NPch15 Traumatic Brain Injury Flashcards
Traumatic brain injury
An alteration in brain function or pathology due to external force
- Physical trauma
What are two types of TBI?
- Closed head injury (CHI)
- Penetrating head injury (PHI)
Acquired Brain Injury
Any type of damage to the brain that occurs after birth
- TBI is the most common type of ABI among people under 50 yrs
- Other aetiologies, like stroke belong under ABI
Epidemiology of TBI - how common is it?
- Most common cause of brain damage in children and young adults
- Recent data suggest approximately 85,000 people per year in the Netherlands (underestimate - many not hospitalised)
- Increasing rate of TBI in older people due to ageing population and higher survival rates
Incidence
- Peak ages: 15-24 yrs, first 5 yrs and elderly
- Men sustain TBIs twice as frequently as women (men engage in behaviours that result in TBI more often)
What are risk factors contributing to TBI?
- Lower SES, uneployment, and lower education (probably because of the behaviours these people engage in)
- Alcohol and substance abuse significantly contribute to TBI incidence (no enough reflexes to stop the fall, agression)
What are main causes of TBI?
Falls, transportation-related injuries (cars, motorbikes) and blows to the head caused by violence
What are long-term implications of TBI?
- Long-term mortality associated with age, lack of independence, and tube feeding
- Late-life dementing illnesses and neuropsychochiatric sequlae common
- Specific risks in retired athletes, e.g. rugby or American football
How can we distinguish between the different phases TBI is in, in regard to recovery?
- Acute phase (which lasts up to 1 month)
- The subacute phase (lasting up to 6 months)
- The chronic phase
Classification
How do we classify TBI based on severity? What are the different effects?
- TBI severity spectrum
- Mild impacts leave no lasting effects
- Severe TBIs can lead to prolonged coma and extensive brain damage
- Severity correlated with long-term social and cognitive effects
- Glasgow coma scale (GCS)
What is Glasgow Coma Scale? What are the 3 domains? How do you interpret the score?
- Used to test the spontaneous reaction of a patient to being addressed or having pain stimuli applied
↪ Helps mp the severity of impairments of consciousness (3-15 point scale) - Three domains:
1. Eye opening
2. Motor response
3. Verbal response - For each you can get a rating and based on that they decide the severity of the injury
- Low score = more severe, high score = less severe
- Criticism: when it is administered differs - not ideal to predict longer term outcomes = might be incorrect
What is Post-Traumatic Amnesia? How do we split in two types?
Post-Traumatic Amnesia - loss of memory due to TBI
- The moment of accident forms a dividing line between the two parts of PTA
1. Retrograde Amnesia
2. Anterograde Amnesia
Retrograde amnesia
Amnesia about the time prior to the accident and the accident itself
- over time, RA ‘shrinks’ and the remaining amnesia concerns the period shortly before the accident
↪ result of interruption in the consolidation process
Anterograde amnesia
Occurs after the accident, as a result of which new info cannot be stored
What is PTA predictive of? How is PTA correlated with severity of TBI?
- Duration of PTA often correlated with GCS but offers finer scalping
- PTA more predictive of long-term cognitive status and neuroimaging findings (compared to GCS)
- Most predictive of long-term cognitive status
- Helps determine the presence and severity of a TBI
- Increasing duration of PTA corresponds to more severe injury
What are some non-behavioural measures of TBI?
- Neuroimaging and electrophysiological measures like EEG used for damage assessment
- CT scans commonly used in acute stages for their cost-effectiveness and availability
- MRI is preferable in subacute (stable phase) and chronic stages for its predictive power
What is neuropathology of TBI?
- Effects develop over various timeframes, from mins to years
- Very complex to find the biomarker (changes over time - graph) so difficult to predict outcomes
- Nature of impairments depends on the timing of assessment
Penetrating head injuries
Causes of penetrating head injuries
- Leading cause: gunshot wounds
- But also, everyday objects like ball-point pens, chopsticks, door keys, etc
Penetrating head injuries
Mortality and severity
- PHI mortality 6.6 times higher than Closed Head Injury
- 36% dead on arrival or die in emergency unit
- 41% of admissions for survivable injuries die within first 48 hours
- 52% of survivors are severly affected
Penetrating head injuries
Types of injuries resulting in PHI
- Objects embedded in head (problematic: if you remove might cause imflammation which could result in epilepsy)
- '’Through-and-through’’ injuries: both entry and exit wounds
- Bone fragments often driven into the brain (tangential injury)
- affect how they present problems but also their extent of recovery
Penetrating head injuries
What does neuropathology asses in case of PHI? Why is it important to have this info?
