bleeding). This can cause disability and death of brain cells (Romeu-Mejia et al., 2019; Shimoda et al., 2019)
- Skull fracture— When skull bones are cracked or broken, they may press on the brain and/or penetrate the brain with shards of broken bone. In the event of an open skull fracture, in which the outside environment comes in contact with the cranial cavity, there is an associated risk of hemorrhage and infection (Corrigan et al., 2019).
- Coup-contracoup Injury— Brain damage can occur at the point of impact (coup), as well as the direct opposite (contracoup) (Shimoda et al., 2019). This is a consequence of the forward and backward motion (acceleration/decelera
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SECONDARY EVENTS (THE BODY & BRAIN RESPONSE TO THE TRAUMA)
- Brain swelling (edema)—After an injury, the brain swells just like any other traumatic injury that occurs throughout the body. However, because the brain is placed inside a rigid shell (the skull), there is no ability for the skull to expand and accommodate the increased tissue volume resulting from the swollen brain cells (Bodin et al., 2012). Swelling inside the skull is dangerous and can cause damage by interrupting the flow of blood and oxygen to brain tissue (Choe, 2016). Severe swelling can lead to increased intracranial pressure (ICP), which may apply pressure on the brain stem, and consequently lead to death (Kamins & Giza, 2016).
- Hematoma- If damaged blood vessels are large, they can develop into a hematoma (a collection of blood outside of blood vessels) inside the skull (Kamins & Giza, 2016). A hematoma can increase pressure on the brain and surgery may be required to drain the blood out of the skull (Choe, 2016).
- Shock- With more severe brain injuries, there may be an associated loss of blood to the brain caused by the injured cells and tissue, and the body's shock response may kick in (Romeu-Mejia et al., 2019). Shock is the body’s defense mechanism to a sudden and life-threatening drop in blood pressure, in which the body reacts by inducing vasoconstriction (Shimoda et al., 2019). Vasoconstriction is a narrowing of blood vessels in the extremities to conserve blood flow to the vital organs, such as the heart and brain (Choe, 2016).
Vulnerable and at-risk populations
Anyone can endure a mTBI, but some individuals are at higher risk than the general population (CDC, 2019). About twice as many males as females have a TBI, and the risk is highest among younger people up to 19 years of age and older individuals over the age of 65 (Corrigan et al., 2019). National data reveals that African Americans have the highest death rate from TBI (TBIMS, 2019).In addition, individuals who have had a TBI before are at higher risk of having another and for enduring long-term complications and post-concussive syndrome (Martin, 2017). Amongchildren and adolescents, injuries induced by a TBI occur during a critical time of brain development, rendering this population more vulnerable to long-term sequelae (Martin, 2017).Unlike the popular myth that children are more resilient, their brains are not (Chadehumbe 2016; Corrigan et al., 2019).
The signs and symptoms of mTBI may appear immediately after the injury with arapid onset of temporary impairment of neurological function that resolves spontaneously, or symptomsmay evolve after several minutes or hours following the trauma (Kamins & Giza, 2016). Symptoms may last for days, weeks, or months. In rare cases, symptoms may persist for years (AANS, 2019; Chadehumbe, 2016). Confusion is the hallmark symptom andthere are 3 principal features of confusion: (a) inability to maintain a coherent stream of thought, (b) disturbance of awareness with heightened distractibility, and (c) inability to carry out a sequence of goal-directed movements (Choe, 2016; Shimoda et al., 2019).
A mTBI may or may not involve loss of consciousness (LOC), but not in most cases (Shimoda et al., 2019). In general, symptoms of mTBI fall into four distinct categories: physical (somatic), sleep, cognitive, and emotional. A validated concussive scale should be used to assess symptoms (Bramley et al., 2016). See Table 1.1 for a list of the most common symptoms of mTBI as organized by category.
Diagnosis and Evaluation
Diagnosis is predominantly reliant on the nature of the incident, the presence of specific symptoms, and the skill of the clinician evaluating the patient (AANS, 2019). A diagnosis of mTBI should be considered when one or more abnormalities of brain function are noted after an identified traumatic head injury has occurred (Kamins & Giza, 2016). Since a mTBI primarily reflects a transient disturbance in brain functioning, it is not typically associated with structural injuries detected on routine neuroimaging studies (Martin, 2017). Therefore, diagnostic tests usually will not show any changes, and healthcare providers are advised to not routinely perform computed tomography (CT) imaging, magnetic resonance (MRI) imaging, or skull x-rays when screening or diagnosing TBI, due to unnecessary radiation exposure (AANS, 2019). However, it iscritical to identify and rule out patients at risk for intracranial injury (ICI), whom may need imaging of the head (Stein, Feather, & Napolitano, 2017). See Table 1.2 for a list of warning signs that require immediate and urgent evaluation.
