Management Of Mild Traumatic Brain Injury In The Emergency Department (Trauma CME)

Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal Of The Literature
   1. Definitions
5. Epidemiology
   1. Morbidity And Mortality
6. Pathophysiology
7. Prehospital Care
   1. Transport
8. Emergency Department Management
   1. Initial Evaluation
   2. History
   3. Physical Examination
      1. Neurological Examination
         • Glasgow Coma Scale Score
         • Cognitive Examination
         • Pupillary Reflexes
         • Motor And Balance Testing
9. Diagnostic Testing
   1. Laboratory And Bedside Studies
   2. Radiography
      1. Plain Skull Radiography
      2. Computed Tomography
10. Postconcussive Syndrome
11. Sports-Related Concussion
12. Controversies And Cutting Edge
    1. Biomarkers
    2. Diffusion-Weighted Imaging
    3. Neuropsychological And Sideline Testing
13. Disposition
14. Key Points For Evaluating And Treating Mild Traumatic Brain Injury
15. Summary
    1. Areas In Need Of Future Research
16. Risk Management Pitfalls For Mild Traumatic Brain Injury
17. Cost-Effective Strategies For Mild Traumatic Brain Injury
18. Case Conclusions
19. Clinical Pathway For Evaluating The Adult With Mild Traumatic Brain Injury
20. Clinical Pathway For Evaluating The Child With Mild Traumatic Brain Injury
21. Tables and Figures
    1. Table 1. Major Guidelines On Mild Traumatic Brain Injury
    2. Table 2. Glasgow Coma Scale Scoring
    3. Table 3. Components Of The Sports Concussion Assessment Tool-2 (SCAT2)
    4. Table 4. Clinical Decision Rules In Mild Traumatic Brain Injury In Adults
    5. Table 5. Pecarn Clinical Decision Ruke For Children With mild Traumatic Brain Injury
    6. Table 6. Symptoms Seen In Postconcussive Syndrome
    7. Table 7. Indications For Computed Tomography In Mild Traumatic Brain Injury
    8. Figure 1. Diffusion-Weighted Magnetic Resonance Imaging Showing Frontal Injury
22. References

Abstract

With over 1.7 million people in the United States seeking medical attention for head injury each year, emergency clinicians are challenged daily to screen quickly for the small subset of patients who harbor a potentially lethal intracranial lesion while minimizing excessive cost, unnecessary diagnostic testing, radiation exposure, and admissions. Whether working at a small, rural hospital or a large inner-city public hospital, emergency clinicians play a critical role in the diagnosis and management of mild traumatic brain injury. This review assesses the burgeoning research in the field and reviews current clinical guidelines and decision rules on mild traumatic brain injury, addressing the concept of serial examinations to identify clinically significant intracranial injury, the approach to pediatric and elderly patients, and the management of patients who are on anticoagulants or antiplatelet agents or have bleeding disorders. The evidence on sports-related concussion and postconcussive syndrome is reviewed, and tools for assessments and discharge are included.

Case Presentations

It’s 8 PM and you are just getting into the groove of your first in a series of several night shifts. After picking up your fourth head injury chart, you think to yourself, “Good grief, are we having a sale on head injury tonight?” Your patients are:

• A 16-year-old boy brought in by his parents after head-butting another player during a soccer game. He was confused for several minutes and now has a headache. His coach told his parents that he had a concussion and should go to the ER to be checked out before he can return to play.
• A 38-year-old woman who was in a low-speed motor vehicle crash. She states that she “blacked out” for a few seconds but feels fine now.
• A 2-month-old brought in by her parents with a bump on her head. They said the babysitter told them the baby rolled off the bed while she was changing her diaper.
• A well-known (to you) alcoholic brought in by the police, intoxicated, with an abrasion on his forehead. He has no idea how he hit his head and is asking for something to eat.

These are 4 cases of what appear to be minor injuries, although you know there is the chance that any of the patients may be harboring a neurosurgical lesion and that all 4 are at risk for sequelae. In your mind, you systematically go through the high-return components of the physical exam of a head-injured patient, the indications for neuroimaging in the ED, and the information needed at discharge to prepare the patients and their families for what might lie ahead. The medical student working with you is very impressed with the complexity of managing these cases, which he thought were so straightforward.

Introduction

Minor head injury, mild traumatic brain injury (TBI, also known as MTBI), and concussion are terms that are often used interchangeably. Regardless of the variation in nomenclature, emergency clinicians can expect to see a number of patients each shift who have sustained some sort of blunt trauma to the head. The clinical approach to these patients varies widely, and, despite the availability of clinical guidelines, most patients will undergo computed tomography (CT) imaging, and the majority will be interpreted as normal. The challenge for emergency clinicians is to quickly screen for the small subset of patients who harbor a potentially lethal intracranial lesion while minimizing excessive costs, admissions, and unnecessary diagnostic testing. Emergency clinicians must accurately document a neurologic baseline for serial examinations and provide discharge instructions that educate patients and families about the potential sequelae of head injury no matter how minor the injury may appear to be.

