Traumatic Brain Injury (TBI) for Neurology Residents

– with a focus on concussion

Michelle-Lee JonesJune 8, 2011

Terminology

• Definition of TBI: – “Traumatic brain injury (TBI) is a nondegenerative,

noncongenital insult to the brain from an external mechanical force, possibly leading to permanent or temporary impairment of cognitive, physical, and psychosocial functions, with an associated diminished or altered state of consciousness”

(http://emedicine.medscape.com/article/326510-overview)

– Classification into mild, moderate and severe

Terminology• MILD: traumatically induced physiological brain

function disruption, with at least one of the following:

1. any period of LOC ≤ 30 mins2. posttraumatic amnesia (antero- or retrograde) not

greater than 24 hours3. any alteration in mental state (e.g. disoriented,

confused)4. focal neurological deficit(s), transient or not5. initial (GCS) score of 13 – 15

The American Congress of Rehabilitation Medicine (ACRM) definition of mild TBI

Terminology• Concussion = altered

function • mTBI = pathologic state of

the brain following the trauma,

• Above terms often used interchanegably

• AAN concussion grades:– Grade 1 - altered mental

status < 15minutes, no LOC– Grade 2 - altered mental

status > 15 minutes, no LOC– Grade 3 - any LOC

Terminology

Vienna Concussion in Sport Agreement Statement (for the NHL-NHLPA Concussion Program), from CMAJ, May 17, 2011, 183(8)

Terminology

• MODERATE:– GCS of 9 – 12– Usually associated with prolonged LOC, and/or

neurologic deficit

• SEVERE: – GCS ≤ 8 (obtunded or comatose)– Usually associated with significant neurologic

injury, with structural lesions on neuroimaging (e.g. skull fracture, ICH, cerebral edema)

Epidemiology

• In US, ≈ 1.7 million new TBI cases/yr with ≈ 52,000 deaths/yr

• Roughly 75% of all TBI cases are mild TBI and acute concussion

• Highest prevalence among males, kids < 4 years, adolescents (15 - 19 years) and adults >65 years

• The very young and old FALL while the adolescents succumb to sports-related injuries and motor vehicle accidents

Pathophysiology

• Two epochs of injury:– Immediate primary tissue damage due to the trauma

that results in deformation of the skull and CNS, e.g. skull fractures, ICH, contusions, penetrating wounds, hypoxic-anoxic injury, DAI, diffuse microvascular injury

– Secondary injury that quickly follows the primary phase and can last days-weeks with neuronal and glial damage, e.g. glutamate excitotoxicity; CBF cannot match the incr. metabolic demand; mitochondrial dysfunction.

What do these terms mean?

• Chronic traumatic encephalopathy (CTE): “permanent neurocognitive deficits follow recurrent trauma” e.g. dementia pugilistica in boxers

What do these terms mean?• Second Impact

Syndrome: rapid onset of cerebral oedema leading to severe neurological deficits (e.g. coma) when one suffers from another TBI before fully recovering from the previous one; fatality is near 50%

What do these terms mean?Post-concussive syndrome: Persistence of the following symptoms for more than a few days post trauma: headache, confusion, amnesia esp. short term, difficulty concentrating or multitasking, mood alteration, sleep disturbance, anxiety, vertigo (SOMATIC, COGNITIVE, EMOTION & BEHAVIOUR)

CMAJ, May 17, 2011, 183(8)

Clinical presentation - concussion

From AAN continuum – TBI Dec 2010

W/U & Managememt

• If suspected TBI, remove patient from site of injury, do MS and screening neurological exam

• if mild injury with no symptoms and normal neuro exam can resume activity

• If mild TBI detailed MS exam using specialized tests e.g. Military Acute Concussion Evaluation (MACE), Immediate Post-Concussion and Cognitive Testing (ImPACT) – Frontal tests esp!!

• Later on, formal neuropsychological testing

W/U & Managememt• For concussions, symptomatic treatment is

required – NSAIDs, SSRIs, rest, CBT, graduated return to play protocol

• If LOC ER, remember ABCs for mod-severe TBI• Indication for neuroimaging in the context of

trauma:– Signs and symptoms suggestive of structural lesions,

e.g. focal neurological signs and prolonged depressed level of consciousness

– CT and MRI usually normal for mild TBI – alternatively DTI, fMRI, MRS, PET

Neurology 1997;48;581(summary statement)Practice Parameter : The management of concussion in sports

Neurology 1997;48;581(summary statement)Practice Parameter : The management of concussion in sports

To be revised late 2011

K.M. Galetta, J. Barrett, M. Allen, et al. Neurology 2011;76;1456

• Study cohort = boxers and mixed martial arts fighters, n = 39, tested pre and post three sparring rounds

