Assessment of traumatic brain injury, acute
Summary
Definitions
Traumatic brain injury (TBI) is a disruption of the normal function of the brain caused by a head injury.[1]Centers for Disease Control and Prevention, US Department of Health and Human Services. Surveillance report of traumatic brain injury-related emergency department visits, hospitalizations, and deaths - United States, 2014. 2019 [internet publication]. https://www.cdc.gov/traumaticbraininjury/pdf/TBI-Surveillance-Report-508.pdf Blunt trauma, penetrating injuries, and blast injuries may all cause TBI. Not all head injuries cause TBI. TBI can be classified as mild, moderate, or severe, typically based on the Glasgow Coma Scale (GCS) score and/or neurobehavioural deficits after the injury.
The term 'concussion' is often used interchangeably with mild TBI. Both the Centers for Disease Control and Prevention and the World Health Organization agree that mild TBI is due to a blunt or mechanical force that results in: some type of transient confusion, disorientation or loss of consciousness lasting not more than 30 minutes; possibly associated with transient neurobehavioural deficits; and a GCS no worse than 13.[2]McCrea HJ, Perrine K, Niogi S, et al. Concussion in sports. Sports Health. 2013 Mar;5(2):160-4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3658375/ http://www.ncbi.nlm.nih.gov/pubmed/24427385?tool=bestpractice.com CDC: heads up external link opens in a new window However, there is ongoing debate about whether patients with a GCS of 13 should instead be classified as having moderate TBI.
Classification
TBI can be classified in numerous ways, including type, severity, location, mechanism of injury, and physiological response to injury. This heterogeneity is considered to be one of the most significant barriers to establishing effective therapeutic interventions in TBI.[3]Saatman KE, Duhaime AC, Bullock R, et al; Workshop Scientific Team and Advisory Panel Members. Classification of traumatic brain injury for targeted therapies. J Neurotrauma. 2008 Jul;25(7):719-38. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2721779/ http://www.ncbi.nlm.nih.gov/pubmed/18627252?tool=bestpractice.com Efforts in the US and the UK to standardise the naming, definitions, and classification of TBI subgroups have the potential to reduce the variability in data coding and improve the quality of data gathering in TBI research.[4]Adelson PD, Pineda J, Bell MJ, et al. Common data elements for pediatric traumatic brain injury: recommendations from the working group on demographics and clinical assessment. J Neurotrauma. 2012 Mar 1;29(4):639-53. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3289844/ http://www.ncbi.nlm.nih.gov/pubmed/21939389?tool=bestpractice.com [5]Ardolino A, Sleat G, Willett K. Outcome measurements in major trauma - results of a consensus meeting. Injury. 2012 Oct;43(10):1662-6. http://www.ncbi.nlm.nih.gov/pubmed/22695320?tool=bestpractice.com [6]Berger RP, Beers SR, Papa L, et al. Common data elements for pediatric traumatic brain injury: recommendations from the biospecimens and biomarkers workgroup. J Neurotrauma. 2012 Mar 1;29(4):672-7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3289842/ http://www.ncbi.nlm.nih.gov/pubmed/22106839?tool=bestpractice.com
Classification by clinical severity
The GCS has been used extensively to classify TBI into levels of severity and prognosis.[7]Carney N, Totten AM, O'Reilly C, et al. Guidelines for the management of severe traumatic brain injury, fourth edition. Neurosurgery. 2017 Jan 1;80(1):6-15. https://braintrauma.org/uploads/03/12/Guidelines_for_Management_of_Severe_TBI_4th_Edition.pdf http://www.ncbi.nlm.nih.gov/pubmed/27654000?tool=bestpractice.com [8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com After traumatic brain injury, there is an inverse relationship between the GCS score and the incidence of positive findings on computed tomography (CT); in fact, the rate of intracranial injury (ICI) and need for neurosurgical intervention doubles when the GCS drops from 15 to 14.[9]Smits M, Dippel DW, Steyerberg EW, et al. Predicting intracranial traumatic findings on computed tomography in patients with minor head injury: the CHIP prediction rule. Ann Intern Med. 2007 Mar 20;146(6):397-405. http://www.ncbi.nlm.nih.gov/pubmed/17371884?tool=bestpractice.com [10]Ibañez J, Arikan F, Pedraza S, et al. Reliability of clinical guidelines in the detection of patients at risk following mild head injury: results of a prospective study. J Neurosurg. 2004 May;100(5):825-34. http://www.ncbi.nlm.nih.gov/pubmed/15137601?tool=bestpractice.com
Mild TBI: GCS 13-15; mortality 0.1%
Moderate TBI: GCS 9-12; mortality 10%
Severe TBI: GCS <9; mortality 40%.