The second question ties to the next flashcard
- Advanced imaging techniques show type and extent of PHI damage
- Key issues: penetration location, trajectory, fragment scattering
↪ Affects the behavioural outcome
Penetrating head injuries
What factors affect the outcome PHI is going to have?
- Physical qualities like speed, wobble, and malleability affect extent of damage
- The speed and physical qualities of the object is most closely associated with the extent of tissue damage
- High-velocity (>300 m/s) causes more extensive tissue damage (gunshot wounds)
↪ Immediate problems - Delayed effects like post-traumatic epilepsy and increased risk for cancer are associated with worse outcomes
↪ Long term problems
Penetrating head injuries
What could the tissue damage in PHI result in?
- Extensive blood loss can lead to hypotension and hypovolemia, worsening primary damage
- Local and general cerebral oedema and intracranial haematomas may develop
Penetrating head injuries
Neuropsychological effects
- Deficits depend on lesion site and clinical history (previous problems?)
- General impairments, including issues with attention and memory
- Short-term memory is especially likely to be compromised, regardless of injury location
- Larger lesions generally result in more widespread deficits
Penetrating head injury
How does PHI progress? What is permanent damaged and what improved with time?
- Rapid gains observed in the first year or two post-injury
- Further improvement is slow and mainly due to learned accommodations
- Cognitive impairments like language disorders may improve but sensory defects (lower level…?) like visual blind spots presist
- General effects of brain damage, such as distractibility, may improve but not return to pre-injury levels
Closed head injuries
Definition, consequences, stages of damage
- Non-penetrating injuries (falls, blunt head trauma etc.)
- CHI typically results in more generalised brain injury
- Damage occurs in stages: initial impact followed by secondary physiological processes
- Long-term effects can take months to years to fully develop (mainly in mild TBI because they often don’t become apparent immediately)
Closed head injuries
What are the factors that determine the extent of damage?
- Severity of injury dictates the extent of damage
- Biomechanics crucial in determining primary and secondary effects
Closed head injury - primary effects
What is Diffuse axonal injury (shearing)? What is the cause?
- White matter (axons) injuries diffused over the brain
- Frontal or lateral impact often results in DAI
- Often the result of rotating forces that cause axons to become torn or damaged (because of opposing forces)
↪ often combined with microhaemorrhages and axonal degeneration
Closed head injuries - primary effects
What is affected if there is axonal damage (shearing) in the corpus callosum?
- Damage to the corpus callosum - some axonal extension can be missing
↪ Damage extends far from focal site due to axonal disruption and inflammation - Leads to atrophy and corresponding neuropsychological dysfunction
- Diminished speed of processing due to hemisphere integration issues
Closed head injury - primary effects
Biomechanical features resulting from DAI
- Shearing forces tear delicate vasculature
- Hemosiderin, an iron-laden residue, shows in MRI for subacute and chronic injuries
- Contusions (local bruising) or subdural haematoma concerning due to pressure on the brain surface
Closed head injuries - primary effects
Coup and Contrecoup lesions
Another complication that can happen
- Various mechanical forces resulting from a blow to the head cause TBI
- A coup is damage at the site of impact
- Pressure resulting from a coup (where the injury happens) may push the brain to the opposite end or side of the skull, producing a contrecoup
- Leads to injury in both sides
Closed head injuries
What secondary injuries (effects) can be observed? What can be seen on brain scans?
- Secondary Brain Injury: As damaging as initial injury due to physiological processes
- Factors: Elevated intracranial pressure (ICP), brain swelling (edema - bleeding from some part of the brian), insufficient oxygen (hypoxia), insufficient blood supply (ischemia) - necrosis of brain tissue, fever (pyrexia), and infection
- Brian scans look similar to Demensia patients who have also an increase of the volume of ventricles and the gyri and sulci increase as a sign of cell loss
Closed head injuries
Cognitive and mental impact
- Reduced mental speed, attention (related to slowing of info processing), cognitive efficiency
- Impact on high-level reasoning and executive functions
- Impaired memory (difficulty with remembering recent info, coming up with words, remembering appointments…)
- Complaints of confusion, irritability, distractibility (attention) and fatigue
- Social cognition changes: emotionally flat, not taking others into consideration, unable to adapt to social situations
Closed head injuries
Sensory alterations
- Impaired sense of smell (Anosmia)
- Visual impairments: visual acuity reduced, field defects, double vision, prosopagnosia
- Dizziness and balance problems
- Hearing Defects: tinnitus, hyperacusis
- Sensory hypersensitivity
Types of CHI based on severity
- Mild TBI
- Moderate TBI
- Severe TBI
Closed head injury
The most important association in mild TBI
Complex association between severity and outcome
Is there a specific classification of mild TBI/concussion?
