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{{Infobox_Disease |
 
  Name          = {{PAGENAME}} |
  Image          = Trauma subdural.jpg |
  Caption        = CT scan of a patient with a subdural hematoma |
}}
{{Traumatic brain injury}}
{{Traumatic brain injury}}
{{CMG}}
'''For patient information, click [[Traumatic brain injury (patient information)|here]]'''
==Overview==
'''Traumatic brain injury''' (TBI), traumatic injuries to the [[brain]], also called  intracranial injury, or simply head injury, occurs when [[physical trauma]] causes [[brain damage]]. TBI can result from a closed head injury or a [[penetrating head injury]] and is one of two subsets of [[acquired brain injury]] (ABI).  The other subset is non-traumatic brain injury, or injuries that do not involve external mechanical [[force]] (e.g. [[stroke]], [[meningitis]], [[Hypoxia (medical)|anoxia]]).  Parts of the brain that can be damaged include the [[cerebral hemisphere]]s, [[cerebellum]], and [[brain stem]]. 
 
TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. TBI can cause a host of physical, cognitive, emotional, and social effects. Outcome can be anything from complete recovery to permanent [[disability]] or death. 
 
==Signs and symptoms==
Some symptoms are evident immediately, while others do not surface until several days or weeks after the injury.
 
With '''mild TBI''', the patient may remain conscious or may lose consciousness for a few seconds or minutes. The person may also feel dazed or not like him- or herself for several days or weeks after the initial injury. Other symptoms include:
*[[headache]]
*[[mental confusion]]
*[[lightheadedness]]
*[[dizziness]]
*[[diplopia|double vision]], blurred vision, or tired eyes
*ringing in the ears
*bad taste in the mouth
*[[fatigue]] or [[lethargy]]
*a change in [[sleep]] patterns
*behavioral or [[mood]] changes
*trouble with [[memory]], [[concentration]], or calculation
*symptoms may remain the same or get better; worsening symptoms indicate a more severe injury
 
With '''moderate or severe TBI''', the patient may show these same symptoms, but may also have:
*loss of [[consciousness]]
*personality change
*a severe, persistent, or worsening [[headache]]
*repeated [[vomiting]] or [[nausea]]
*[[seizure]]s
*inability to awaken
*[[dilation]] (widening) of one or both pupils
*slurred [[Speech communication|speech]]
*weakness or [[numbness]] in the extremities
*loss of coordination
*increased confusion, [[restlessness]], or agitation
*vomiting and neurological deficit (e.g. weakness in a limb) together are important indicators of prognosis and their presence may warrant early [[computed axial tomography|CT scanning]] and [[neurosurgery|neurosurgical]] intervention.
 
Small children with moderate to severe TBI may show some of these signs as well as signs specific to young children, including:
*persistent crying
*inability to be consoled
*refusal to nurse or eat
 
Head injured people with signs of moderate or severe TBI should receive immediate emergency [[medical]] attention.
 
==Causes and risk factors==
[[Image:TBI causes chart.svg|thumb|left|210px|Pie chart of the causes of TBI hospital visits and deaths in the U.S.  The most common cause is falls, the second is vehicle accidents, and the third is striking or being struck by something.<ref>Centers for Disease Control and Prevention (2006). [http://www.cdc.gov/ncipc/pub-res/TBI_in_US_04/CausesTBIUpdate.pdf January 2006 Update: Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations, and Deaths]. Retrieved on [[2008-01-15]].</ref>]]
Transportation accidents involving automobiles, motorcycles, bicycles, and pedestrians cause half of all TBIs and the largest portion of TBI in people under age 75.<ref name="TBI:HTR">[http://www.ninds.nih.gov/disorders/tbi/detail_tbi.htm Traumatic Brain Injury: Hope Through Research.] NINDS. Publication date February 2002.  NIH Publication No. 02-2478. Prepared by: Office of Communications and Public Liaison, National Institute of Neurological Disorders and Stroke, National Institutes of Health
</ref>
For those aged 75 and older, falls cause the majority of TBIs.<ref name="TBI:HTR"/>
 
Approximately 20% of TBIs are due to violence, such as firearm assaults and child abuse, and about 3% are due to sports injuries.<ref name="TBI:HTR"/> Half of TBI incidents involve [[alcohol]] use.<ref name="TBI:HTR"/>
 
Traumatic brain injury is a frequent cause of major long-term disability in individuals surviving head injuries sustained in war zones.  This is becoming an issue of growing concern in modern warfare, in which rapid deployment of acute interventions are effective in saving the lives of combatants with significant head injuries.  Traumatic brain injury has been identified as the "signature injury" among wounded soldiers of the current military engagement in Iraq.<ref> [http://discovermagazine.com/2007/mar/dead-men-walking/ Iraq war's signature wound: Brain injury].  ''Discover Magazine''.</ref><ref name="Hoge08">
{{
cite journal |author=Hoge CW, McGurk D, Thomas DL, Cox AL, Engel CC, Castro CA  |title=Mild Traumatic Brain Injury in U.S. Soldiers Returning from Iraq
|journal=The New England Journal of Medicine 
|volume= 358|issue=5 |pages=453-463 |year=2008 |pmid= |doi= |url=http://content.nejm.org/cgi/content/full/358/5/453
}}
<!-- Free full text as of 2/1/08, link may die though.  Too new to be indexed on pubmed yet.-->
</ref>
 
Outcome for patients with head injury depends heavily on the cause.  For example, in the US, patients with TBIs from falls have an 89% survival rate, while only 9% of patients with firearm-related TBIs survive.<ref name="tolias">
{{
cite web | url=http://www.emedicine.com/med/topic3216.htm | title=Initial Evaluation and Management of CNS Injury | author=Tolias C and Sgouros S | date=February 4, 2005 | publisher=eMedicine.com | accessdate=2007-12-16
}}
</ref>
 