•The King-Devick (K-D) test measures the speed of rapid number naming (reading aloud single-digit numbers from 3 test cards), and incorporates testing of impairment of eye movements, attention and language

•MACE concurrently used in those with head trauma

•The K-D test was assessed as a potential rapid sideline screening for concussion (< 2 mins to administer)

RESULTS: •Postfight K-D scores were significantly worse for those with head trauma (59.1 ± 7.4 vs 41.0 ± 6.7 s, p < 0.0001); greatest drop in score for subjects with LOC that correlated well with post-fight MACE scores; good interrater reliability•Simple quick test but multiple confounders – e.g. lack of gold std/environment

Post traumatic headache (PTHA)

• Most common symptom following mild TBI (at least 70 % cases)

• 7 secondary headache syndromes for headaches attributed to head or neck trauma (ICHD-2):1. acute PTHA2. chronic PTHA3. acute headache attributed to whiplash injury4. chronic headache attributed to whiplash injury5. headache attributed to traumatic intracranial hematoma6. postcraniotomy headache7. headache attributed to other head or neck trauma

Post traumatic headache (PTHA) - classification

From AAN Continuum – TBI Dec 2010

Post traumatic headache (PTHA) - classification

From AAN Continuum – TBI Dec 2010

Post traumatic headache (PTHA)

• Risk factors for development of chronic PTHA:– Female gender, lower SES, prior history of

headaches, mild severity of head trauma, short duration of posttraumatic amnesia, medication overuse

• Pathophysiology:– Activation of the trigeminocervical complex, and

trigeminovascular system (like migraines)

Management of PTHA

From AAN Continuum – TBI Dec 2010

Post-traumatic epilepsy (PTE)

• Seizures following TBI are classified as:– immediate (within first 24 hours)– early (between 24 hours and 7 days)– late (after 7 days)

• Immediate and early are considered provoked seizures while late seizures that recur are indicative of underlying epilepsy

• Incidence PTE 4 – 53%

Post-traumatic epilepsy (PTE)

• Risk factors:– SEVERITY OF HEAD INJURY– early posttraumatic seizures– age > 65 years– brain contusion– intracerebral hematoma

• Up to 86% of those with first posttraumatic seizure will have a second within the following 2 years

Post-traumatic epilepsy (PTE)

Type of TBI Standardized Incidence ratio

Duration of increased risk/years

mild 1.5 5 moderate 2.9 10 severe 17 20

Annegers JF, et. al. A population-based study of seizure after traumatic brain injuries. NEJM 1998;338(1):20–24.

Management PTE

• AED not given for mild TBI unless PTE occurs• Prophylaxis with phenytoin for the 1st week

following trauma is indicated for severe TBI – no evidence of disease modification if given afterwards

• Same general principles apply as for Rx of ppl with epilepsy in general, trial of taper to consider if no sz x 2 yrs (remission rate 25 – 40%)

TBI - prognosis

• NOTE that the presence of LOC does not indicate TBI severity and is not a good predictor of recovery duration

• Longer periods of post traumatic amnesia and LOC suggest more severe injury

• Prospective case series of concussions over seven NHL regularseasons (1997–2004), n = 559 concussions• Primary outcome -> concussion, with documentation of consistent clinical features•Secondary outcome time loss

Results: •Estimated incidence of 1.8 concussions per 1000•Most common postconcussion symptom was headache (71%)•Time loss increased 2.25 times (95% confidence interval [CI] 1.41–3.62) for every subsequent (i.e., recurrent) concussion sustained during the study period•Significant predictors of time loss were postconcussion headache (p < 0.001), low energyor fatigue (p = 0.01), amnesia (p = 0.02) and abnormal neurologic examination (p = 0.01)•Headache (OR 2.17) and low energy or fatigue (OR 1.72) = significant predictors oftime loss of more than 10 days

TBI SUMMARY• TBI- classification as mild/moderate/severe• Concussion definition – graded neurological/psychosocial

impairment as a result of brain injury induced by biomechanical forces

• Post concussive syndrome somatic/cognitive/emotional& behavioral

• Work-up for mild TBI – initial evaluation and indications for neuroimaging

• King-Devick’s test – quick and easy, but complete?• PTHA and PTE are not uncommon – diagnosis and mgmt• Prognostication of TBI and long term sequelae

Case 1

17-year-old boy suffers a head injury doing a hockey game and has LOC x 4 minutes. He is “dazed” for 8 minutes after but is oriented and speaks normally. He cannot recall the collision that lead to his head injury or the injury itself, but remembers events prior to the game well. He eagerly wants to rejoin the game. You tell him…

Video Illustration

• http://sportsillustrated.cnn.com/video/nhl/2011/06//060711.gupta_nhl_concussions.mov.SportsI07llustrated/

Video Illustration

• http://www.youtube.com/watch?v=lnLQg5O0NZY/