Many clinicians recommend that patients with a GCS of 13 be classified as moderate instead of mild, due to the higher incidence of ICI and poor outcomes in these patients.[11]Türedi S, Hasanbasoglu A, Gunduz A, et al. Clinical decision instruments for CT scan in minor head trauma. J Emerg Med. 2008 Apr;34(3):253-9. http://www.ncbi.nlm.nih.gov/pubmed/18180129?tool=bestpractice.com [12]Pearson WS, Ovalle F Jr, Faul M, et al. A review of traumatic brain injury trauma center visits meeting physiologic criteria from the american college of surgeons committee on trauma/centers for disease control and prevention field triage guidelines. Prehosp Emerg Care. 2012 Jul-Sep;16(3):323-8. http://www.ncbi.nlm.nih.gov/pubmed/22548387?tool=bestpractice.com [13]Mena JH, Sanchez AI, Rubiano AM, et al. Effect of the modified Glasgow Coma Scale score criteria for mild traumatic brain injury on mortality prediction: comparing classic and modified Glasgow Coma Scale score model scores of 13. J Trauma. 2011 Nov;71(5):1185-92; discussion 1193. http://www.ncbi.nlm.nih.gov/pubmed/22071923?tool=bestpractice.com Clinical guidelines in Australia recognise the increased morbidity associated with a GCS of 13, and limit the classification of mild TBI to those patients with a GCS of 14 or 15.[14]New South Wales Ministry of Health. Closed head injury in adults - initial management. Feb 2012 [internet publication]. http://www1.health.nsw.gov.au/pds/ActivePDSDocuments/PD2012_013.pdf
The Mayo classification system for TBI classifies patients with TBI into definite, probable, and possible, based on the patient’s clinical and CT findings.[15]Malec JF, Brown AW, Leibson CL, et al. The Mayo classification system for traumatic brain injury severity. J Neurotrauma. 2007 Sep;24(9):1417-24. http://www.ncbi.nlm.nih.gov/pubmed/17892404?tool=bestpractice.com
Classification by broad aetiology
Blunt TBI: occurs when external mechanical force leads to rapid acceleration or deceleration with brain impact. It is typically found in the setting of motor vehicle-related injury, falls, crush injuries, or physical altercations.
Penetrating TBI: occurs when an object pierces the skull and breaches the dura mater, seen commonly in gunshot and stab wounds.
Blast TBI: commonly occurs after bombings and warfare, due to a combination of contact and inertial forces, overpressure, and acoustic waves.[16]Ling G, Bandak F, Armonda R, et al. Explosive blast neurotrauma. J Neurotrauma. 2009 Jun;26(6):815-25. http://www.ncbi.nlm.nih.gov/pubmed/19397423?tool=bestpractice.com
Classification by area of involvement
TBI can be classified by area involved, as in diffuse or focal, although the two types frequently coexist.
Diffuse brain injury includes diffuse axonal injury (DAI), hypoxic brain injury, diffuse cerebral oedema, or diffuse vascular injury.[17]Maas AI, Stocchetti N, Bullock R. Moderate and severe traumatic brain injury in adults. Lancet Neurol. 2008 Aug;7(8):728-41. http://www.ncbi.nlm.nih.gov/pubmed/18635021?tool=bestpractice.com
Focal injury includes specific lesions such as contusions, intracranial haematomas, infarctions, axonal tears, cranial nerve avulsions, and skull fractures.[17]Maas AI, Stocchetti N, Bullock R. Moderate and severe traumatic brain injury in adults. Lancet Neurol. 2008 Aug;7(8):728-41. http://www.ncbi.nlm.nih.gov/pubmed/18635021?tool=bestpractice.com
Classification by injury progression
Primary injury is due to the immediate mechanical force, whether blunt, penetrating, or blast, and may include the following:
Skull fracture
Contusion
Haematoma
Subarachnoid or focal haemorrhage
Axonal shear or laceration.