==Classification and subtypes==
===Focal vs. diffuse===
[[Image:Epidural hematoma.png|thumb|150px|left|CT scan of a patient with an epidural hematoma.]]
The damage from TBI can be focal, confined to one area of the brain, or diffuse, involving more than one area. Diffuse trauma to the brain is frequently associated with [[concussion]] (a shaking of the brain in response to sudden motion of the head), [[diffuse axonal injury]], or [[coma]].  Localized injuries may be associated with neurobehavioral manifestations, [[hemiparesis]] or other  focal neurologic deficits.  Types of focal brain injury include bruising of brain tissue called a [[brain contusion|contusion]] and [[intracranial hemorrhage]] or [[hematoma]], heavy bleeding in the skull.  Hemorrhage, due to rupture of a [[blood vessel]] in the head, can be [[extra-axial hemorrhage|extra-axial]], meaning it occurs within the [[skull]] but outside of the brain, or [[intra-axial hemorrhage|intra-axial]], occurring within the brain.  Extra-axial hemorrhages can be further divided into [[subdural hematoma]], [[epidural hematoma]], and [[subarachnoid hemorrhage]].  An epidural hematoma involves bleeding into the area between the skull and the [[dura]]. With a subdural hematoma, bleeding is confined to the area between the dura and the [[arachnoid membrane]]. A subarachnoid hemorrhage involves bleeding into the space between the surface of the brain and the arachnoid membrane that lies just above the surface of the brain, usually resulting from a tear in a blood vessel on the surface of the brain. Bleeding within the brain itself is called an intracerebral hematoma. Intra-axial bleeds are further divided into intraparenchymal hemorrhage which occurs within the brain tissue itself and intraventricular hemorrhage which occurs into the [[ventricular system]].
 
===Open vs. closed===
[[Image:Subarachnoid haemorrhage.jpg|thumb|150px|left|CT scan of a patient with a subarachnoid hemorrhage.]]
TBI can result from a closed or [[penetrating head injury]]. A closed injury occurs when the skull is not breached, while a penetrating injury occurs when an object pierces the skull and enters brain tissue.
 
As the first line of defense, the [[skull]] is particularly vulnerable to injury. [[Skull fracture]]s occur when a bone in the skull cracks or breaks. A depressed skull fracture occurs when pieces of the broken skull press into the tissue of the brain. A penetrating skull fracture occurs when something pierces the skull, such as a bullet, leaving a distinct and localized traumatic injury to brain tissue.  Skull fractures can cause [[cerebral contusion]].
 
===Severity===
{|  align="right" border="1" style="text-align: center;"
|+ ''' Levels of TBI severity'''<ref name="RaoLyketsos"/>
! &nbsp; !! GCS !! PTA !! LOC
|-
! Mild
|align="center" | 13 to 15 || <1<br> hour || <30<br> minutes
|-
! Moderate
| 9 to 12 || 30 minutes<br> to 24 hours || 1 to 24<br> hours
|-
! Severe
| <8 || >1 day || >24 <br>hours
|}
 
Head injuries can be subdivided into mild, moderate, and severe TBI to help predict outcome.  One common classification system determines severity based on the [[Glasgow Coma Scale]] (GCS) and duration of [[post-traumatic amnesia]] (PTA) and [[loss of consciousness]] (LOC) according to the table at right.<ref name="RaoLyketsos"/> Other classification systems use GCS alone or PTA or LOC alone or together.<ref name="RaoLyketsos"/>  Prognosis worsens with the severity of injury, but mild TBI is more poorly defined and prognosis is not as clear with it.<ref name="RaoLyketsos"/> 
 
Mild TBI is also commonly called [[concussion]]. Though prognosis for concussion is usually very good, a portion of people may suffer lasting problems associated with the injury, such as [[post-concussion syndrome]].  A patient who receives a second concussion before symptoms from another one have healed is at risk for developing a very rare but deadly condition called [[second-impact syndrome]], in which the brain swells catastrophically after even a mild blow.
 
==Pathophysiology==
 
Unlike most forms of traumatic death, a large percentage of the people killed by brain trauma do not die right away but rather days to weeks after the event.<ref>Sauaia A, Moore FA, Moore EE, Moser KS, Brennan R, Read RA, and Pons PT.  1995.  Epidemiology of trauma deaths: a reassessment. ''Journal of Trauma'', Volume 38, Issue 2, Pages 185-193. PMID 7869433</ref>  Rather than improving after being hospitalized, some 40% of TBI patients deteriorate.<ref>Narayan RK, Michel ME, Ansell B, Baethmann A, Biegon A, Bracken MB, Bullock MR, Choi SC, Clifton GL, Contant CF, Coplin WM, Dietrich WD, Ghajar J, Grady SM, Grossman RG, Hall ED, Heetderks W, Hovda DA, Jallo J, Katz RL, Knoller N, Kochanek PM, Maas AI, Majde J, Marion DW, Marmarou A, Marshall LF, McIntosh TK, Miller E, Mohberg N, Muizelaar JP, Pitts LH, Quinn P, Riesenfeld G, Robertson CS, Strauss KI, Teasdale G, Temkin N, Tuma R, Wade C, Walker MD, Weinrich M, Whyte J, Wilberger J, Young AB, Yurkewicz L.  2002.  Clinical trials in head injury.  ''Journal of Neurotrauma'', Volume 19, Issue 5, Pages 503-557. PMID 12042091</ref>  Primary injury (the damage that occurs at the moment of trauma when tissues and blood vessels are stretched, compressed, and torn) is not adequate to explain this degeneration.  Rather, the deterioration is caused by secondary injury, a complex set of [[biochemical cascade]]s that occur in the minutes to days following the trauma<ref>Xiong Y, Lee CP, and Peterson PL.  2001.  Mitochondrial dysfunction following traumatic brain injury.  In ''Head Trauma: Basic, Preclinical, and Clinical Directions''.  Miller LP and Hayes RL, eds.  Co-edited by Newcomb JK.  2001, John Wiley and Sons, Inc. New York. Pages 257-280.</ref> and contribute a large amount to morbidity and mortality from TBI.<ref>Sullivan PG, Rabchevsky AG, Hicks RR, Gibson TR, Fletcher-Turner A, and Scheff SW.  2000.  Dose-response curve and optimal dosing regimen of cyclosporin A after traumatic brain injury in rats.  ''Neuroscience'', Volume 101, Issue 2, Pages 289-295. PMID 11074152</ref>
 
