What is Traumatic Brain Injury?
Traumatic brain injury (TBI), a form of acquired brain injury, occurs when a sudden trauma causes damage to the brain. TBI can result when the head suddenly and violently hits an object, or when an object pierces the skull and enters brain tissue. Symptoms of a TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. A person with a mild TBI may remain conscious or may experience a loss of consciousness for a few seconds or minutes. Other symptoms of mild TBI include headache, confusion, lightheadedness, dizziness, 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, and trouble with memory, concentration, attention, or thinking. A person with a moderate or severe TBI may show these same symptoms, but may also have a headache that gets worse or does not go away, repeated vomiting or nausea, convulsions or seizures, an inability to awaken from sleep, dilation of one or both pupils of the eyes, slurred speech, weakness or numbness in the extremities, loss of coordination, and increased confusion, restlessness, or agitation.
Is there any treatment?
Anyone with signs of moderate or severe TBI should receive medical attention as soon as possible. Because little can be done to reverse the initial brain damage caused by trauma, medical personnel try to stabilize an individual with TBI and focus on preventing further injury. Primary concerns include insuring proper oxygen supply to the brain and the rest of the body, maintaining adequate blood flow, and controlling blood pressure. 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-rays to check for bone fractures or spinal instability. For moderate to severe cases, the imaging test is a computed tomography (CT) scan. Moderately to severely injured patients receive rehabilitation that involves individually tailored treatment programs in the areas of physical therapy, occupational therapy, speech/language therapy, physiatry (physical medicine), psychology/psychiatry, and social support.
What is the prognosis?
Approximately half of severely head-injured patients will need surgery to remove or repair hematomas (ruptured blood vessels) or contusions (bruised brain tissue). 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 individual. Some common disabilities include problems with cognition (thinking, memory, and reasoning), sensory processing (sight, hearing, touch, taste, and smell), communication (expression and understanding), and behavior or mental health (depression, anxiety, personality changes, aggression, acting out, and social inappropriateness). More serious head injuries may result in stupor, an unresponsive state, but one in which an individual can be aroused briefly by a strong stimulus, such as sharp pain; coma, a state in which an individual is totally unconscious, unresponsive, unaware, and unarousable; vegetative state, in which an individual is unconscious and unaware of his or her surroundings, but continues to have a sleep-wake cycle and periods of alertness; and a persistent vegetative state (PVS), in which an individual stays in a vegetative state for more than a month.
What research is being done?
The National Institute of Neurological Disorders and Stroke (NINDS) conducts TBI research in its laboratories at the National Institutes of Health (NIH) and also supports TBI research through grants to major medical institutions across the country. This research involves studies in the laboratory and in clinical settings to better understand TBI and the biological mechanisms underlying damage to the brain. This research will allow scientists to develop strategies and interventions to limit the primary and secondary brain damage that occurs within days of a head trauma, and to devise therapies to treat brain injury and improve long-term recovery of function.
More information about Traumatic Brain Injury (TBI) Research is available at: http://www.ninds.nih.gov/research/tbi/index.ht
Concussion
A concussion is a traumatic brain injury (TBI) that may result in a bad headache, altered levels of alertness, or unconsciousness. It temporarily interferes with the way the brain works, and it can affect memory, judgment, reflexes, speech, balance, coordination, and sleep patterns.
Concussions and Head Injuries
The brain normally floats inside the skull, cushioned gently by the surrounding spinal fluid. The brain consists of a gelatin-like substance and is vulnerable to outside trauma. The skull protects the brain against trauma, but does not absorb all the impact of a violent force.
An abrupt blow to the head, or even a rapid deceleration, can cause the brain to bounce against the inner wall of the skull. There is a potential for tearing of blood vessels, pulling of nerve fibers and bruising of the brain substance.
