Traumatic Brain Injury Overview

Traumatic Brain Injury (TBI) Overview

• TBI is injury to the brain caused by external force
• TBI results from blunt or penetrating head injuries
• TBI results from rapid head movements causing back and forth movement inside the skull
• TBI is not caused by degenerative or congenital conditions

Causes of TBI in Vulnerable Populations

• Blow to the head with any object
• Strenuous shaking of the body
• Falling and hitting your head
• Being pushed against a wall or other solid object
• Being punched in the face
• Use of firearms
• Strangulation
• Near drowning

Scope of the Problem

• Approximately 2 million people sustain a brain injury annually
• Every 15 seconds, someone experiences a TBI
• TBI is the 4th leading cause of death overall
• Approximately 5,500 people sustain a TBI daily
• TBI is the leading cause of death until age 44

TBI by Age

• Peaks in incidence are seen in children under 5 years old, adolescents (15-24 years old), and adults over 70 years old
• Highest incidence is seen in 15-24 year olds (133 per 100,000)
• Highest incidence is seen in adults over 65 (165 per 100,000)

TBI by Gender

• Males are twice as likely to sustain a TBI compared to females
• Highest rate of injury is seen in males aged 15-24 years old

Mechanism of TBI

• Direct injury to brain tissue
• External forces applied to the outside of the skull, transmitted to the brain
• Movement of the brain inside the skull

Types of TBI

• Open head injury: Penetration of the skull, examples include severe falls, gunshot wounds, assault, and vehicle accidents
• Closed head injury: No open head wound, internal brain damage resulting from falls, vehicle accidents, or sports accidents

Closed Head Injuries - Types

• Hyperextension: Sudden backward acceleration of the head and neck, leading to the brain striking the front of the skull.
• Hyperflexion: Head recoils forward and suddenly stops, leading to impact of the occipital brain against the back of the skull.

TBI Mechanisms & Injury Types

• Contact phenomena: Resulting in focal lesions
• Acceleration/Deceleration: Primarily causing diffuse axonal injury (DAI)

Types of Traumatic Brain Injury

• Direct Impact Injury: Damage occurs directly under the point of impact
• Acceleration-Deceleration Injury: A bouncing effect causing impact on the opposite side of the head.

Two Varieties of Injury: Focal and Diffuse

• Focal Injury: Injury highly concentrated in a specific area; commonly from open head injury or brain penetration; easy to identify using medical imaging; symptoms closely related to functions in the affected brain area
• Diffuse Injury: Injury not in a specific area; usually from closed head trauma; difficult to detect; symptoms may not be immediately evident

Types of TBI Damage (Pathophysiology)

• Primary Injury: Occurs immediately due to trauma; includes contusion, damage to blood vessels, and axonal shearing. The blood-brain barrier and meninges may be damaged; neurons may die.
• Coup-Countereocoup Injury: Localized damage to the brain under the point of impact. Damage can occur on the opposite side of the impact from the brains bouncing.
• Secondary Injury: Develops hours or days after the trauma; impacts previously undamaged parts of the brain. Important causes include changes in blood flow (ischemia - insufficient blood flow, cerebral hypoxia, hypotension), cerebral edema (swelling), and increased intracranial pressure, leading to possible brain herniation

Levels of Increased Intracranial Pressure (ICP)

• Normal: 5-15mmHg
• Mild: 16-20mmHg
• Moderate: 21-30mmHg
• Severe: 31-40mmHg
• Very Severe: 41+mmHg

Severity of TBI

• Moderate-to-Severe TBI: 15% of all cases; typically hospitalized; characterized by documented loss of consciousness, potentially skull fractures, periods of coma, loss of memory (post-traumatic amnesia) for a time period, and chronic changes in cognitive, physical, and behavioral function
• Mild TBI (Concussion): 85% of all cases; often seen in emergency rooms or doctors' offices; characterized by headaches, dizziness, slowed processing, forgetfulness, fatigue, and sensitivity to noise/light; in most cases, full recovery occurs within 3-6 months. In 15% of cases chronic symptoms that significantly interfere with daily function persist

Common Problems after TBI

• Physical: Sleep disturbance, headaches, sense changes, seizures, loss of motor skills, digestive issues, fatigue, coordination and balance issues
• Cognitive: Repeating things, forgetfulness, attention issues, impaired orientation in time/place, difficulty communicating, and difficulty processing information
• Behavioral: Apathy, mood swings, personality changes, impulsivity, anxiety, depression, increase or decrease in appetite, changes in social skills, flat or constricted affect
• Neuromuscular: Abnormal tone, paresis/paralysis, impaired balance, sensory impairments
• Communication: Difficulty finding words/naming objects, receptive/fluent aphasia (temporal lobe), expressive/non-fluent aphasia (frontal lobe), dysarthria (cerebellum), impaired reading/writing comprehension

Cognitive Changes in "Executive Functioning"

• Difficulty planning/setting goals
• Problems being organized
• Difficulty being flexible
• Difficulty problem-solving, prioritizing, insight, and safety awareness

Communication Deficits

• Impaired pragmatics
• Difficulty finding the right words/naming objects
• Receptive/fluent aphasia
• Expressive/non-fluent aphasia
• Dysarthria
• Impaired reading/writing comprehension

Emotional/Behavioral/Social Changes

• Depression
• Anxiety
• Increased impulsivity
• Irritability/agitation
• Socially inappropriate behavior
• Intolerance of others
• Rapid loss of emotional control
• Difficulty getting along with others
• Self-monitoring issues

Long-Term Challenges Post-TBI

• Vocational/school failure
• Family life/social relationships collapse
• Increased financial burden on families and social service systems
• Alcohol and substance abuse
• Chronic depression/anxiety