Secondary injury events are poorly understood but are thought to include [[cerebral edema|brain swelling]], alterations in [[cerebral blood flow]], a decrease in the tissues' [[pH]], [[free radical]] overload, and [[excitotoxicity]].  These secondary processes damage neurons that were not directly harmed by the primary injury.
 
==Effects==
 
The results of traumatic brain injury vary widely in type and duration.  A head injured patient may experience physical effects of the trauma such as [[headache]]s, movement disorders (e.g. [[Parkinsonism]]), [[seizures]], difficulty walking, [[sexual dysfunction]], lethargy, or [[coma]].  Cognitive symptoms include changes in judgment or ability to reason or plan, memory problems, and loss of mathematical ability.  Emotional problems include mood swings, poor impulse control, agitation, low frustration threshold, self-centeredness, [[clinical depression]], and [[Psychosis|psychotic]] symptoms such as [[hallucination]]s and [[delusion]]s.
 
===Effects on consciousness===
Generally, there are six abnormal states of consciousness that can result from a TBI: [[stupor]], [[coma]], [[persistent vegetative state]], [[minimally conscious state]], [[locked-in syndrome]], and [[brain death]].
 
[[Stupor]] is a state in which the patient is unresponsive but can be aroused briefly by a strong stimulus, such as sharp pain. [[Coma]] is a state in which the patient is totally unconscious, unresponsive, unaware, and unarousable.
 
Patients in a [[persistent vegetative state]] are unconscious and unaware of their surroundings, but they continue to have a sleep-wake cycle and can have periods of alertness. A vegetative state can result from diffuse injury to the cerebral hemispheres of the brain without damage to the lower brain and brainstem.
 
Patients in a [[minimally conscious state]] have a reduced level of arousal and may appear, on the surface, to be in a [[persistent vegetative state]] but are capable of demonstrating the ability to actively process information.  In the minimally conscious state a patient exhibits deliberate, or cognitively mediated, behavior often enough, or consistently enough, for clinicians to be able to distinguish it from the entirely unconscious, reflexive responses that are seen in the [[persistent vegetative state]].  Differentiating a patient in a [[persistent vegetative state]] from one in a minimally conscious state can be challenging but remains a critically important clinical task.
 
[[Locked-in syndrome]] is a condition in which a patient is aware and awake, but cannot move or communicate due to complete paralysis of the body.  Voluntary control of eye movements or blinking may be spared permitting the detection of conscious awareness and enabling the establishment of functional communication.
 
[[Brain death]] is the lack of measurable brain function due to diffuse damage to the cerebral hemispheres and the brainstem, with loss of any integrated activity among distinct areas of the brain. Brain death is irreversible. Removal of assistive devices will result in immediate cardiac arrest and cessation of breathing.
 
Recent studies have brought into question the nature of coma and consciousness in TBI.  For example, a 23 year old woman in a [[vegetative state]] after a severe brain injury due to a car accident was able to communicate with a team of British researchers at Cambridge University in England via functional [[magnetic resonance imaging]].<ref name="BBC news ">{{cite web | url=http://news.bbc.co.uk/2/hi/health/5320234.stm | title= Vegetative patient 'communicates': A patient in a vegetative state can communicate just through using her thoughts, according to research. | author= | date= September 7, 2006| publisher=BBC News | accessdate=2007-09-26 }}</ref>  While cautious about accepting the study's results, Nicholas Schiff, a neurologist at the [[Weill Cornell Medical College]] in New York, agrees that the research was groundbreaking. "It's the first time we've ever seen something like this. It really is kind of shocking," he said.<ref name="Stein ">{{cite web | url=http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/09/08/MNGI9L1IM81.DTL | title=Vegetative patient's brain active in test: Unprecedented experiment shows response to instructions to imagine playing tennis | author=Stein R | date=September 8, 2006 | publisher= ''San Francisco Chronicle''| accessdate=2007-09-26 }}</ref>
 
===Complications===
Health complications may occur in the period immediately following a TBI. These complications are not types of TBI, but are distinct medical problems that arise as a result of the injury. Although complications are rare, the risk increases with the severity of the trauma.<ref name="TBI:HTR"/> Complications of TBI include immediate [[seizure]]s, [[hydrocephalus]] or post-traumatic ventricular enlargement, [[cerebrospinal fluid]] leaks, [[infection]]s, vascular injuries, [[cranial nerve]] injuries, and [[Pain and nociception|pain]].<ref name="TBI:HTR"/> Serious complications for patients who are unconscious, in a coma, or in a vegetative state include [[pressure sores]] of the skin, [[pneumonia]] or other infections, and progressive [[multiple organ failure]].<ref name="TBI:HTR"/>
 
Hydrocephalus or post-traumatic [[brain ventricle|ventricular]] enlargement occurs when [[cerebrospinal fluid]] (CSF) accumulates in the brain resulting in dilation of the cerebral ventricles (cavities in the brain filled with CSF) and an increase in ICP. This condition can develop during the acute stage of TBI or may not appear until later. Generally it occurs within the first year of the injury and is characterized by worsening neurological outcome, impaired consciousness, behavioral changes, ataxia (lack of coordination or balance), incontinence, or signs of elevated ICP.<ref name="TBI:HTR"/> The condition may develop as a result of meningitis, subarachnoid hemorrhage, intracranial hematoma, or other injuries.<ref name="TBI:HTR"/> Treatment includes shunting and draining of CSF as well as any other appropriate treatment for the root cause of the condition.
 
