Mild Traumatic Brain Most prevalent TBI Often overlooked at time of - PDF document

3/10/2012 Mild TBI Mild Traumatic Brain • Most prevalent TBI • Often overlooked at time of injury Injury • 15% develop longstanding (>1yr) symptoms Tarvez Tucker, M.D. Neurocritical Care Fellow • Post-concussive syndrome University of Cincinnati 6 th Annual Northern Kentucky TBI Conference March 23, 2012 www.bridgesnky.org Mild TBI: Cause Symptoms • Forceful motion of the head or impact • Lability (irritability, easily tearful) • Brief change in mental status • Depression – Confusion, disorientation, amnesia • Seizures, Fatigue, Headaches, Visual • Anterograde and retrograde amnesia Disturbances, Memory Loss, Poor – No loss of autobiographical information Attention/Concentration • Loss of consciousness for < 30 minutes • Sleep Disturbance • Dizziness/Loss of Balance • Emotional Concussion SECONDARY INJURY • From Latin concutere “to shake violently” Paramount to therapy – Avoidance of hypotension and hypoxemia • Most common type of traumatic brain – Incorporate other maneuvers to avoid increased injury intracranial pressure (ICP) and optimize • Epidemiology cerebral blood flow – 6 per 1000 people – Sports injuries, bicycle accidents, MVAs, falls, military (combat and civilian) (IEDs) 1

3/10/2012 Classic Concussion Skull Fractures • Transient loss of consciousness • Clinical signs • Normal head CT – Retroauricular ecchymosis (Battle’s sign) • Nausea, vomiting, and headache – Periorbital ecchymosis (raccoon eyes) • Post-concussion syndrome – Amnesia for events of injury • Complications – VIIth nerve palsy – Memory difficulties – CSF leaks – Dizziness • Rhinorrhea – anterior skull – Nausea and vomiting base • Otorrhea – mid-skull base – All lasting days to weeks • NG Tubes ??? Concussion: Grading Scales Concussion: Symptoms • Headache • Grade I – Migraine, tension-type – Amnesia < 30 min • Loss of motor coordination – Confusion, No LOC – Ataxia, imbalance, diplopia – Symptoms < 15 min • Seizures • Grade II – Early: not predictive of epilepsy – Amnesia > 30 min, LOC < 5 min • “convulsive syncope” – brief immediate sz • Grade III • Cognitive – Amnesia > 24 hr, LOC > 5 min – Confusion, difficulty focusing (perplexed) Mechanisms Blast-Related TBI • Rapid acceleration/deceleration • Improvised Explosive Devices • Impulsive force: head strikes immoveable – Signature injury of OEF and OIF – Homemade to sophisticated weaponry/high object/ rotational force grade explosives • Blunt trauma • 65% of severe TBI is explosion-related; ½ • Explosive force of all TBI is non-combat related • Mild TBI probably underdiagnosed 2

3/10/2012 Blast-Related TBI Blast Trauma • Blast overpressure wave – vacuum – • Clinical markers, GCS, duration of second positive pressure wave – return to amnesia, ongoing headache atmospheric pressure • “dazed,” seeing stars, brief disorientation: • Brain within the rigid cranial vault Due to blast exposure or shock of the – Shear forces event – Rapid accel/decel of the head • Initial CT normal: deterioration over 48 – Tissues at risk: of different density hours • Lung, GI tract • White and gray matter of the brain/fluid and cell – Consider MRI bodies Mild TBI in Veterans TBI in Veterans • Cross-sectional study of 2235 OEF/OIF • PTSD - improbable if amnestic for the veterans who had left combat theaters by event Sept 2004 – However, affective responses may be – 12% reported history consistent with mTBI on encoded at an unconscious level – Reconstruction of events from secondary the 3-Item Brief Traumatic Brain Injury Screen • Alteration, but not loss of consciousness sources may influence the development of sx – 11% screened positive for PTSD – Medical procedures at the scene, sights are psychologically traumatic TBI in Veterans Treatment in the Military • Military combat: a series, not a single, life- • Mild TBI not reported as a cause of threatening or traumatic event psychiatric evacuation during OEF and OIF (emotional disorders have) • PTSD more often associated with mild • Subtle deficits in performance in a highly than severe TBI – Limited encoding of event may be protective demanding occupation; self and others at risk • Reluctance to self-report mental health problems 3