Sometimes the blow can result in microscopic damage to the brain cells without obvious structural damage visible on a CT scan. In severe cases, the brain tissue can begin to swell. Since the brain cannot escape the rigid confines of the skull, severe swelling can compress the brain and its blood vessels, and limit the flow of blood. Without adequate blood flow, the brain does not receive the necessary flow of oxygen and glucose. A stroke can occur. Brain swelling after a concussion has the potential to amplify the severity of the injury.
A blow to the head can cause a more serious initial injury to the brain. A contusion is a bruise of the brain involving bleeding and swelling in the brain. It can be thought of as a bruise of the brain tissue.
A skull fracture occurs when the bone of the skull breaks. A skull fracture by itself may not necessarily be a serious injury. Sometimes, however, the broken skull bones cause bleeding or other damage by cutting into the brain or its coverings.
A hematoma is a blood clot that collects in or around the brain. If active bleeding persists, hematomas can rapidly enlarge. Like brain swelling, the increasing pressure within the rigid confines of the skull due to an enlarging blood clot can cause serious neurological problems and even be life-threatening. Some hematomas are surgical emergencies. Hematomas that are small sometimes can go undetected initially, but may cause symptoms and require treatment several days or weeks later. The warning signs of a serious brain injury are:
Seek immediate medical attention if any of these warning signs occur.
Grading Concussions
There is no universal agreement on the grades of severity for a concussion. There are many different guidelines for concussion evaluation and return-to-play decisions in athletes. Most guidelines recognize three different grades of concussions and share similar recommendations for return to play.
The two sets of guidelines most followed in the U.S. were formulated by the American Academy of Neurology (AAN) and Robert C. Cantu, MD.
In 1986, Cantu formulated a set of guidelines that became widely used; these were subsequently adopted by the American College of Sports Medicine (ACSM). In 1991, the Colorado Medical Society Guidelines were formulated in response to several deaths related to head injuries in Colorado high school football players. These guidelines are more restrictive than previous versions and were subsequently adopted by the National Collegiate Athletic Association (NCAA). More recently, the AAN proposed another set of guidelines. Currently, there is no consensus within the sports medicine community as to which set of guidelines is the most appropriate.
Grading the concussion is a helpful tool in the management of the injury (see Cantu, below) and depends on: 1) presence or absence of loss of consciousness, 2) duration of loss of consciousness, 3) duration of posttraumatic memory loss, and 4) persistence of symptoms, including headache, dizziness, lack of concentration, etc.
Some team physicians and trainers evaluate an athlete’s mental status by using a five-minute series of questions and physical exercises known as the Standardized Assessment ofConcussion (SAC). This method, however, may not be comprehensive enough to pick up subtle changes.
The Centers for Disease Control (CDC) offers a Concussion Tool Kit. It also offers a Heads Up Concussion in Youth Sports online training course for coaches.
According to the Cantu Guidelines, Grade I concussions are not associated with loss of consciousness, and post-traumatic amnesia is either absent or less than 30 minutes in duration. Athletes may return to play if no symptoms are present for one week.
Players who sustain a Grade II concussion lose consciousness for less than five minutes or exhibit posttraumatic amnesia between 30 minutes and 24 hours in duration. They also may return to play after one week of being asymptomatic.
Grade III concussions involve post-traumatic amnesia for more than 24 hours or unconsciousness for more than five minutes. Players who sustain this grade of brain injury should be sidelined for at least one month, after which they can return to play if they are asymptomatic for one week.
Following repeated concussions, a player should be sidelined for longer periods of time and possibly not allowed to play for the remainder of the season.