While trauma to the head, neck, or body is a primary characteristic of mTBI, there are several common features that are used clinically to define the nature of a head injury (Corrigan et al., 2019). The conclusive definition of ‘concussion’ versus ‘mTBI’ remains variable throughout the literature. However, the leading organizations devoted to brain injury research such as The American Congress of Rehabilitation Medicine (ACRM), American Academy of Pediatrics (AAP) and the World Health Organizations (WHO) universally emphasize four primary diagnostic criteria: level of consciousness, posttraumatic amnesia, mental status, and neurological signs (Bodin et al., 2012). Refer to Table 1.3.
A thorough history taking for patients who present with suspected trauma to the head is essential (Corrigan et al., 2019). Key information to obtain include the following:
- The nature of the head trauma,
- History of prior head trauma,
- Prior or current military duties and trauma,
- Current medications,
- Alcohol and drug use patterns,
- Past medical history including any comorbid conditions (AANS, 2019).
It is critical to initially evaluate all head trauma patients for cervical spine damage and scalp/skull fracture. An examination of the head and neck should be completed, looking for signs of basal skull fracture such as:
- Cerebral spinal fluid leakage (clear fluid) from nose or ears,
- Blood behind eardrum,
- Bruising around eyes or behind ears,
- Weakness of face,
- Loss of hearing or smell,
- Loss of vision or double vision,
These signs on physical exam can be indicative of more severe intracranial injuries and may warrant further diagnostic imaging (such as CT scan or MRI scan of the brain) (Martin, 2017).A comprehensive neurological exam should be completed, including:
- Cranial nerves,
- Coordination, gait, balance,
- Sensory exam,
- Motor exam,
- Visual Field Testing,
If concern exists, an eye exam should be performed by an optometrist or ophthalmologist to detect dysfunction in central and peripheral vision caused by medical conditions and other neurologic deficits. Visual field defects can result from injury to the visual pathways including retinal injury, optic neuropathy and structural brain injury or pathologies (Chadehumbe, 2016). Neuropsychological testing is not required for all patients, but can be helpful in guiding management for patients with cognitive deficits. A variety of approaches can be utilized for this, such as computerized, paper, or hybrid. Any testing performed should be performed by a trained psychometrician and all interpretation of results should be performed by a certified neuropsychologist. (Chadehumbe, 2016; Martin, 2017). Electroencephalogram (EEG) is an electrophysiological monitoring test used to identify any problems related to electrical activity of the brain. An EEG should be performed if seizures are witnessed or suspected (Martin, 2017).
Classification of Traumatic Brain Injury
The severity of a mTBI is classified along a clinical and pathological continuum ranging from mild to severe, with symptoms varying from a headache or brief change in mental state to extended periods of unconsciousness, coma, or death (Stein et al., 2017). The severity of symptoms when the injury first occurs does not necessarily predict the extent of future symptoms (Martin, 2017). It is not possible to accurately predict at the time of the injury which patients will recover rapidly and which will go on to have persistent symptoms and deficits (Martin, 2017). As a result, guidelines and scales have been developed to grade TBI severity and medical professionals are trained to use validated symptom scales to determine severity of the injury. These tools are critical aspects that help guidemedical decision making, allow for the tracking of changes following treatment, and improve the patient’s outcome (Martin, 2017).
The CDC (2019) offers a list of age-appropriate validated neuropsychological tools to assess severity of symptoms. The Glasgow Coma Scale (GCS) is one of the most widely utilized measures to determine severity of the injury. Some other commonly used and validated tools include:
- Post-Concussion Symptom Scale,
- Health and Behavior Inventory,
- Post-Concussion Symptom Inventory,
- Acute Concussion Evaluation (CDC, 2019).