- Controversy over definition and symptom duration
- No universally agreed classification
- Much more agreeablness on moderate and severe TBI’s classification
Mild TBI
Criteria of the American Congress of Rehabilitation Medicine
(ACRM) for mild TBI?
- Any period of loss of consciousness (LOC) lasting for 30 minutes or less
- Any loss of memory for events immediately before or after the accident (Post-Traumatic Amnesia, PTA) not exceeding 24 hours
- Any alteration in mental state at the time of the accident (e.g., feeling dazed, disoriented, confused)
- Focal neurological deficits that may or may not be transient
Mild TBI
Epidemiology
- Over 1.5 million documented TBIs annually; ~80% are mild TBI (extremely common)
- Stats based on hospital records, but an estimated 25% never visit the ER, likely making the real rate higher
- Approximately half of the cases meeting research criteria for mTBI are never formally diagnosed
Mild TBI
Neuropathology
- Mechanical Forces and Cellular Changes: Mechanical forces that alter cellular physiology and anatomy, especially affecting the axons
- Physiological Disruptions: Potentially permanent cellular function changes and acute inflammatory reactions, especially in white matter
Mild TBI
How does mTBI progress and what can it result in?
- Cognitive issues may not manifest until days or weeks aften an accident due to other injuries or medication
- Most individuals recover within hours to weeks, particularly after sports concussions, but a small percentage have long-term issues
- Even with cognitive improvement, symptoms like headaches, fatigue, and dizziness persist in many patients
- Studies suggest that reaction time and neurophysiological measures may reveal subtle, long-term mTBI affects better
Mild TBI
Why is it difficult to predict the outcomes? What can actually help to predict them?
- Interactions between cognitive, emotional, and behavioural factors, that were present before the injury, make predictions challenging
- Inconsistent findings on the role of Loss of Consciousness (LOC) in predicting cognitive outcomes
- Post-Traumatic Amnesia (PTA), life events, and emotional distress can be predictive but lose strength over time
- Age over 40, pre-existing conditions, and history of brain illness are red flags - the best predictors
- Self-reported cognitive issues are more strongly related to emotional state and premorbid traits than actual cognitive
impairments
Mild TBI
Post-concussion syndrome
Definition, causes, cogniform disorder
- Immediate symptoms and persistent symptoms lasting beyond 3 months, not consistent with formal assessments
- Does not mean it’s malingering
- Symptoms may be maintained or worsened by stress or depressive reactions at the time of the accident
- Outcomes affected by a range of neurological, physical, and psychological factors (inadequate coping style, catastrophising)
- Premorbid personality or psychiatric disorders can contribute to the chronicity of postconcussion symptoms
- Cogniform disorder - patients with excessive cognitive complaints and/or unexpectedly poor cognitive performance given their severity of their injury (unconscious)
Mild TBI
Whiplash syndrome
- Common in car accidents
- Typical symptoms include neck pain, occipital headache, back pain, and upper limb pain (but the symptoms are very varied)
- Patients unlikely to meet criteria for concussion or mild TBI, most likely no actual brain injury in majority of cases
- Mixed views on whether neck abnormalities can be objectively demonstrated
- Discrepancies in evaluating the validity of complaints
- Chronic pain is the most common persistent complaint (that’s mostly what distinguishes it from post-concussion syndrome)
- Impact on sleep and cognitive function, mostly attention and memory, dizziness
Mild TBI
Cognitive deficits in mild TBI
- Early Stages Post Mild TBI: Moderate to severe communication, perceptual, or conceptual disturbances
- Symptoms clear up for most but subtle defects may remain
- Attention problems are most common, include poor concentration, distractibility, and mental fatigue
- Sensory and perceptual issues often reported, including visual incoordination, photophobia (not able to deal with bright lights), dizziness, deafness, or tinnitus
Mild TBI
Non-cognitive Impairments
- Headaches are common, even in post-acute stage
- Dysphoria and fatigue are very common
- 35% prevalence of depression
What is moderate TBI and what is its epidemiology?