NCAA Update
The NCAA’s 2011-2012 Sports Medicine Handbook includes a section called “Concussion or Mild Traumatic Brain Injury (mTBI) in the Athlete,” which notes that “In the years 2004 to 2009, the rate of concussion during games per 1,000 athlete exposures for football was 3.1; for men’s lacrosse, 2.6; for men’s ice hockey, 2.4; for women’s ice hockey, 2.2; for women’s soccer 2.2, for wrestling, 1.4; for men’s soccer, 1.4; for women’s lacrosse, 1.2; for field hockey, 1.2; for women’s basketball, 1.2; and for men’s basketball, 0.6, accounting for between four and 16.2 percent of the injuries for these sports, as reported by the NCAA Injury Surveillance Program by the Datalys Center.” The NCAA defines concussion or mild traumatic brain injury as “a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces.”
The handbook also states that “NCAA member institutions must have a concussion management plan for their student-athletes on file with specific components as described in Bylaw 3.2.4.16 (see Guideline 2i).” The plan:
Causes, incidence, and risk factors
A concussion may result when the head hits an object or a moving object strikes the head.
A concussion can result from a fall, sports activities, and car accidents. Significant movement of the brain (called jarring) in any direction can cause loss of alertness (become unconscious. The length of unconsciousness may be a sign of the severity of the concussion. However, concussions don’t always involve a loss of consciousness. Most people who have a concussion never black out. A patient can have a concussion and not realize it.
Factors that may increase risk of a concussion include:
Symptoms
Symptoms of a concussion can range from mild to severe. They can include:
The following are emergency symptoms of a concussion. Immediate medical care is required if there are:
Head injuries that result in concussion often are associated with injury to the neck and spine. Particular care should be exercised when moving patients who have had a head injury.
While recovering from a concussion, the patient may:
Signs and tests
The doctor will perform a physical exam and check the nervous system. There may be changes in pupil size, thinking ability, coordination, and reflexes.
Tests that may be performed include:
Treatment
A concussion with bleeding or brain damage must be treated in a hospital.
If the concussion occurred during a sporting event and resulted in a headache, confusion, or change in alertness, a trained person must determine when that person can return to playing sports.
Children with concussion symptoms should avoid sports and from being overly active during recess, physical education classes, and other playtimes. When a person can safely return to normal activities depends on the severity of the concussion. Some may need to wait 1 to 3 months or longer. Return-to-play decisions are individual and based on recovery, time without symptom and other factors.
Some organizations recommend that in a child who had a concussion, that child avoid sports activities that could produce a similar head injury for the rest of the season.
Treatment for a concussion may include:
Expectations (prognosis)
Healing or recovering from a concussion takes time. It may take days, weeks, or even months. The patient may be irritable, have trouble concentrating, be unable to remember things, have headaches, dizziness, and blurry vision. These problems will probably go away slowly.
Complications
Complications from a concussion can include:
The second impact syndrome (SIS) is when a person gets a second concussion while still having symptoms from a first one. Second-impact syndrome results from acute, often fatal brain swelling that occurs when a second concussion is sustained before complete recovery from a previous concussion. This is thought to cause vascular congestion and increased intracranial pressure, which can occur very rapidly and may be difficult or impossible to control. The risk of second-impact syndrome is higher in sports such as boxing, football, ice or roller hockey, soccer, baseball, basketball and snow skiing.
The CDC reports an average of 1.5 deaths per year from sports concussions. In most cases, a concussion, usually undiagnosed, had occurred prior to the final one.
People who suffer a head injury may suffer from side effects that persist for weeks or months. This is known as postconcussive syndrome. Symptoms include memory and concentration problems, mood swings, personality changes, headache, fatigue, dizziness, insomnia and excessive drowsiness. Patients with postconcussive syndrome should avoid activities that put them at risk for a repeated concussion. Athletes should not return to play while experiencing these symptoms. Athletes who suffer repeated concussions should consider ending participation in the sport.
