Module 5 GQ's

• Traumatic brain injury (TBI)

  Alteration in brain function, or other evidence of brain pathology caused by an external force
• Populations more likely to sustain a TBI

  • People 75 years and older
  • Men (adolescents and young adults)
  • American Indian
  • Alaska native
• Leading causes of TBI

  • Falls
  • Motor vehicle accidents
  • Being hit by or colliding with an object
  • Assault
• Open head injuries


  • With a skull fracture
  • Penetrating objects
  • Dura is open
  • Meninges are breached
  • Brain is exposed
  • Localized focal lesions
  • Direct cellular and vascular damage
  • Secondary damage due to injuries to the face and neck
• Closed head injuries


  • Without a skull fracture
  • Dura and skull intact
  • Brain forced into contact with the hard, bony outer covering of the skull
  • Acceleration-deceleration injury
  • Focal, multifocal, and diffuse lesions
• Characteristics of mild traumatic brain injuries

  • Loss of consciousness: <= 30 min
  • Alteration of consciousness: brief to 24 hours
  • Post-traumatic amnesia: < 0 to 1 day
  • Glasgow Coma Scale: 13 to 15
  • Neuroimaging: normal
  • Post concussion syndrome: poor cognitive function, difficulty with concentration and irritability
  • Chronic traumatic encephalopathy: due to repeated mild TBI's during recovery period after previous injury
• Characteristics of moderate traumatic brain injuries

  • Loss of consciousness: > 30 minutes < 24 hours
  • Alteration of consciousness: > 24 hours
  • Post-traumatic amnesia: > 1 to < 7 days
  • Glasgow Coma Scale: 9 to 12
  • Neuroimaging: normal or abnormal
• Characteristics of severe traumatic brain injuries

  • Loss of consciousness: > 24 hours
  • Alteration of consciousness: > 24 hours
  • Post-traumatic amnesia: > 7 days
  • Glasgow Coma Scale: < 9
  • Neuroimaging: normal or abnormal
• Primary injury


  • Due to direct trauma to the parenchyma
• Secondary injury


  • Cascade of biomechanical, cellular and molecular events that evolved over time due to initial injury and injury-related hypoxia, edema, and elevated intracranial pressure
• Contusions


  Bruising of the brain surface; local area of edema and small capillary hemorrhages
• Lacerations


  Tearing of the pia or arachnoid matter or brain tissue
• Types of intracranial hematomas or hemorrhages

  • Subdural hematomas
  • Epidural hematoma
  • Subarachnoid hemorrhage
  • Intraventricular hemorrhage
• Diffuse axonal injury


  Rapid rotational and linear acceleration and deceleration of the brain causing shear, tensile, and compression forces within the brain injuring axons (stretching, tearing) disrupting nerve communication
• Excitotoxicity and oxidative stress

  • Excessive releases of glutamate, dopamine and norepinephrine
  • Excessive glutamate leads to influx of Na+ and Ca++ into the cell with subsequent cellular edema and contraction of the extracellular space
  • Stimulates reactive oxygen species production which are detrimental to neurons attacking the cell membrane and degrading other key cellular components leading to cell death
• Increased intracranial pressure


  • TBI alters permeability of the blood-brain barrier
  • Swelling of the brain or intracranial hematoma & distortion & shift and brain herniations
  • Acute hydrocephalus caused by accumulation of blood in the ventricular system expanding the ventricles
  • Lead to changes in Pco2 & nervous tissue death
• Cerebral hypoxia or ischemia


  • Due to ruptured or compressed blood vessels
  • Lack of blood to the brain: relative reduction in cerebral blood flow
  • Lack of oxygen in the blood due to airway obstruction or chest injuries
• Intracranial hemorrhage


  • Hypoxia to brain tissues fed by hemorrhaging blood vessels
  • Increases pressure and distortion to brain tissue
  • Brain tissues is bathed in metabolic products from the damaged cells and blood
  • Immediate cell death from ischemia, edema, necrosis and toxic effects of blood on neural tissue
• Infections in the brain