[[Skull fracture]]s can tear the meninges, the membranes that cover the brain, leading to CSF leaks. A tear between the dura and the arachnoid membranes, called a [[CSF]] [[fistula]], can cause CSF to leak out of the subarachnoid space into the subdural space; this is called a [[subdural hygroma]].<ref name="TBI:HTR"/> CSF can also leak from the nose and the ear. These tears that let CSF out of the brain cavity can also allow bacteria into the cavity, potentially causing [[infection]]s such as [[meningitis]].<ref name="TBI:HTR"/> [[Pneumocephalus]] occurs when air enters the [[intracranial cavity]] and becomes trapped in the subarachnoid space.<ref name="TBI:HTR"/> Infections within the intracranial cavity are a dangerous complication of TBI. They may occur outside of the [[dura mater]], below the dura, below the [[arachnoid mater|arachnoid]] ([[meningitis]]), or within the brain itself ([[abscess]]).<ref name="TBI:HTR"/> Most of these injuries develop within a few weeks of the initial trauma and result from [[skull fracture]]s or penetrating injuries.<ref name="TBI:HTR"/> Standard treatment involves [[antibiotics]] and sometimes surgery to remove the infected tissue.<ref name="TBI:HTR"/> Meningitis may be especially dangerous, with the potential to spread to the rest of the brain and [[nervous system]].
 
Any damage to the head or brain usually results in some damage to the [[vascular system]], which provides [[blood]] to the cells of the brain. The body can repair damage to small blood vessels, but damage to larger vessels can result in serious complications. Damage to one of the major arteries leading to the brain can cause a stroke, either through bleeding from the artery ([[hemorrhagic stroke]]) or through the formation of a clot at the site of injury, called a [[thrombus]] or thrombosis, blocking blood flow to the brain ([[ischemic stroke]]). Blood clots also can develop in other parts of the head. Symptoms such as headache, vomiting, [[seizure]]s, [[hemiplegia|paralysis on one side of the body]], and semiconsciousness developing within several days of a head injury may be caused by a blood clot that forms in the tissue of one of the sinuses, or cavities, adjacent to the brain.<ref name="TBI:HTR"/> Other types of vascular injuries include [[vasospasm]] and the formation of [[aneurysm]]s.
 
[[Skull fracture]]s, especially at the base of the skull, can cause cranial nerve injuries that result in compressive cranial neuropathies]]. All but three of the twelve cranial nerves project out from the brainstem to the head and face. Damage to the [[seventh cranial nerve]], the most commonly injured cranial nerve in TBI, can result in paralysis of facial muscles.<ref name="TBI:HTR"/>
 
Pain, especially headache, is a common complication following a TBI. 
 
Fluid and hormonal imbalances can complicate the treatment of [[hypermetabolism]] and high [[intracranial pressure]] (ICP). Hormonal problems can result from dysfunction of the [[pituitary]], the [[thyroid]], and other glands throughout the body. Two common hormonal complications of TBI are syndrome of inappropriate secretion of antidiuretic hormone ([[SIADH]]) and [[hypothyroidism]].<ref name="TBI:HTR"/>
 
Trauma victims often develop [[hypermetabolism]] or an increased metabolic rate, which leads to an increase in the amount of heat the body produces. The body redirects into heat the energy needed to keep organ systems functioning, causing [[muscle wasting]] and the starvation of other tissues.  The nutritional management of patients with TBI, including the provision of adequate [[calorie (food)|calorie]]s and [[protein]] through an available [[route of administration]] to balance consumption, is thus critically important in order to avoid complications related to hypermetabolism and resulting [[malnutrition]].  Provision of food through a [[feeding tube]] may be temporarily necessary to meet the nutritional needs of the patient with a severe TBI, until they are awake and able to eat and swallow safely without risking [[pulmonary aspiration]] and the development of [[aspiration pneumonia]].  Sometimes the use of [[parenteral]] feeding is necessary if the patient has associated injuries or complications that prevent direct access to the digestive system.
 
===Disabilities resulting from TBI===
Disabilities resulting from a TBI depend upon the severity of the injury, the location of the injury, and the age and general health of the patient. Some common disabilities include problems with cognition (attention, calculation, memory, judgment, insight, and reasoning), sensory processing (sight, hearing, touch, taste, and smell), communication (language expression and understanding), social function ([[empathy]], capacity for compassion, interpersonal social awareness and facility) and mental health ([[major depression|depression]], [[anxiety]], personality changes, aggression, acting out, and social inappropriateness).<ref name="TBI:HTR"/>


====Postconcussion syndrome====
{{CMG}} {{AE}}, {{JE}} {{Deekshitha}}
{{main|postconcussion syndrome}}
Within days to weeks of the head injury, approximately 40% of TBI patients develop a host of troubling symptoms collectively called [[postconcussion syndrome]] (PCS).<ref name="TBI:HTR"/> A patient need not have suffered a loss of consciousness to develop the syndrome.<ref name="TBI:HTR"/> Symptoms include [[headache]], [[dizziness]], memory problems, trouble concentrating, sleeping problems, restlessness, irritability, apathy, [[clinical depression]], and anxiety.<ref name="TBI:HTR"/> These symptoms may last for a few weeks after the head injury. The syndrome is more prevalent in patients who had psychiatric symptoms, such as depression or anxiety, before the injury.<ref name="TBI:HTR"/> Treatment involves treating symptoms, for example giving medicines for pain and psychiatric conditions, and [[psychotherapy]] and [[occupational therapy]].