Chronic Traumatic Encephalopathy:
This is a syndrome that was first recognized in boxers in the 1920’s (dementia pugilistica). The symptoms of CTE are insidious, and may appear years or even decades after the TBI causing the symptoms. CTE is first manifested as deteriorations in memory, attention and concentration. Often episodic disorientation, dizziness and headaches are also reported. Wit progressive deterioration, additional symptoms are seen: lack of insight, poor judgment, poor to little impulse control and in the final stages, overt dementia is seen. Severe cases can also be accompanied by slowing of muscular movements, marked facies, propulsive gait, impeded speech, tremors, vertigo and deafness. Corsellis, et. al. (The Aftermath of Boxing, Psycol Med 1973 (3:270-303)) has postulated a 3 stage progression for the disease: Stage 1 manifests by affective disturbances and psychotic symptoms. Stage 2 is characterized by social instability, erratic behavior and the initial stages of Parkinson’s disease. Stage 3 consists of general cognitive dysfunction progressing to full blown dementia, full Parkinson’s disease as well as speech and gait abnormalities, and dysarthria, dysphagia and ocular abnormalities.
The severity of the disorder appears to correlate with the length of time the sport is played (the number of TBI suffered) and it is unclear as yet if a single TBI can trigger the onset of TCE.
Diagnosis of CTE:
There are no biomarkers presently available for TCE, and pathological diagnosis is made on tissue studies of cadaveric brain. Positive CTE examinations reveal tau-immunoreactive dystrophic axons in white matter, reduction in brain weight, enlargement of the lateral and third ventricles, thinning of the corpus collusum, cavum septum pellucidum with fenestrations, and scarring and neuronal loss of the cerebellar tonsils.
Diagnosis in the living patient is made based on the above affective, psychological and observable physical signs and symptoms.
Prevention
Attention to safety, including the use of appropriate athletic gear reduces the risk of head injury. Also, return-to-play regimens must be developed with strict criteria for the evaluation of players who suffered TBI. Examinations of such players should be performed by qualified medical personnel, and a neurologist should always be consulted before any change in activity level is considered.
References
1. Ropper AH, Gorson KC. Clinical practice: concussion. N Engl J Med. 2007;356:166-172. [PubMed: 17215534]
2. Hunt T, Asplund C. Concussion assessment and management. Clin Sports Med. 2009;5-17. [PubMed: 19945584]
3. National Center for Injury Prevention and Control. Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious Public Health Problem. Atlanta GA: Centers for Disease Control and Prevention 2003.
4. MMWR Reports for 10.7.11: Nonfatal Traumatic Brain Inuries Related to Sports and Recreation Activities Among Persons Aged < 19 Years: Unites States, 2001-2009. Centers for Disease Control and Prevention
5. Omalu, B., et. al., Chronic Traumatic Encephalopathy in a National Football League Player, Neurosurgery 57:126-134 (2005)
6. McKee, A., et. al., Chronic Traumatic Encephalopathy in Athletes: Progressive Tauopathy following Repetitive Head Injury, J Neuropathol Exp Neurol. 2009 July; 68(7): 709-735
7. McKee, A., et. al., TDP-43 Proteinopathy and Motor Neuron Disease in Chronic Traumatic Encephalopathy, J Neuropathol Neurol. 2010 September; 69(9): 918-929.
8. McCrory, P.; Cantu,R.; et. al.; Consensus Statement on Concussion in Sport—the 3rd International Conference on Concussion in Sport held in Zurich, November 2008, (published in SAJSM Vol. 21 No 2 2009)
Internet Resources:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001802/
http://www.cdc.gov/traumaticbraininjury/tbi_ed.html
http://www.cdc.gov/concussion/HeadsUp/high_school.html
http://www.cdc.gov/concussion/clinician.html
http://www.neurosurgery.pitt.edu/trauma/concussion.html
http://www.aans.org/Patient%20Information/Conditions%20and%20Treatments/Concussion.aspx
http://www.nytimes.com/2009/12/21/sports/football/21concussions.html?pagewanted=all
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2945234/pdf/nihms131627.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951281/
http://www.nejm.org/doi/pdf/10.1056/NEJMp1007051
http://www.braininjuryresearchinstitute.org/about-us/