  • Open wounds due to penetrating brain injuries
  • Prolonged invasive monitoring such as ICP monitoring
  • Infection in the brain tissue can cause swelling and cell death
• Seizures


  • Due to pressure or scarring
  • Can cause additional brain damage due to high oxygen and glucose requirements
• Electrolyte and acid-base imbalances

  Secondary cell death occurs via necrosis (swelling and then bursting of the cellular membrane) and apoptosis (destruction from within the cell through changes in DNA)
• Coma


  • Condition of being unarousable
  • No response to strong stimuli, including strong pinching of the Achilles tendon
• Vegetative state


  • Complete loss of consciousness, without alternation of vital functions
  • Spontaneous eye opening
  • Regular sleep/wake cycles
  • Normal respiratory patterns
  • Loss of tissue in subcortical, thalamic, and brainstem regions
• Minimally conscious state


  • Severely altered consciousness with at least one behavioral sign of consciousness
  • Following simple commands
  • Gestural or verbal yes/no responses
  • Intelligible speech
  • Movements or affective behaviors that are not reflexive
  • Loss of tissue in subcortical, thalamic, and brainstem regions
• Posttraumatic confusion


  Person being awake most of the time but is confused, easily distractable with faulty memory, and with slowed but consistent responses to stimuli
• Amnesia


  Loss of declarative memory and is divided into two aspects, retrograde amnesia and anterograde amnesia
• Retrograde amnesia


  • May prevent patients from knowing their family members, friends and information that defines who they are such as occupation and likes and dislikes
  • Procedural and semantic memories are typically unaffected or more mildly affected
• Anterograde amnesia


  • Prevents new memory accrual, including memory for those providing the patient's care, the location of care and the ability to verbalize what events or activities occurred previously, earlier in the day or over preceding days
  • Procedural learning can occur
• Post-traumatic amnesia


  Persons emerging from coma after moderate to severe TBI progress through vegetive state to a gradual reemergence of responsiveness and severe confusion, memory disruption and abnormal behaviors such as agitation, disinhibition and altered mood
• Effects of TBI on consciousness

  • May be impaired temporarily or for a prolonged period
  • Often have difficulty directing attention (distractibility) and attending to several things simultaneously
• Effects of TBI on personality

  • Decreased goal-behavior (executive functions) if lateral prefrontal cortex is involved
  • Impulsiveness and other inappropriate behaviors if ventral prefrontal cortex is damaged
  • Lower tolerance for frustration
  • Emotional lability
• Effects of TBI on cognition and memory

  • Slow mental processing
  • Decreased cognitive flexibility
  • Delusions
• Effects of TBI on communication

  • Disorganized and tangential oral or written communication
  • Imprecise language
  • Word-retrieval difficulties
  • Disinhibited and socially inappropriate language
• Effects of TBI on sensory, motor and visual functions


  • Sensory may be impaired
  • Perseveration of movements
  • Degree of motor impairment depends on severity of injury
  • Paresis/paralysis, apraxia, spasticity, contracture, lack of coordination, balance, posture, gait, speech, swallowing and eye movement disorders
  • Decreased acuity, field cuts, visual neglect or inattention
• Effects of TBI on autonomic functions

  • Problems with autonomic regulation secondary to damage to or compression of the brainstem and/or hypothalamus
  • Paroxysmal sympathetic hyperactivity
• Common medical complications after TBI

  • Post traumatic seizures
  • Deep vein thrombosis
  • Heterotopic ossification
  • Pressure ulcers
  • Pneumonia
  • Chronic pain
  • Contractures
  • Depression
• Glasgow Coma Scale


  Performed either at the prehospital stage or in the emergency department to test the function of the brainstem and cerebrum through eye, motor and verbal response
• Glasgow Coma Scale scores

  • 13 to 15: mild brain injury
  • 9 to 12: moderate brain injury
  • 8 or less: severe brain injury
• Categories assessed in Glasgow Coma Scale

  • Eye
  • Motor
  • Verbal
• Decompressive craniotomy


  • Large portion of the skull is removed to allow the brain to swell
  • Used when intracranial pressure is elevated for 25 mm Hg for 1 to 12 hours despite other medical interventions