====Cognitive problems====
{{SK}} TBI; intracranial injury
Most patients with severe TBI who recover consciousness suffer from [[cognitive disabilities]], including the loss of many higher level mental skills. The most common cognitive impairment among severely head-injured patients is [[memory loss]], characterized by some loss of specific memories and the partial inability to form or store new ones. Some of these patients may experience [[post-traumatic amnesia]] (PTA), either [[anterograde amnesia|anterograde]] or [[retrograde amnesia|retrograde]]. Anterograde PTA is impaired memory of events that happened after the TBI, while retrograde PTA is impaired memory of events that happened before the TBI.
==[[Traumatic brain injury overview|Overview]]==


Many patients with mild to moderate head injuries who experience cognitive deficits become easily confused or distracted and have problems with concentration and [[attention]]. They also have problems with higher level, so-called executive functions, such as planning, organizing, abstract reasoning, problem solving, and making judgments, which may make it difficult to resume pre-injury activities. Recovery from cognitive deficits is greatest within the first six months after the injury and more gradual after that.<ref name="TBI:HTR"/>
==[[Traumatic brain injury historical perspective|Historical Perspective]]==


Patients with moderate to severe TBI have more problems with cognitive deficits than patients with mild TBI, but a history of several mild TBIs may have an additive effect.<ref name="TBI:HTR"/>
==[[Traumatic brain injury classification|Classification]]==


Language and communication problems are common disabilities in TBI patients. Some may experience [[aphasia]], defined as difficulty with understanding and producing spoken and written language; others may have difficulty with the more subtle aspects of communication, such as body language and emotional, non-verbal signals.  TBI patients may have problems with spoken language if the part of the brain that controls speech muscles is damaged. In this disorder, called [[dysarthria]], the patient can think of the appropriate language, but cannot easily speak the words because they are unable to use the muscles needed to form the words and produce the sounds. Speech is often slow, slurred, and garbled. Some may have problems with intonation or inflection, called prosodic dysfunction.
==[[Traumatic brain injury pathophysiology|Pathophysiology]]==


Alzheimer's disease (AD) is a progressive, neurodegenerative disease characterized by [[dementia]], memory loss, and deteriorating cognitive abilities. Research suggests an association between head injury in early adulthood and the development of AD later in life; the more severe the head injury, the greater the risk of developing AD.<ref name="TBI:HTR"/> Some evidence indicates that a head injury may interact with other factors to trigger the disease and may hasten the onset of the disease in individuals already at risk. For example, people who have a particular form of the protein [[apolipoprotein E]] (apoE4) and suffer a head injury fall into this increased risk category.<ref name="TBI:HTR"/> (ApoE4 is a naturally occurring protein that helps transport cholesterol through the bloodstream.)
==[[Traumatic brain injury causes|Causes]]==


[[Dementia pugilistica]], also called chronic traumatic [[encephalopathy]], primarily affects career boxers. The most common symptoms of the condition are [[dementia]] and [[parkinsonism]] caused by repetitive blows to the head over a long period of time. Symptoms begin anywhere between 6 and 40 years after the start of a boxing career, with an average onset of about 16 years.<ref name="TBI:HTR"/>
==[[Traumatic brain injury differential diagnosis|Differentiating Traumatic Brain Injury from other Diseases]]==


Post-traumatic dementia is another potential long-term effect of TBI.  The symptoms of post-traumatic dementia are very similar to those of dementia pugilistica, except that post-traumatic dementia is also characterized by long-term memory problems and is caused by a single, severe TBI that results in a [[coma]].<ref name="TBI:HTR"/>
==[[Traumatic brain injury epidemiology and demographics|Epidemiology and Demographics]]==


====Sensory deficits====
==[[Traumatic brain injury risk factors|Risk Factors]]==
Many TBI patients have sensory problems, especially problems with [[Visual perception|vision]]. Patients may not be able to register what they are seeing or may be slow to recognize objects. Also, TBI patients often have difficulty with hand-eye coordination. Because of this, TBI patients may seem clumsy or unsteady. Other sensory deficits may include problems with [[hearing (sense)|hearing]], [[Olfaction|smell]], [[taste]], or [[somatosensory system|touch]]. Some TBI patients develop [[tinnitus]], a ringing or roaring in the ears. A person with damage to the part of the brain that processes taste or smell may develop a persistent bitter taste in the mouth or perceive a persistent noxious smell. Damage to the part of the brain that controls the sense of touch may cause a TBI patient to develop persistent skin tingling, itching, or pain. These conditions are rare and hard to treat.


====Emotional and behavioral problems====
==[[Traumatic brain injury screening|Screening]]==
Most TBI patients have emotional or behavioral problems that fit under the broad category of psychiatric health. Family members of TBI patients often find that personality changes and behavioral problems are the most difficult disabilities to handle. Psychiatric problems that may persist for one half year to two years after the injury may include irritability, [[suicidal ideation]], [[insomnia]], and [[anhedonia|loss of the ability to experience pleasure]] from previously enjoyable experiences.<ref name="RaoLyketsos"/>
Other problems include apathy, anxiety, anger, [[paranoia]], confusion, frustration, agitation, and [[mood swing]]s. About one quarter of people with TBI suffer from [[clinical depression]], and about 9% suffer [[mania]].<ref name="RaoLyketsos"/> Problem behaviors may include [[aggression]] and violence, impulsivity, disinhibition, acting out, noncompliance, social inappropriateness, emotional outbursts, childish behavior, impaired self-control, impaired self-awareness, inability to take responsibility or accept criticism, egocentrism, inappropriate sexual activity, and [[alcohol abuse|alcohol]] or [[drug abuse]] or [[addiction]].  Some patients' personality problems may be so severe that they are diagnosed with organic personality disorder, a psychiatric condition characterized by many of these problems. Sometimes TBI patients suffer from developmental stagnation, meaning that they fail to mature emotionally, socially, or psychologically after the trauma. This is a serious problem for children and young adults who suffer from a TBI, because attitudes and behaviors that are appropriate for a child or teenager become inappropriate in adulthood. TBI patients who show psychiatric or behavioral problems may be helped with medication and psychotherapy, although the effectiveness of psychotherapy may be limited by the residual neurocognitive impairment. Technological improvements and emergency  care have diminished the incidence of devastating TBI while increasing the numbers of patients with mild or moderate TBI. Such patients are more adversely affected by their emotional problems than by their residual physical disabilities.