Secondary injury refers to the evolving pathophysiological consequences of the primary injury and encompasses a multitude of complex neurobiological cascades altered or initiated at a cellular level following the primary injury, and may include the following:[17]Maas AI, Stocchetti N, Bullock R. Moderate and severe traumatic brain injury in adults. Lancet Neurol. 2008 Aug;7(8):728-41. http://www.ncbi.nlm.nih.gov/pubmed/18635021?tool=bestpractice.com
Cerebral oedema
Increased intracranial pressure
Haemorrhage
Seizures
Ischaemia
Infection.
Epidemiology of TBI
TBI is a substantial cause of morbidity and mortality, leading to more than 2.5 million accident and emergency department visits annually in the US, an increase from 1.6 million in 2006, and more than 1.4 million in the UK.[1]Centers for Disease Control and Prevention, US Department of Health and Human Services. Surveillance report of traumatic brain injury-related emergency department visits, hospitalizations, and deaths - United States, 2014. 2019 [internet publication]. https://www.cdc.gov/traumaticbraininjury/pdf/TBI-Surveillance-Report-508.pdf [18]National Institute for Health and Care Excellence. Head injury: assessment and early management. Sep 2019 [internet publication]. http://www.nice.org.uk/Guidance/CG176 The burden of disability and death due to TBI is higher in low- and middle-income countries compared with high-income countries.[19]Maas AIR, Menon DK, Adelson PD, et al; InTBIR Participants and Investigators. Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research. Lancet Neurol. 2017 Dec;16(12):987-1048. http://www.ncbi.nlm.nih.gov/pubmed/29122524?tool=bestpractice.com
Around 80% of patients with TBI sustain a minor head injury, and are treated and released without hospital admission or intervention, other than diagnostic imaging.[20]Pandor A, Goodacre S, Harnan S, et al. Diagnostic management strategies for adults and children with minor head injury: a systematic review and an economic evaluation. Health Technol Assess. 2011 Aug;15(27):1-202. https://www.ncbi.nlm.nih.gov/books/NBK100016/ http://www.ncbi.nlm.nih.gov/pubmed/21806873?tool=bestpractice.com About 10% have injuries that require hospitalisation and about 2% die.[1]Centers for Disease Control and Prevention, US Department of Health and Human Services. Surveillance report of traumatic brain injury-related emergency department visits, hospitalizations, and deaths - United States, 2014. 2019 [internet publication]. https://www.cdc.gov/traumaticbraininjury/pdf/TBI-Surveillance-Report-508.pdf
TBI is the most common cause of death in people under the age of 25. It most frequently occurs in very young children (age 0 to 4 years) and in adolescence and young adulthood (age 15 to 24 years), with a subsequent peak in incidence in older adults (over age 65). Older age comprises the group with the highest rates of TBI-related hospitalisations and deaths.[1]Centers for Disease Control and Prevention, US Department of Health and Human Services. Surveillance report of traumatic brain injury-related emergency department visits, hospitalizations, and deaths - United States, 2014. 2019 [internet publication]. https://www.cdc.gov/traumaticbraininjury/pdf/TBI-Surveillance-Report-508.pdf
Males are over-represented by 3:1 in all subgroups of TBI. Neurosurgical intervention (craniotomy, elevation of skull fracture, increased intracranial pressure monitor, or ventriculostomy) is required in about 40% of patients with severe TBI, about 10% of patient with moderate TBI, and about 1% of patients with mild TBI.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [21]Bullock MR, Chesnut R, Ghajar J, et al; Surgical Management of Traumatic Brain Injury Author Group. Surgical management of acute subdural hematomas. Neurosurgery. 2006 Mar;58(3 suppl):S16-24. http://www.ncbi.nlm.nih.gov/pubmed/16710968?tool=bestpractice.com In 2017, 15% of high school students in the US reported at least one sports-related concussion in the past year.[22]DePadilla L, Miller GF, Jones SE, et al. Self-reported concussions from playing a sport or being physically active among high school students - United States, 2017. MMWR Morb Mortal Wkly Rep. 2018 Jun 22;67(24):682-5. https://www.cdc.gov/mmwr/volumes/67/wr/mm6724a3.htm?s_cid=mm6724a3_w http://www.ncbi.nlm.nih.gov/pubmed/29927909?tool=bestpractice.com Approximately 30% of children and adults experience persistent post-concussive symptoms lasting more than 30 days after injury.[23]Zemek R, Barrowman N, Freedman SB, et al. Clinical risk score for persistent postconcussion symptoms among children with acute concussion in the ED. JAMA. 2016 Mar 8;315(10):1014-25. http://www.ncbi.nlm.nih.gov/pubmed/26954410?tool=bestpractice.com [24]de Koning ME, Scheenen ME, van der Horn HJ, et al. Non-hospitalized patients with mild traumatic brain injury: the forgotten minority. J Neurotrauma. 2017 Jan 1;34(1):257-61. http://www.ncbi.nlm.nih.gov/pubmed/27029852?tool=bestpractice.com
Epidemiology of specific injuries
Most patients have a combination of injuries.
