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{{Concussion}}
{{Concussion}}
==Definitions==
No single definition of concussion, mild head injury,<ref name="SatzZaucha">
{{
cite journal |author=Satz P, Zaucha K, McCleary C, Light R, Asarnow R, Becker D |title=Mild head injury in children and adolescents: A review of studies (1970–1995) |journal=Psychological Bulletin |volume=122 |issue=2 |pages=107–131 |year=1997 |pmid=9283296 |doi=
}}</ref> or mild traumatic brain injury is universally accepted, though a variety of definitions have been offered.<ref name="ComperBisschop">
{{
cite journal |author=Comper P, Bisschop SM, Carnide N, Tricco A |title=A systematic review of treatments for mild traumatic brain injury |journal=Brain Injury |volume=19 |issue=11 |pages=863–880 |year=2005 |pmid=16296570 |doi=10.1080-0269050400025042 |issn=0269-9052
}}
</ref>  In 2001, the first International Symposium on Concussion in Sport was organized by the International Olympic Committee Medical Commission and other sports federations.<ref name="aubry"/> A group of experts called the Concussion in Sport Group met there and defined concussion as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces."<ref name="canturc06">
{{
cite journal |author=Cantu RC |date=2006 |url=http://www.aans.org/education/journal/neurosurgical/Oct06/21-4-3-1067.pdf |format=PDF |title=An overview of concussion consensus statements since 2000 |journal=Neurosurgical Focus |volume=21 |issue=4:E3 |pages=1–6
}}<!-- No PMID found -->
</ref>  They agreed that concussion typically involves temporary impairment of neurological function which quickly resolves by itself, and that [[neuroimaging]] normally shows no gross structural changes to the brain as the result of the condition.<ref name="AndersonT"/> 
According to the classic definition, no structural brain damage occurs in concussion;<ref>
{{
cite journal |author=Parkinson D |year=1999 |title=Concussion confusion |journal=Critical Reviews in Neurosurgery |volume=9 |issue=6 |pages=335–339 |issn=1433-0377 |doi=10.1007/s003290050153
}}<!--Not indexed on Pubmed--></ref> it is a functional state, meaning that symptoms are caused primarily by temporary [[biochemistry|biochemical]] changes in [[neuron]]s, taking place for example at their [[cell membrane]]s and [[synapse]]s.<ref name="AndersonT"/> However, in recent years researchers have included [[injury|injuries]] in which structural damage does occur under the rubric of concussion.  According to the [[National Institute for Health and Clinical Excellence]] definition, concussion may involve a physiological or physical disruption in the brain's [[chemical synapse|synapse]]s.<ref name="NICE">
{{
cite web|url=http://www.nice.org.uk/nicemedia/pdf/CG56guidance.pdf|format=PDF |publisher=National Institute for Health and Clinical Excellence |title=Head Injury: Triage, Assessment, Investigation and Early Management of Head Injury in Infants, Children and Adults |isbn=0-9549760-5-3 |date=September 2007 |accessdate=2008-01-26
}}</ref>
Definitions of mild traumatic brain injury (MTBI) have been inconsistent since the 1970s, but the [[World Health Organization]]'s [[ICD-10|International Statistical Classification of Diseases and Related Health Problems]] (ICD-10) described MTBI-related conditions in 1992, providing a consistent, authoritative definition across specialties.<ref name="Petchprapai07"/> In 1993, the American Congress of Rehabilitation Medicine defined MTBI as 30&nbsp;minutes or fewer of [[loss of consciousness]] (LOC), 24&nbsp;hours or fewer of [[post-traumatic amnesia]] (PTA), and  a [[Glasgow Coma Scale]] (GCS) score of at least 13.<ref name="Kushner98">
{{
cite journal |author=Kushner D |title=Mild Traumatic brain injury: Toward understanding manifestations and treatment |journal=Archives of Internal Medicine |volume=158 |issue=15 |pages=1617–1624 |year=1998 |pmid=9701095 |doi= |url=http://archinte.highwire.org/cgi/content/full/158/15/1617
}}</ref> In 1994, the [[American Psychiatric Association]]'s ''[[Diagnostic and Statistical Manual of Mental Disorders]]'' defined MTBI using PTA and LOC.<ref name="Petchprapai07"/> Other definitions of MTBI incorporate focal neurological deficit and altered mental status, in addition to PTA and GCS.<ref name="ComperBisschop"/>
Although the term "concussion" is still used in sports literature as interchangeable with "MHI" or "MTBI", the general clinical medical literature now uses "MTBI" instead.<ref name="BarthVarney99">
{{
cite book |author=Barth JT, Varney NR, Ruchinskas RA, Francis JP |chapter=Mild head injury: The new frontier in sports medicine |editor=Varney NR, Roberts RJ |title=The Evaluation and Treatment of Mild Traumatic Brain Injury |publisher=Lawrence Erlbaum Associates |location=Hillsdale, New Jersey |year=1999 |pages=85-86 |isbn=0-8058-2394-8 |oclc= |doi= |accessdate=2008-03-06 |url= http://books.google.com/books?id=i4Tpx6wHvJ4C&pg=PA21&vq=concussion&source=gbs_search_s&sig=t8NaFBJM5afqp0fXKb3Ou8yBjMo#PPA357,M1
}}</ref> 
Controversy exists about whether the definition of concussion should include only those injuries in which [[unconsciousness|loss of consciousness]] occurs.<ref name="Pearce"/>  Historically, concussion by definition involved a loss of consciousness, but the definition has changed over time to include a change in consciousness, such as amnesia.<ref name="RuffGrant">
{{
cite book |author=Ruff RM, Grant I |chapter=Postconcussional disorder: Background to DSM-IV and future considerations |editor=Varney NR, Roberts RJ |title=The Evaluation and Treatment of Mild Traumatic Brain Injury |publisher=Lawrence Erlbaum Associates |location=Hillsdale, New Jersey |year=1999 |pages=320 |isbn=0-8058-2394-8 |oclc= |doi= |url=http://books.google.com/books?id=i4Tpx6wHvJ4C&pg=PA21&vq=concussion&source=gbs_search_s&sig=t8NaFBJM5afqp0fXKb3Ou8yBjMo#PPA357,M1
}}</ref>  The best-known concussion grading scales count head injuries in which loss of consciousness does not occur to be mild concussions and those in which it does to be more severe.<ref name=cobb/>