====Physical problems====
==[[Traumatic brain injury natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
''Parkinson's disease'' and other motor problems as a result of TBI are rare but can occur. Parkinson's disease may develop years after TBI as a result of damage to the [[basal ganglia]]. Symptoms of Parkinson's disease include [[tremor]] or trembling, rigidity or stiffness, slow movement ([[bradykinesia]]), inability to move ([[akinesia]]), shuffling walk, and stooped posture. Despite many scientific advances in recent years, Parkinson's disease remains a chronic and progressive disorder, meaning that it is incurable and will progress in severity until the end of life. Other movement disorders that may develop after TBI include tremor, [[ataxia]] (uncoordinated muscle movements), and [[myoclonus]] (shock-like contractions of muscles).<ref name="TBI:HTR"/>


About 25% of patients with brain contusions or hematomas and about 50% of patients with penetrating head injuries will develop immediate seizures, seizures that occur within the first 24 hours of the injury.<ref name="TBI:HTR"/> These immediate seizures increase the risk of early seizures - defined as seizures occurring within 1 week after injury - but do not seem to be linked to the development of [[post-traumatic epilepsy]] (recurrent [[post-traumatic seizure]]s occurring more than 1 week after the initial trauma).<ref name="TBI:HTR"/> Generally, medical professionals use anticonvulsant medications to treat seizures in TBI patients only if the seizures persist.<ref name="TBI:HTR"/>
==Diagnosis==
 
[[Traumatic brain injury Diagnostic study of choice|Diagnositic study of choice]] | [[Traumatic brain injury history and symptoms|History and Symptoms]] | [[Traumatic brain injury physical examination|Physical Examination]] | [[Traumatic brain injury laboratory findings|Laboratory Findings]] | [[Traumatic brain injury Electrocardiogram|Electrocardiogram]] | [[Traumatic brain injury x ray| X Ray]] | [[Traumatic brain injury Echocardiography and Ultrasound|Echocardiography and Ultrasound]] | [[Traumatic brain injury CT|CT]] | [[Traumatic brain injury MRI|MRI]] | [[Traumatic brain injury other imaging findings|Other Imaging Findings]] | [[Traumatic brain injury other diagnostic studies|Other Diagnostic Studies]]
==Prevention==
The [[Centers for Disease Control and Prevention]] (CDC) have suggested taking the following safety precautions for reducing the risk of suffering a TBI.<ref name="cdctips">[http://www.cdc.gov/safeusa/home/tbi.htm CDC, Department of Health and Human Services].</ref>
 
* Wearing a seatbelt.
* Buckling children into a child safety seat, booster seat, or seatbelt (depending on the child's age) every time the child rides in a car.
* Wearing a helmet and making sure children wear helmets when
** riding a bike or motorcycle;
** playing a contact sport such as American football or ice hockey;
** using in-line skates or riding a skateboard;
** batting and running bases in baseball or softball;
** riding a horse;
** rock climbing;
** sledding;
** skiing or snowboarding.
* Keeping firearms and bullets stored in a locked cabinet when not in use.
* Avoiding falls by
** using a step-stool with a grab bar to reach objects on high shelves;
** installing handrails on stairways;
** installing window guards to keep young children from falling out of open windows;
** using safety gates at the top and bottom of stairs when young children are around.
* Using only playgrounds with surfaces made of shock-absorbing material (e.g. mulch, sand).


==Treatment==
==Treatment==
Medical care usually begins when [[paramedic]]s or [[emergency medical technician]]s arrive on the scene of an accident or when a TBI patient arrives at the emergency department of a hospital. Because little can be done to reverse the initial brain damage caused by trauma, medical personnel try to stabilize the patient and focus on preventing further injury. Primary concerns include insuring proper [[oxygen]] supply, maintaining adequate blood flow, and controlling [[blood pressure]]. Since many head-injured patients may also have [[spinal cord injury|spinal cord injuries]], the patient is placed on a back-board and in a neck restraint to prevent further injury to the head and spinal cord.
[[Traumatic brain injury medical therapy|Medical Therapy]] | [[Traumatic brain injury Interventions|Interventions]] | [[Traumatic brain injury surgery|Surgery]] | [[Traumatic brain injury primary prevention|Primary Prevention]] | [[Traumatic brain injury Secondary Prevention|Secondary Prevention]] | [[Traumatic brain injury cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Traumatic brain injury future or investigational therapies|Future or Investigational Therapies]]
 
Medical personnel assess the patient's condition by measuring [[vital signs]] and reflexes and by performing a neurological examination. They assess the patient's level of consciousness and neurological functioning using the [[Glasgow Coma Scale]]. 
 
Imaging tests help in determining the diagnosis and prognosis of a TBI patient. Patients with mild to moderate injuries may receive skull and neck [[X-ray]]s to check for [[bone fracture]]s.  For moderate to severe cases, the gold standard imaging test is a [[computed tomography]] (CT) scan, which creates a series of cross-sectional X-ray images of the head and brain and can show bone fractures as well as the presence of hemorrhage, hematomas, contusions, brain tissue swelling, and tumors. [[Magnetic resonance imaging]] (MRI), which can show more detail than X-rays or CT, may be used.  CT and MRI is standard in TBI treatment, but other imaging and diagnostic techniques that may be used to confirm a particular diagnosis include [[cerebral angiography]], [[electroencephalography]] (EEG), transcranial Doppler ultrasound, and [[single photon emission computed tomography]] (SPECT).
 