The U.S Department of Veteran Affairs (VA) and the Department of Defense (DoD) (2016) devised an evidence-based clinical practice guideline for the classification and management of concussions-mild traumatic brain injuries. Grounded in extensive research and updated every two years to ensure accuracy, the guideline provides a list of symptom criteria used to grade concussion severity, which is outlined below. See Table 1.4 for detailed classification of TBI severity.
- Mild TBI (Grade 1).Defined as either no loss of consciousness or a loss of consciousness lasting less than 30 minutes. There may be posttraumatic amnesia (PTA), which is loss of memory surrounding the trauma, may last up to 1 day (24 hours). An altered mental state such as feeling dazed, disoriented, or transient confusion may last up to 24 hours. It is estimated that up to 75% of TBIs are initially rated as mild. Glasgow Coma Scale (GCS) of 13-15.
- Moderate TBI (Grade 2).Defined as loss of consciousness lasting between 30 minutes and a few hours, up to 24 hours, followed by a few days or weeks of mental confusion. About 10-25% of TBIs are rated moderate. PTA can be apparent between 1 and 7 days. GCS score ranging from 9-12.
- Severe TBI (Grade 3). Defined as loss of consciousness for greater than 24 hours, either immediately after the injury or following a period of initial clarity. Less than 10% of all TBIs are rated severe. People who remain unconscious for a very long time may be described as in a coma or permanent vegetative state. GCS < 9.
The hallmark of mTBI treatment focuses on preventing secondary insults, called secondary prevention, and recognizing warning signs early (refer to Table 1.2). Therefore, education should be the central component of all concussion interventions (AANS, 2019). The mainstay treatment for the initial management of the acute symptoms resulting from a mTBI is complete cognitive and physical rest, as symptoms generally worsen when the metabolic trauma to the brain at the cellular level is challenged by stressful activity (Kamins & Giza, 2016).
Patients should be advised to take it easy for the first few days following an injury and limit physical and cognitive activities to avoid worsening of symptoms (Kamins & Giza, 2016). There is no definitive and quantifiable timeline for physical and cognitive rest following a mTBI due to the high variability in initial and future symptoms. While a rest period should be managed based on the individual patient and a consensus has not yet been achieved, data demonstrates that it is beneficial for the patient to have a minimum of a 24-48-hour initial rest period (Kamins & Giza, 2016). Resting the brain includes taking time off from sports as well as reducing visual stimulation by avoiding electronics, computers, video games, and bright screens (Martin, 2017). Patients should be counseled to avoid activities that place them at risk for another injury to the head and brain (Martin, 2017).
For headaches and other somatic symptoms, medications such as acetaminophen, nonsteroidal anti-inflammatory drugs, amitriptyline, or gabapentin may be used (Martin, 2017). However, it is strongly recommended that patients avoid medications that lower the seizure threshold (i.e. bupropion, traditional antipsychotic medications), or those the can cause confusion (i.e lithium, benzodiazepines) (Corrigan et al., 2019; Martin, 2017). Patients with a history of TBI can be more sensitive to side effects from medications, so it is critical these patients are monitored closely for toxicity and drug-drug interactions. Further, it is advised to limit quantities of medications with high risk for suicide, as the suicide rate is higher in this population (Corrigan et al., 2019; Stein et al., 2017).
Sleep is important for a concussion, as it allows the brain the opportunity to heal (AANS, 2019). For sleep dysregulation symptoms, sleep hygiene counseling and screening for anxiety, depression or post-traumatic stress disorder should be considered (AANS, 2019). Medications such as melatonin and trazadone may provide benefit (Stein et al., 2017). Cognitive disruptions and impairments must be monitored cautiously, and school and/or work accommodations are often necessary due to cognitive fatigue and concentration deficits (Tjong et al., 2017). Emotional symptoms should be monitored with extreme caution and patients should be screened for risk of self-harm (AANS, 2019). Anti-anxiety and anti-depressant medications may be used during this recovery period to alleviate some of these emotional symptoms (Martin, 2017).
Prognosis and Recovery
Epidemiological data acquired from the CDC (2019) and the TBIMS (2019) regarding the prognosis and recovery of individuals after mTBI, report that most will experience a full recovery within 3 weeks of injury. However, there are some individuals who endure persistent symptoms.
- Approximately 30% of patients experience symptoms one-month post injury.
- Approximately 10% of patients experience symptoms three-months post injury.