==Diagnosis==
==Diagnosis==

Revision as of 14:47, 27 February 2013

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Concussion
Deceleration can exert rotational forces in the brain, especially the midbrain and diencephalon.

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Diagnosis

Diagnosis of MTBI is based on physical and neurological exams, duration of unconsciousness (usually less than 30 minutes) and post-traumatic amnesia (PTA; usually less than 24 hours), and the Glasgow Coma Scale (MTBI sufferers have scores of 13 to 15).[1] Neuropsychological tests exist to measure cognitive function.[2] The tests may be administered hours, days, or weeks after the injury, or at different times to determine whether there is a trend in the patient's condition.[3] Athletes may be tested before a sports season begins to provide a baseline comparison in the event of an injury.[4]

Unequal pupil size is a sign of a brain injury more serious than concussion.

Health care providers examine head trauma survivors to ensure that the injury is not a more severe medical emergency such as an intracranial hemorrhage. Indications that screening for more serious injury is needed include worsening of symptoms such as headache, persistent vomiting,[5] increasing disorientation or a deteriorating level of consciousness,[6] seizures, and unequal pupil size.[7] Patients with such symptoms, or who are at higher risk for a more serious brain injury, are given MRIs or CT scans to detect brain lesions and are observed by medical staff.

Health care providers make the decision about whether to give a CT scan using the Glasgow Coma Scale.[8] In addition, they may be more likely to perform a CT scan on people who would be difficult to observe after discharge or those who are intoxicated, at risk for bleeding, older than 60,[8] or younger than 16. Most concussions cannot be detected with MRI or CT scans.[9] However, changes have been reported to show up on MRI and SPECT imaging in concussed people with normal CT scans, and post-concussion syndrome may be associated with abnormalities visible on SPECT and PET scans.[10] Mild head injury may or may not produce abnormal EEG readings.[11]

Concussion may be under-diagnosed. The lack of the highly noticeable signs and symptoms that are frequently present in other forms of head injury could lead clinicians to miss the injury, and athletes may cover up their injuries in order to be allowed to remain in the competition.[12] A retrospective survey in 2005 found that more than 88% of concussions go unrecognized.[13]