Approximately half of severely head-injured patients will need [[surgery]] to remove or repair hematomas or contusions.<ref name="TBI:HTR"/> Patients may also need surgery to treat injuries in other parts of the body. These patients usually go to the [[intensive care unit]] after surgery. 
 
Sometimes when the brain is injured swelling occurs and fluids accumulate within the brain space. When an injury occurs inside the skull-encased brain, there is no place for swollen tissues to expand and no adjoining tissues to absorb excess fluid.  This leads to an increase in the pressure within the skull, called [[intracranial pressure]] (ICP).  High ICP can cause delicate brain tissue to be crushed, or parts of the brain to [[brain herniation|herniate]] across structures within the skull, potentially leading to severe damage. Medical personnel measure a patient's ICP using a probe or catheter. The instrument is inserted through the skull to the [[subarachnoid space|subarachnoid]] level and is connected to a monitor that registers ICP. If a patient has high ICP, he or she may undergo a [[ventriculostomy]], a procedure that drains [[cerebrospinal fluid]] (CSF) from the [[ventricular system|ventricles]] to bring the pressure down by way of an external ventricular drain.
 
[[Barbiturate]]s can be used to decrease ICP; [[mannitol]] was thought to be useful, but it appears likely that the studies suggesting that it was of use<ref>Cruz J, Minoja G, Okuchi K. (2001) Improving clinical outcomes from acute subdural hematomas with the emergency preoperative administration of high doses of mannitol: a randomized trial. ''Neurosurgery''. Volume 49, Issue 4, Pages 864-871. PMID 11564247</ref><ref>Cruz J, Minoja G, Okuchi K. (2002) Major clinical and physiological benefits of early high doses of mannitol for intraparenchymal temporal lobe hemorrhages with abnormal pupillary widening: a randomized trial. ''Neurosurgery''. Volume 51, Issue 3, Pages 628-637; discussion 637-638. PMID 12188940</ref><ref>Cruz J, Minoja G, Okuchi K, Facco E. (2004) Successful use of the new high-dose mannitol treatment in patients with Glasgow Coma Scale scores of 3 and bilateral abnormal pupillary widening: a randomized trial. ''Journal of Neurosurgery''. Volume 100, Issue 3, Pages 376-383. PMID 15035271</ref> may have been falsified<ref>Roberts I, Smith R, Evans S. (2007) [http://www.bmj.com/cgi/content/full/334/7590/392 Doubts over head injury studies.] ''BMJ''. Volume 334, Issue 7590, Pages 392-394. PMID 17322250</ref>.
 
[[Decompressive craniectomy]] is a last-resort surgical procedure in which part of the skull is removed in an attempt to reduce severely high ICP.<ref name="Aarabi">Aarabi B, Hesdorffer DC, Ahn ES, Aresco C, Scalea TM, and Eisenberg HM. (2006) Outcome following decompressive craniectomy for malignant swelling due to severe head injury. ''Journal of Neurosurgery''. Volume 104, Issue 4, Pages 469-479. PMID 16619648. Retrieved on [2007-01-21]] </ref>
 
== Rehabilitation ==
Rehabilitation is a critical part of recovery from TBI.  During the acute stage, moderately to severely injured patients may receive treatment and care in an [[intensive care unit]] of a hospital followed by movement to a step-down unit or to a [[neurosurgery|neurosurgical]] ward.  Once medically stable, the patient may be transferred to a [[subacute]] unit of the medical center, to a long-term acute care (LTAC) facility, to a rehabilitation [[Outpatient#Outpatient vs Inpatient|inpatient]] treatment unit contained within the acute trauma center, or to an independent off-site [[rehabilitation hospital]].  Some inpatient treatment units have a specialty focus in brain injury rehabilitation. 
 
Decisions regarding when and where an individual should be treated depend on many different factors including the level to which the person can participate in the rehabilitation process.  Moderately to severely injured patients may receive treatment from programs including [[physical therapy]], [[occupational therapy]], [[Speech and language pathology|speech and language therapy]], physiatry ([[physical medicine and rehabilitation]]), [[psychology]], [[psychiatry]], and [[social work]].  The services and efforts of this team of healthcare professionals are generally applied to the practical concerns of the survivor.  This treatment program is generally provided through a coordinated and self-organized process in the context of a [[transdisciplinary]] model of team healthcare delivery.  The overall goal of rehabilitation after a TBI is to improve the patient's ability to function independently at home and in society.  Therapists help the patient adapt to disabilities or change the patient's living conditions to accommodate impairments.  Education and training for caregivers are also critical components of the rehabilitation program.
 
After discharge from the inpatient rehabilitation treatment unit, the [[Outpatient#Outpatient vs Inpatient|outpatient]] phase of care begins and goals often will shift from assisting the person to achieve independence in basic routines of daily living to treating broader psychosocial issues associated with long-term adjustment and community reintegration.  Patients will often have problems in areas including [[cognition]], social awareness, and behavior and emotional regulation, often complicated by difficulty adjusting to deficits.  Other concerns such as [[posttraumatic stress disorder]] associated with disturbing memories surrounding the injury, may emerge and complicate recovery.
 
An additional goal of the rehabilitation program is to prevent, or failing that, to diagnose and treat TBI complications that may cause additional [[morbidity]] and mortality. 
 
Some patients may need [[medication]] for psychiatric and physical problems resulting from the TBI.  TBI patients are more susceptible to side effects and may react adversely to some [[pharmacology|pharmacological]] agents or may be inordinately sensitive to them, for example, due to a more permeable [[blood-brain barrier]] that may result from injury.
 
It is important for caregivers to assist and encourage the patient by being involved in the rehabilitation program.  Family members may also benefit from [[psychotherapy]] and social support services.  Caretakers often feel a great deal of [[emotional stress]], which can reduce the quality of their care. Support for caregivers becomes particularly important during the outpatient phase of care when behavioral and cognitive problems may complicate patients' relationships, particularly in marriage. [[Respite care]] such as supported living and residential holidays, with supported days out, offers relief for caregivers and a new area of brain stimulation for the patient.
 