Traumatic subarachnoid haemorrhage (SAH) is one of the most common CT findings in TBI, occurring in about 30% to 40% of patients with moderate to severe TBI, and 5% of patients with mild TBI.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [25]Steyerberg EW, Mushkudiani N, Perel P, et al. Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics. PLoS Med. 2008 Aug 5;5(8):e165. http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050165 http://www.ncbi.nlm.nih.gov/pubmed/18684008?tool=bestpractice.com [26]Roberts I, Yates D, Sandercock P, et al; CRASH trial collaborators. Effect of intravenous corticosteroids on death within 14 days in 10008 adults with clinically significant head injury (MRC CRASH trial): randomised placebo-controlled trial. Lancet. 2004 Oct 9-15;364(9442):1321-8. http://www.ncbi.nlm.nih.gov/pubmed/15474134?tool=bestpractice.com SAH is frequently associated with other injuries. SAH is associated with a poorer outcome in patients with moderate or severe TBI, although it is unclear whether the SAH is simply a marker of severity of injury, or if the poorer outcomes are due to subsequent vasospasm.[27]Kramer DR, Winer JL, Pease BA, et al. Cerebral vasospasm in traumatic brain injury. Neurol Res Int. 2013;2013:415813. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703898/ http://www.ncbi.nlm.nih.gov/pubmed/23862062?tool=bestpractice.com
Subdural haematomas (SDH) are the most common type of mass lesion in TBI, seen in about 20% of patients with moderate to severe TBI, and in about 30% of fatal TBI. SDH occur in only 3% of patients with mild TBI. SDH that lead to hospitalisations or deaths are most commonly secondary to motor vehicle-related injury in younger adults, and falls in older adults.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [21]Bullock MR, Chesnut R, Ghajar J, et al; Surgical Management of Traumatic Brain Injury Author Group. Surgical management of acute subdural hematomas. Neurosurgery. 2006 Mar;58(3 suppl):S16-24. http://www.ncbi.nlm.nih.gov/pubmed/16710968?tool=bestpractice.com
Epidural haematomas (EDH) are seen in about 10% of patients with moderate to severe TBI and about 1% of patients with mild TBI. The incidence of EDH is highest among adolescents and young adults, most commonly between 20 and 30 years of age. Most cases of EDH are caused by traffic accidents, falls, and assaults.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [25]Steyerberg EW, Mushkudiani N, Perel P, et al. Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics. PLoS Med. 2008 Aug 5;5(8):e165. http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050165 http://www.ncbi.nlm.nih.gov/pubmed/18684008?tool=bestpractice.com
Contusions occur in 20% to 30% of patients with moderate to severe TBI, and 6% of patients with mild TBI.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [26]Roberts I, Yates D, Sandercock P, et al; CRASH trial collaborators. Effect of intravenous corticosteroids on death within 14 days in 10008 adults with clinically significant head injury (MRC CRASH trial): randomised placebo-controlled trial. Lancet. 2004 Oct 9-15;364(9442):1321-8. http://www.ncbi.nlm.nih.gov/pubmed/15474134?tool=bestpractice.com [28]Iaccarino C, Schiavi P, Picetti E, et al. Patients with brain contusions: predictors of outcome and relationship between radiological and clinical evolution. J Neurosurg. 2014 Apr;120(4):908-18. http://www.ncbi.nlm.nih.gov/pubmed/24506250?tool=bestpractice.com
Intracerebral haematomas occur in 10% to 30% of patients with moderate to severe TBI, and <1% of patients with mild TBI.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com [17]Maas AI, Stocchetti N, Bullock R. Moderate and severe traumatic brain injury in adults. Lancet Neurol. 2008 Aug;7(8):728-41. http://www.ncbi.nlm.nih.gov/pubmed/18635021?tool=bestpractice.com