3/10/2012 Outcome Outcome • Rehabilitation for functional recovery • mTBI worsens executive deficits associated with PTSD • Social support • Memories may be less amenable to • Younger age beneficial effective self-management • Disfigurement, chronic pain, ear/vestibular damage and psychiatric illness complicate • mTBI: damage to amygldala: emotion/fear recovery center and pre- frontal cortex: “check” • Sequelae of TBI and psychological trauma inhibitory center overlap and are hard to distinguish VA Hospitals Anatomy • DoD and VA healthcare screening • Vulnerable areas of the brain – Midbrain/diencephalon • Optimal context for healthcare delivery – Brainstem – Primary care, mental health, rehabilitation – White-gray junction centers • Compensation and pension issues – White matter tracts • Corpus callosum – Temporal and frontal lobes • Personality change, cognitive function, seizures Pathophysiology Concussion: Pathoanatomy • Drop in cerebral blood flow • Original theories • Excitatory neurotransmitters – Loss of physiological/metabolic function without structural change – Glutamate • Current: cellular and structural damage – Calcium influx: hyperexcitable neurons • Neuroimaging – Hypermetabolic state: elevated glucose needs • Alteration in the BloodBrainBarrier – Conventional: normal – Advanced MRI: abnormalities – Vulnerable to hypoxia, ICP • Diffuse axonal injury 4

3/10/2012 Mild TBI: Definitions Diagnosis • LOC < 30 minutes • Initial duration of LOC, amnesia • Post-traumatic amnesia <24 hours • Neuropsychological tests • Glasgow Coma Scale >12 – Athletes: baseline scores cf post-impact • Symptoms of concussion/ Mild TBI • Mild TBI – May include SDH, ICH, EDH Diagnosis in Athletes Diagnosis • Standard Assessment of Concussion • Balance, ability and reaction time – Questions of orientation, memory and – Visual and vestibular systems concentration – Romberg, finger-nose-finger, rapid alternatinh – Decline immediately post impact as compared movements to baseline – Stances on firm and foam surfaces – Improvement in 15 minutes and further • Eye movement normalization in 48 hours – Single digit numbers on test cards • Rec: symptom-free for 7 days prior to • Assesses eye movement, attention return to play Recommendations for Athletes Caution !!! • American Academy of Neurology • Glasgow Coma Scale < 15 (nl) • Focal symptoms or findings • Persistent headache, vomiting, increasing confusion, seizures, unequal pupil size • Confounding factors – Intoxication – Age > 60 or < 16 • “Talk and die” 5

3/10/2012 Cranial Imaging Advanced Imaging Techniques • A normal neurological examination doesn’t • MRI with GRE ensure absence of an intracranial lesion – Detects microbleeds • Skull fracture may dissipate impact energy • Diffusion Tensor Imaging – Depressed or basilar skull fractures may be – Shear injury to white matter tracts predictive • PET Scan / MRI Spectroscopy • If 16 – 65 yo, no external injury or basilar – Measures brain metabolites skull fx, normal exam: need for NSG is <1% PTSD Multiple Impact • Symptoms may be identical • “Dementia pugilistica” • Symptoms persist for months/years • “Second - impact” Syndrome following injury – Rare: second mild injury in children – • Trauma, especially to the vulnerable massive cerebral edema • Traumatic encephalopathy frontal/temporal lobes may make cognitive dysfunction more likely/identifiable • “sub - concussive” injury: soccer heading the ball Prevention Prevention • Mechanical • Snowboarding and skiing – Seat belts, airbags, helmets, stair rails, – Helmets: facial and soft tissue injury thin/flat shoes with hard soles • Contact sports • Athletes – Mouthguards role in dental and orofacial – “Head Impact Telemetry System” placed in injury helmets • Equestrian, cycling, motor sports – Barring head- down tackles or “spearing” – Helmets 6