== Epidemiology ==
The [[incidence (epidemiology)|incidence]] of TBI varies by age, gender, region and other factors.<ref name="D'AmbrosioPerucca04"/>  For example, the yearly incidence in the U.S. is estimated to be about 1.8 to 2.5 per 1000 people, but the incidence is thought to be higher in Europe and South Africa.<ref name="D'AmbrosioPerucca04"/>
 
The age groups most at risk for TBI are children ages five to nine and adults over age 80.<ref name="RaoLyketsos"/> Children age five and younger are also at high risk for TBI.<ref name="TBI:HTR"/>  Men suffer twice as many TBIs as women do and have a four fold risk of fatal head injury.<ref name="RaoLyketsos"/> Males also account for two thirds of childhood and adolescent head trauma patients.<ref name="Necajauskaite 05">
{{
cite journal | last =Necajauskaite  | first =O | authorlink = | coauthors =Endziniene M, Jureniene K | title =The prevalence, course and clinical features of post-concussion syndrome in children | journal =Medicina (Kaunas) | volume = 41| issue = 6| pages =457-464 | publisher = | date =2005 | url =http://medicina.kmu.lt/0506/0506-01e.pdf | doi = | pmid=15998982 | accessdate =2008-02-29
}}
</ref> 
 
Each year in the United States:
* about two million people suffer a TBI<ref name="RaoLyketsos">
{{
cite journal |author=Rao V, Lyketsos C |title=Neuropsychiatric Sequelae of Traumatic Brain Injury |journal=Psychosomatics |volume=41 |issue=2 |pages=95–103 |year=2000 |pmid=10749946 |doi=
}}
</ref>
* about 500,000 people are hospitalized for TBI<ref name="D'AmbrosioPerucca04">
{{
cite journal |author=D'Ambrosio R, Perucca E |title=Epilepsy After Head Injury |journal=Current Opinion in Neurology |volume=17 |issue=6 |pages=731–735 |year=2004 |pmid=15542983 |doi=
}}
</ref>
* approximately 270,000 people experience a moderate or severe TBI,
* approximately 60,000 new cases of [[epilepsy]] occur as a result of [[head trauma]],
* approximately 50,000 people die from [[head injury]],<ref name="TBI:HTR"/>
* and approximately 80,000 of these survivors live with [[chronic]] disabilities as a result of the injury.<ref name="RaoLyketsos"/>
 
== Famous persons with TBI ==
* Muhammad Ali
* James Brady
* Phineas Gage
* Chris Irwin
* Ahad Israfil
* Eric Lindros
* Kurt Vonnegut
* Bob Woodruff
* Chris Nowinski


==References==
==Case Studies==
{{Reflist|2}}
[[Traumatic brain injury case study one|Case #1]]


== See also ==
==Related Chapters==


* [[Head injury]]
*[[Head injury]]
:* [[Brain damage]]
*[[Brain damage]]
:* [[Coma]]
*[[Coma]]
:* [[Unconsciousness]]
*[[Unconsciousness]]
:* [[Vegetative state]]
*[[Vegetative state]]
:* [[Penetrating head injury]]
*[[Penetrating head injury]]
:* [[Concussion]]
*[[Concussion]]
:* [[Diffuse axonal injury]]
*[[Diffuse axonal injury]]
:* [[Brain contusion]]
*[[Brain contusion]]
:* [[Intracranial hemorrhage]]
*[[Intracranial hemorrhage]]
::* [[Intra-axial hemorrhage]]
::* [[Extra-axial hemorrhage]]
:::* [[Subdural hematoma]]
:::* [[Epidural hematoma]]
:::* [[Subarachnoid hemorrhage]]
* [[Spinal cord injury]]
* [[NINDS brain trauma research]]
* [[Brain Trauma Foundation]]


==External links==
:*[[Intra-axial hemorrhage]]
* [http://www.charlesmaddockfoundation.org/ Charles Maddock Foundation ]
:*[[Extra-axial hemorrhage]]
* [http://www.tbirecovery.org/ The Brain Injury Recovery Network ]
::*[[Subdural hematoma]]
* [http://www.internationalbrain.org/ International Brain Injury Association (IBIA)]
::*[[Epidural hematoma]]
* [http://www.biausa.org/ Brain Injury Association of America]
::*[[Subarachnoid hemorrhage]]
* [http://www.braintrauma.org/ Brain Trauma Foundation]
* [http://www.braininjury.org.au/ Fact sheets on brain injury, its effects, and strategies for survivors and their families]
* [http://www.carepages.com/brain-injury/index.jsp Brain Injury Support Group]
* [http://www.neuroskills.com TBI Resource Guide] Traumatic Brain Injury Resource Guide
* [http://www.birf.info The Brain Injury Resource Foundation] The Brain Injury Resource Foundation
* [http://www.headway.org.uk/default.asp Headway - the brain injury association] UK based charity providing information and support.
* [http://www.neure.com Neurotrauma Registry] - an online Directory of brain injury resources in the United States.
* [http://www.army.mil/-news/2007/08/01/4249-ptsd-mild-tbi-chain-teaching-begins-at-pentagon/ PTSD, Mild TBI Chain Teaching Begins at Pentagon]  


''The original version of this article contained text from the [http://www.ninds.nih.gov/disorders/tbi/detail_tbi.htm NINDS public domain pages on TBI]''
*[[Spinal cord injury]]
*[[NINDS brain trauma research]]
*[[Brain Trauma Foundation]]


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Latest revision as of 00:47, 4 September 2021


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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: , Joanna Ekabua, M.D. [2] Deekshitha Manney, M.D.[[3]]

Synonyms and keywords: TBI; intracranial injury

Overview

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Screening

Natural History, Complications and Prognosis

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