Axonal injury is probably present in a majority proportion of patients with TBI to some degree, although low grade axonal injury is usually microscopic and not detected by CT. Diffuse axonal injury (DAI) is thought to be present to some degree in all TBI-related fatalities and those resulting in a persistent vegetative state. The presence of DAI increases the likelihood of a poor outcome.[29]van Eijck MM, Schoonman GG, van der Naalt J, et al. Diffuse axonal injury after traumatic brain injury is a prognostic factor for functional outcome: a systematic review and meta-analysis. Brain Inj. 2018;32(4):395-402. http://www.ncbi.nlm.nih.gov/pubmed/29381396?tool=bestpractice.com The initial CT is normal in 50% to 80% of patients ultimately diagnosed with DAI, but magnetic resonance imaging shows evidence of axonal injury in 70% of patients with moderate to severe TBI.[30]Skandsen T, Kvistad KA, Solheim O, et al. Prevalence and impact of diffuse axonal injury in patients with moderate and severe head injury: a cohort study of early magnetic resonance imaging findings and 1-year outcome. J Neurosurg. 2010 Sep;113(3):556-63. http://www.ncbi.nlm.nih.gov/pubmed/19852541?tool=bestpractice.com
Skull fractures occur in about 5% of patients with mild TBI and up to 50% of those with severe TBI. Most skull fractures are due to falls, assaults, or motor vehicle-related injuries. The most common fractures are simple linear fractures, comprising >50% of all skull fractures. Less than 1% of patients with mild TBI have a depressed skull fracture.[8]Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT head rule for patients with minor head injury. Lancet. 2001;357(9266):1391-6. http://www.ncbi.nlm.nih.gov/pubmed/11356436?tool=bestpractice.com
Penetrating injuries are classified as high- or low-velocity, and may be self-inflicted, non-intentional, or related to an assault. A single gunshot wound to the head has 50% mortality.[31]Cripps MW, Ereso AQ, Sadjadi J, et al. The number of gunshot wounds does not predict injury severity and mortality. Am Surg. 2009 Jan;75(1):44-8. http://www.ncbi.nlm.nih.gov/pubmed/19213396?tool=bestpractice.com
Blast injuries are a leading cause of TBI in active duty military personnel in war zones, accounting for about 60% of all severe TBI.[32]DuBose JJ, Barmparas G, Inaba K, et al. Isolated severe traumatic brain injuries sustained during combat operations: demographics, mortality outcomes, and lessons to be learned from contrasts to civilian counterparts. J Trauma. 2011 Jan;70(1):11-8. http://www.ncbi.nlm.nih.gov/pubmed/21217475?tool=bestpractice.com
Differentials
Common
- Skull fracture (excl. base of skull)
- Base of skull fracture
- Cerebral contusion
- Intracerebral haemorrhage
- Subdural haematoma
- Epidural haematoma
- Intraventricular haemorrhage
- Traumatic subarachnoid haemorrhage
- Penetrating injuries
- Diffuse axonal injury
- Mild traumatic brain injury
Contributors
AuthorsVIEW ALL
Albert J. Lauro Professor of Medicine/Emergency Medicine
Clinical Professor Medicine/Emergency Medicine
Section of Emergency Medicine
Louisiana State University Health Science Center
New Orleans
LA
Disclosures
MJH is an author of a reference cited in this topic.
Dr Micelle J. Haydel would like to gratefully acknowledge Dr Victoria E. Johnson, Dr Marek Ma, Dr Nathan Ranalli, and Dr Douglas H. Smith, previous contributors to this topic.
Disclosures
VEJ, MM, NR, and DHS declare that they have no competing interests.
Peer reviewersVIEW ALL
Director of Research
Department of Emergency Medicine
Emory University
Atlanta
GA
Disclosures
DWW declares that he has no competing interests.
Senior Lecturer In Neurology
Imperial College
London
UK
Disclosures
DS declares that he has no competing interests.
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