Diagnosis of concussion can be complicated because it shares symptoms with other conditions. For example, post-concussion symptoms such as cognitive problems may be misattributed to brain injury when they are in fact due to post-traumatic stress disorder (PTSD).[14]

Dementia pugilistica

Chronic encephalopathy is an example of the cumulative damage that can occur as the result of multiple concussions or less severe blows to the head. The condition called dementia pugilistica, or "punch drunk" syndrome, which is associated with boxers, can result in cognitive and physical deficits such as parkinsonism, speech and memory problems, slowed mental processing, tremor, and inappropriate behavior.[15] It shares features with Alzheimer's disease.[16]

Second-impact syndrome

Second-impact syndrome, in which the brain swells dangerously after a minor blow, may occur in very rare cases. The condition may develop in people who receive a second blow days or weeks after an initial concussion, before its symptoms have gone away.[17] No one is certain of the cause of this often fatal complication, but it is commonly thought that the swelling occurs because the brain's arterioles lose the ability to regulate their diameter, causing a loss of control over cerebral blood flow.[3] As the brain swells, intracranial pressure rapidly rises.[5] The brain can herniate, and the brain stem can fail within five minutes.[17] Except in boxing, all cases have occurred in athletes under age 20.[18] Due to the very small number of documented cases, the diagnosis is controversial, and doubt exists about its validity.[19]

Related Chapters


References

  1. 3.0 3.1 Moser RS, Iverson GL, Echemendia RJ, Lovell MR, Schatz P, Webbe FM; et al. (2007). "Neuropsychological evaluation in the diagnosis and management of sports-related concussion". Archives of Clinical Neuropsychology. 22 (8): 909–916. PMID 17988831.
  2. Maroon JC, Lovell MR, Norwig J, Podell K, Powell JW, Hartl R (2000). "Cerebral concussion in athletes: Evaluation and neuropsychological testing". Neurosurgery. 47 (3): 659–669, discussion 669–672. PMID 10981754.
  3. 5.0 5.1 Cook RS, Schweer L, Shebesta KF, Hartjes K, Falcone RA (2006). "Mild traumatic brain injury in children: Just another bump on the head?". Journal of Trauma Nursing. 13 (2): 58–65. PMID 16884134.
  4. Kay A, Teasdale G (2001). "Head injury in the United Kingdom". World Journal of Surgery. 25 (9): 1210–1220. doi:10.1007/s00268-001-0084-6. PMID 11571960.
  5. "Facts About Concussion and Brain Injury". Centers for Disease Control and Prevention. 2006. Retrieved 2008-01-13.
  6. 8.0 8.1 Ropper AH, Gorson KC (2007). "Clinical practice. Concussion". New England Journal of Medicine. 356 (2): 166–172. doi:10.1056/NEJMcp064645. PMID 17215534.
  7. Poirier MP (2003). "Concussions: Assessment, management, and recommendations for return to activity (abstract)". Clinical Pediatric Emergency Medicine. 4 (3): 179–185. doi:10.1016/S1522-8401(03)00061-2. External link in |title= (help)
  8. Binder LM (1986). "Persisting symptoms after mild head injury: A review of the postconcussive syndrome". Journal of Clinical and Experimental Neuropsychology. 8 (4): 323–346. doi:10.1080/01688638608401325. PMID 3091631.
  9. Delaney JS, Abuzeyad F, Correa JA, Foxford R (2005). "Recognition and characteristics of concussions in the emergency department population". Journal of Emergency Medicine. 29 (2): 189–197. doi:10.1016/j.jemermed.2005.01.020. PMID 16029831.
  10. Mendez MF (1995). "The neuropsychiatric aspects of boxing". International Journal of Psychiatry in Medicine. 25 (3): 249–262. PMID 8567192.
  11. Jordan BD (2000). "Chronic traumatic brain injury associated with boxing". Seminars in Neurology. 20 (2): 179–85. doi:10.1055/s-2000-9826. PMID 10946737.
  12. 17.0 17.1
  13. McCrory P (2001). "Does second impact syndrome exist?". Clinical Journal of Sport Medicine. 11 (3): 144–149. PMID 11495318.

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