Traumatic brain injury

Definitions

Traumatic brain injury (TBI)

An alteration in brain function caused by an external force - a blow, a jolt, rapid acceleration or deceleration, a penetrating object, or blast - ranging from mild to severe.

Types of injury:

• Open (penetrating) head injury: the skull and dura are breached, exposing the brain
  • Increased risk of infection
• Closed head injury: the skull and dura stay intact, with no exposed brain; a non-penetrating skull fracture may still be present
  • Increased risk of raised intracranial pressure

Pathophysiology:

• Local brain injury
  • Damage to a specific region of the brain due to bruising, bleeding, laceration, or swelling
• Coup-countercoup injury
  • Injury at the point of impact (coup) and at the opposite side of the brain as it rebounds against the skull (countercoup)
• Diffuse axonal injury
  • Tearing of axons and small vessels due to the acceleration of the brain in the skull, leading to neuronal death
• Edema
  • Swelling of brain tissue after injury (vasogenic or cytotoxic edema), which raises intracranial pressure
• Hypoxic-ischemic injury
  • Loss of cerebral circulation, typically due to compromise of the cardiovascular and respiratory systems

Stratification of brain injury:

Brain injuries can be stratified into three categories: mild, moderate, and severe based on symptomatology present, using the Glasgow Coma Scale (GCS) - eye opening (1-4), verbal response (1-5), motor response (1-6), total 3-15; a score of 8 or less generally means coma or severe TBI.

• Mild TBI (i.e., concussion)
  • GCS score: 13-15
  • Loss of consciousness: 0-30 minutes
  • Alteration of consciousness: brief; up to 24 hours
  • Post-traumatic amnesia: <1 day
  • Imaging: normal
  • Recovery: most recover fully within weeks to months; a subset have persistent post-concussive symptoms (headache, dizziness, mood changes), with the patient seen in an outpatient setting
• Moderate TBI
  • GCS score: 9-12
  • Loss of consciousness: >30 minutes; <24 hours
  • Alteration of consciousness: >24 hours
  • Post-traumatic amnesia: 1-7 days
  • Imaging: normal or abnormal
  • Recovery: potential to have full recovery of physical and cognitive function with intense rehabilitation in an inpatient rehabilitation or skilled nursing facility
• Severe TBI
  • GCS score: 8 or less
  • Loss of consciousness: >24 hours
  • Alteration of consciousness: >24 hours
  • Post-traumatic amnesia: >7 days
  • Imaging: normal or abnormal
  • Recovery: often long-term physical, cognitive, and behavioral impairment; outcomes vary widely, from home with assistance to long-term care

Definitions

Alteration of consciousness

Change in baseline perception, awareness, and mental functioning.

Post-traumatic amnesia

Inability to recall events occurring after injury.

Retrograde amnesia

Inability to recall events preceding the injury.

Imaging

CT is first-line acutely, since it quickly detects bleeding and fractures; MRI is more sensitive for diffuse axonal injury and is done later. A normal result in mild TBI means normal structural imaging.

Behavioral stratification of traumatic brain injury:

Rancho Los Amigos Cognitive Scale is utilized to classify behaviors through a predictable sequence. Individuals progress through levels in sequence but can plateau at any point. Level of behavior:

• Level I: No response
  • Cognitive assistance needed: total assistance with all cognitive functions
  • Response to stimuli: no response to sounds, sights, touch, or pain
  • Single-step commands: unable to follow single-step commands
  • Characteristics of level: individuals are typically in a comatose state
• Level II: Generalized response
  • Cognitive assistance needed: total assistance with all cognitive functions
  • Response to stimuli: inconsistent, non-purposeful, generalized response to stimuli
  • Single-step commands: unable to follow single-step commands
  • Characteristics of level: individuals in a vegetative state
• Level III: Localized response
  • Cognitive assistance needed: total assistance with all cognitive functions
  • Response to stimuli: localized response to stimuli
  • Single-step commands: may follow simple commands inconsistently and with a delay (e.g., close your eyes, squeeze my hand)
  • Characteristics of level: individuals within a minimally conscious state; able to inconsistently track objects and respond to their name
• Level IV: Confused, agitated
  • Cognitive assistance needed: maximal assistance for cognitive function
  • Response to stimuli: localized response
  • Single-step commands: unable to follow single-step commands
  • Characteristics of level: confused, combative, easily agitated, hypersexual behavior
• Level V: Confused, inappropriate
  • Cognitive assistance needed: maximal assistance for cognitive function
  • Response to stimuli: localized response
  • Single-step commands: able to follow simple commands consistently; difficulty with complex commands
  • Characteristics of level: confused, inappropriate behaviors (combative and hypersexual behaviors have subsided), severely impaired memory
• Level VI: Confused, appropriate
  • Cognitive assistance needed: moderate assistance for cognitive function
  • Response to stimuli: localized response
  • Single-step commands: able to follow single-step commands
  • Characteristics of level: confused but behaviors are appropriate (goal-directed); no combative characteristics
• Level VII: Automatic, appropriate
  • Cognitive assistance needed: minimal assistance for cognitive function
  • Response to stimuli: localized response
  • Single-step commands: able to follow single-step commands
  • Characteristics of level: improved carryover with activity, minimal assistance for learning new tasks, superficial awareness of their condition but still unaware of specific impairments and safety limits
• Level VIII: Purposeful and appropriate
  • Cognitive assistance needed: stand-by assistance for cognitive function
  • Response to stimuli: localized response
  • Single-step commands: able to follow single-step commands
  • Characteristics of level: able to integrate new and old memory into making decisions, able to make adjustments to behavior in social interaction with minimal assistance

PTA role: The PT evaluates and sets the plan; the PTA collects data (behavior, vital signs, response to commands), carries out interventions at the current Rancho level, and reports changes in level, new deficits, or decreased arousal to the PT. The PTA doesn’t reassign the level or change the goals.

Intervention implications by level:

• Level IV: calm, low-stimulation environment; redirect rather than restrain; short, familiar sessions.
• Levels V-VI: simple, consistent commands and repetition to support memory.
• Levels VII-VIII: safety supervision for community tasks; build awareness of deficits.

Stop and notify the PT or nursing: signs of rising intracranial pressure (decreasing consciousness, worsening headache, vomiting, pupil changes, or Cushing’s triad, a late sign: rising systolic pressure with a widening pulse pressure, a slowing heart rate, and irregular breathing), a new neurological deficit or seizure, worsening concussion symptoms with activity, or escalating agitation at level IV, where you reduce stimulation rather than push the task.

Example: Identifying the Rancho level

A patient is restless, pulls at IV lines, and follows no commands, becoming combative during transfers.

Answer: Level IV: confused, agitated - not level V, since level V requires consistently following simple commands and combativeness has usually subsided by then. PTA approach: quiet, low-stimulation room, short sessions with familiar tasks, avoid restraining unless safety requires it, and report the behavior to the PT.