- Definitions vary in clinical criteria, including GCS scores (GCS score: 9-12 usually)
- Few specific studies on moderate TBIs compared to mild or severe
- 8-10% of all TBIs are moderate; some reviews suggest 7-28%
Moderate TBI
Cognitive deficits
- Ongoing cognitive deficits at six months, especially in information processing speed
- Short-term memory deficits are common
- Frontal and/or temporal bruising often results in behavioural changes (hyperorality, saying inappropriate jokes or vulgar comments…)
- Temporal lobe damage may result in learning disorders or affective changes (lot of ups and downs but even completely flat mood)
Moderate TBI
Progression and Outcome
- Patients generally function independently
- Many return to work but differ from their former selves
- Reduced initiative in non-routine activities (related to frontal lobes deficit)
- Emotional processing impaired, affecting relationships and motivation (lack the drive to engage, lack of insight in how affected they are especially 1 or 2 years after the injury)
What is severe TBI and what is its epidemiology?
- GCS score of 8 or less, loss of consciousness for 30 min or more, PTA for more than 24 h
- Less than 10% of TBI victims are severely injured but present substantial societal costs
Severe TBI
Cognitive deficits
- Executive dysfunction: Impulsivity, lack of self-determination, lack of self-awareness
- Memory deficits: Problems with long-term and short-term memory
- Communication: Problems with word finding, reduced logical coherence and context awareness
Severe TBI
Non-cognitive impairments
- Depression and anxiety are very common in TBI patients, regardless of injury severity (more common later on when they gain more insight)
- Tendency for these conditions to intensify over time
- Often a reaction to physical and cognitive limitations
- Higher rates of mania, paranoia, and schizophrenic-like symptoms
- Increased personality disorders: borderline, avoidant, paranoid, OCD, narcissistic
Severe TBI
Progression: Initial phase
- Most patients show some progress but struggle with the severe impact of Traumatic Brain Injury (TBI)
- Gradual improvement in physical status and cognition
- Severe injuries lead to long-term pervasive deficits
- Improvement in learning and other cognitive functions occurs but seldom reaches normal levels
Severe TBI
Progression: >1 year
- Improvement continues but at a slower pace, relying on new learning and compensatory strategies
- Emotional and psychosocial aspects show minor improvements but largely remain static
Severe TBI
Outcome
- Reduced level of independence in daily activities and employment
- Often persistent physical complaints e.g., headaches, dizziness, fatigue, pain
- Return to previous employment levels is rare
- Emotional and physical burdens placed on families
- Social isolation and caregiver depression are common
What other factors determine outcomes? - Moderators
- Age
- Repeated TBI
- Polytrauma
- Alcohol use
How can age act as a moderator of the outcome of TBI?
- TBI most frequent in under 35s, impacting social and employment outcomes
- Early age TBI needs more intensive education and has poorer vocational outcomes
- Increased odds of adverse outcomes, especially post-65
- Aging brain characteristics contribute to worse outcomes, not just injury severity
- Risk of cognitive decline (e.g. dementia) increases nearly 5 times for each 10 years of age
- Increased rates of depression, psychotic disorders, and dementia in older patients
Moderators
What is repeated TBI? What does it result in?
- Second or more mild concussions have increasingly negative cognitive effects
- A single TBI doubles the risk of future head injury
- Chronic Traumatic Enceohalopathy (CTE)
Chronic Traumatic Encephalopathy
- Confirmed presence in athletes with repeated concussions
- Subconcussive injuries can evolve into significant brain damage over time
How can we demostrated CTE with boxing as an extreme example?
- Even without KO history, boxers experience cognitive and motor symptoms
- 20% of professional boxers develop CTE
- MRI shows cerebral atrophy in boxers
- High frequency of neuropathological abnormalities confirmed
Moderators
Polytrauma
- Head injuries often accompanied by trauma to other body parts
- Impacts severity of neurobehavioral conditions
- Cognitive deficits affect polytrauma outcomes
- Multiple skeletal injuries hinder rehabilitation benefits for head-injured patients
Moderators
Alcohol and Substance Use
- TBI patients with prior alcohol abuse have poorer neuropsychological outcomes
- Alcohol and polysubstance abuse are major contributors to the incidence of TBI
- Fronto-temporo-limbic injury decreases impulse control and judgment, increasing likelihood of further substance abuse
- Alcohol exacerbates severity of head injury, neuropathological changes, and outcomes, even accounting for other variables like vehicle crush and demographics