- Approximately 5% of patients experience symptoms one-year post injury (CDC, 2019).
Once symptoms have resolved, only then shouldpatients be reintroduced to daily activities (AANS, 2019). Return to work (or school) is generally advised as a symptom-guided and graded process that is unique to the individual patient, extent of deficits, prior concussions, and recovery of symptoms (Tiong et al., 2017). During the recovery period, it is important to avoid over-exertion and to avoid re-injury, so patients should be counseled on resuming their full amount of daily activities over time, as a gradual transition to preserve function and avoid overstimulation (AANS, 2019). Abrupt re-entry to normal activities, such as work, school, or sports, may induce cognitive fatigue, overwhelm the brain, and lead to a setback in healing with recurrence of symptoms (Kamins & Gizo, 2016).Before returning to sports, athletes recovering from concussion must be symptom-free at rest and after physical and mental exertion (Stein et al., 2017).
The length of time the patient should refrain from strenuous activity is based on the grade of the concussion, history of prior concussions, and severity of symptoms. Patients with a history of prior concussions have longer restrictions (Stein et al., 2017). Recovery may be slower among older adults, younger children, and adolescents. Those who have had a TBI in the past are at higher risk for impaired recovery, post-concussion syndrome, and long-term deficits (Kapadia, Scheid, Fine, & Zoffness, 2019).Additional factors that may potentially delay recovery time include: preexisting neurological or psychiatric health conditions, learning disabilities or difficulties, family, social, psychosocial stressors, and alcohol or other CNS depressant drugs, which can slow recovery and put patients at risk of further injury (CDC, 2019).
Post-Concussion Syndrome (PCS)
Post-Concussion Syndrome (PCS) refers to a collection of symptoms following a concussion that persist for a prolonged period of time despite an adequate rest period (Kapadia et al., 2019). These symptoms are similar to all of the symptoms of a concussion, but instead of improving with time and rest, they persist or worsen, and are refractory to interventions (Kamins & Giza, 2016). PCS is a complex pathophysiologic process, and there is not currently a consensus on the duration of symptoms needed to make the diagnosis. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines the condition as concussive symptoms more than 3 months (Kapadia et al., 2019). PCSoccurs most commonly in patients with a history of multiple concussions and treatment is most often a matter of resting and allowing the brain’s natural recovery process the time to heal the damage caused by a concussion (Tiong et al., 2017). However, given the complexity of the diagnosis, those who are suspected of PCS should be referred to a specialist in the area of traumatic brain injuries and concussions. There is no single treatment that is effective in all cases, but clinicians may prescribe pharmacologic or other active therapies to help alleviate specific symptoms (AANS, 2019).
Concussion prevention primarily focuses on general safety, such as wearing properly fitting helmets, appropriate installation of car and booster seats, habitually wearing a seatbelt, wearing protective gear during contact sports, and engaging in safe sport cultures (CDC, 2019). In addition, avoiding risky behaviors that are potentially hazardous, such as engaging in violent behavior or driving under the influence of alcohol or drugs (Bramley, Hong, Zacko, Royer, Silvis, 2016).
Chronic Traumatic Encephalopathy
Chronic traumatic encephalopathy (CTE) is a progressive degenerative brain disease associated with repetitive head trauma most commonly found in military veterans or professional athletes (Chadehumbe, 2016). In CTE, a protein called Tau forms clumps that slowly spread throughout the brain, killing brain cells, and causing brain function to gradually deteriorate over time (Tharmaratnam et al., 2018).Currently, CTE can only be confirmed post-mortem, but has become a topic of interest based on media coverage surrounding professional athletes, mental health, and suicide (Chadehumbe, 2016). Early symptoms may only affect a patient's mood and behavior, but the symptoms are progressive and heighten over time. Some common changes seen include impulse control problems, aggression, depression, and paranoia. As the disease progresses, some patients may experience problems with thinking and memory, including memory loss, confusion, impaired judgment, and eventually progressive dementia (Tharmaratnam et al., 2018).
The CDC has produced 19 sets of recommendations that are aimed for nurses and providers practicing in primary care, inpatient, outpatient and emergency settings through the HEADS UP Program.The CDC also offers customized education materials for healthcare professionals, parents, coaches, school officials, and so forth (CDC, 2019). For more information, please refer to the CDC website and search for “HEADS UP” Program.
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