Further challenges include the rapidly evolving milieu of head injury treatment in the sports arena, with all but 2 states having active or pending laws on return to play for youth sports and full elimination of any same-day return to play after concussive events.¹ Furthermore, with up to 50% of nonactive military personnel seeking care outside of the Veterans Health Administration system,² emergency clinicians can expect to provide care for the increasing numbers of military personnel returning to the United States with postconcussive symptoms. Called the “signature’”injury of the Iraq and Afghanistan Wars, military-related mild TBI has affected close to 200,000 soldiers to date,^3,4 with up to 30% suffering continued postconcussive symptoms.⁵

Critical Appraisal Of The Literature

Appraising the literature is very challenging due to the lack of uniformity—and often impassioned disagreement—regarding the definition of the terms used to describe these injuries. Moreover, studies often lack consistency in the timing of injury assessments, suffer from selection bias, and have conflicting outcome measures. The literature review was performed using PubMed and Ovid MEDLINE^® searches for articles on TBI published between 1966 and 2012. Keywords included traumatic brain injury, concussion, head injury, MTBI, neuroimaging, postconcussive syndrome, sports, and second impact syndrome. The articles obtained from these searches provided content and background for further manual literature searches. Over 650 articles were reviewed, and 158 of these are included here for the reader’s reference.

Additionally, major published guidelines regarding mild TBI were evaluated. These included guidelines published by the Centers for Disease Control and Prevention (CDC), the Brain Trauma Foundation, the American College of Emergency Physicians (ACEP), the American Academy of Neurology, the American Academy of Pediatrics, the Advanced Trauma Life Support^® (ATLS^®) course, and the Eastern Association for the Surgery of Trauma. Website addresses for several guidelines are provided in Table 1.

Risk Management Pitfalls For Mild Traumatic Brain Injury

1. “The GCS score was normal. How can he have a head bleed?”
   Even in patients with a GCS score of 15, there is a small—but definite—risk for an intracranial lesion. About 6% to 8% of patients with mild TBI and a normal GCS have ICI on CT, and less than 1% will require neurosurgical intervention.^13,20,22
2. “But I told the patient everything at discharge.”
   Patients discharged from the ED after mild TBI can be expected to recall no more than 30% to 50% of verbal instructions, and a significant number will suffer from both short-term and long-term postconcussive symptoms.^8,14 This holds true even for those patients who appear completely neurologically intact. Consequently, all discharge instructions should not only be written down, but also told to a responsible third party.
3. “But the skull films showed no fracture.”
   Numerous studies have demonstrated the low sensitivity of skull films for predicting intracranial lesions. Though the presence of a fracture on a skull film increases the incidence of a traumatic intracranial lesion, the absence of a visible fracture does not decrease the incidence of an intracranial lesion. CT with bone windows is the imaging strategy of choice for patients with suspected TBI.
4. “The babysitter initially said that the baby fell down the steps, and then changed her story and said the baby fell off the sofa.”
   Child abuse is a frequently reported cause of TBI in infants. Emergency clinicians should be on their guard and recall that an inconsistent history is often associated with child abuse.³⁹ When in doubt, it is best to err on the side of caution and involve the proper child protective services.
5. “But the CT was negative.”
   CT is an excellent test for identifying lesions in need of neurosurgical intervention, but it is not very good at identifying brain stem lesions, basilar skull fractures, or nonhemorrhagic injuries. In fact, about 25% of focal axonal injuries,⁶⁹ 50% of brain stem lesions,⁷⁰ and 30% of basilar skull fractures are missed on CT.⁷¹ These injuries typically involve a great deal of energy and are therefore not commonly found in a patient with mild TBI or found in isolation.¹³⁸ It is extremely rare for an initially undetected lesion on CT to evolve into a lesion that requires neurosurgical intervention.¹³⁹ Patients and families should be given discharge instructions that describe symptoms that require a repeat visit to the ED.
6. “The patient is malingering. His CT was negative, and the neurologic examination was normal.”
   Many patients diagnosed with mild TBI have deficits on cognitive testing despite a normal CT. Most of these deficits resolve within 3 months of the injury, but some do not. It is very stressful for patients with persistent symptoms that do not seem to be supported by objective evidence. Follow-up with a neurologist can be very helpful to determine the need for further neuroimaging or neuropsychological testing.
7. “The coach asked me if he could play in the tournament tomorrow.”
   There is no longer any role for same-day return to play, and the assessment for return to play involves the individual evaluation of the player by his or her primary care or sports medicine physician with consideration to the severity of concussion, past injuries, and expected future impact injuries. Discharge instructions must include both physical and cognitive rest until cleared by the player’s physician.
8. “I thought the patient was just drunk.”
   Alcohol users are at increased risk for TBI, and evaluation is made difficult by their intoxication. These patients require serial neurologic evaluations, and if there are any associated high-risk criteria, a CT is indicated.
9. “He didn’t get knocked out. How could he have a subdural hematoma?”
   In many cases of mild TBI, there will be no loss of consciousness, and only about 10% of sports TBI is associated with loss of consciousness. A period of unconsciousness or amnesia to the event is not required for ICI, and the absence of loss of consciousness is not protective against ICI or future symptoms of postconcussive syndrome.
10. “I know he was on warfarin, but his CT was normal, so I sent him home.”
    Delayed hemorrhage is a rare, but important, concern in anticoagulated patients.^114,115 All patients on anticoagulants must be educated about the risk of delayed hemorrhage and instructed to return for a repeat CT in the setting of any new or worsening symptoms.

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study will be included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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