Lecture 14: Traumatic Brain Injury

most TBI are due to

falls

second most TBI are due to

motor vehicle accidents (MVA)

GCS stands for

Glasgow Coma Scale

what is GCS

rating scale assessing how awake/alert patients are

ways that the GCS measures what is measures

are their eyes open; response to pain; ability to follow commands

higher GCS score =

more severe TBI

PTA

post-traumatic amnesia

what does PTA measures

inability to create new memories after TBI (anterograde amnesia)

problem with TBI classification methods (GCS, PTA, etc)

people will milder TBI score well on them, so their injuries go unnoticed

MRS stands for

magnetic resonance spectography

how does MRS work

looks at magnetic properties of brain chemicals (not brain tissues) which react/change post-TBI

glutamate post-TBI

increased

MRS goal

gauge severity of injury and NP functioning

choline post-TBI

increased

creatine post-TBI

decreased

N-acetyl aspartate post-TBI

decreased

choline function

memory, membrane synthesis (repairing a damaged membrane)

creatine function

neural protection

SWI stands for

susceptibility weighted imaging

what is SWI’s function

tweaked MRI to see blood (not just tissues)

what does DTI stand for

diffusion tensor imaging

how does DTI work

gauges severity of white matter damage by measuring movement of water molecules

closed head injuries

injuries that do not penetrate the skull

acceleration and deceleration can cause

contusions

contusion

bruise

coup injury

impact injury at the site of impact

contrecoup injury

injury opposite the impact

focal injury

contusions along frontal and temporal poles

sphenoid wings

sharp bones that hold the brain in place

what happens with sphenoid wings during TBI

can damage brain if it is jiggled

what parts of the brain are susceptible to damage from sphenoid wings

inferior frontal lobe, anterior temporal lobe

why does diffuse axonal injury occur

because the brain does not move as one piece

what is diffuse axonal injury (DAI)

axons stretch, causing neuron degeneration

most vulnerable parts of the brain in DAI

brainstem, deep white matter

what happens if you get DAI in the deep brainstem

coma

retrograde degeneration

axon is damaged close enough to the cell body, so the signal cannot be sent back to the cell body, causing cell death

anterograde degeneration

axon is damaged close to the cell body, so the signal cannot be sent to the next neuron

penetrating injuries

direct damage from foreign objects lodged in the brain

risks that come with penetrating injuries

infection, bleeding

why is infection possible with penetrating injuries

since the blood-brain barrier has been broken, any bacteria (from blood, air, shrapnel, etc) can cause infection

why is bleeding possible with penetrating injuries

arteries, veins, and capillaries are damaged

all complications of TBI

• edema

  • intracranial pressure

• herniation

  • intracranial pressure

  • hematoma

• hemorrhage

• skull fractures

• seizures

edema

brain swelling, leading to intracranial pressure

herniation

brain tissue is pushed where it doesn’t belong (disformed) because of brain swelling

hematoma

blood pools in the brain

hemorrhage

bleeding in the brain

how to measure intracranial pressure

spinal tap

subdural hematoma

blood pools in between dura and arachnoid layers

epidural hematoma

blood pools between skull and dura layer

depressed skull fracture

bone fragment is pushed into the brain

PTE stands for

post traumatic epilepsy

T/F: PTE will always cause permanent epilepsy

false

which type of injury (closed head, diffuse, penetrating) is PTE most common with

penetrating

diagnostic criteria (any one) for mild TBI (mTBI)

1. any loss of consciousness

2. any loss of memory before/after event

3. any alteration of mental status

4. focal neurological deficits (abnormal pupil dilation, etc)

symptoms of mTBI

• headache

• dizziness/imbalance

• dizziness/vomiting

• blurred vision

• dilated pupils

• concentration problems

• slowed thinking

• irritability

• sleep disturbance

• retrograde/anterograde amnesia

T/F: effects of mTBI symptoms are cumulative (add up over time w/ more TBIs)

true

cognitive reserve

if we lose a few brain cells too many times, it will cause real effects

how long does it typically take for majority to recover from mTBI

90 days

concussion falls under what severity of TBI

mild

more severe injury =

more severe deficits

which domain has the most deficits with TBI

executive functioning

which domain has the least deficits with TBI

language (aphasia is rare)

frontal lobe syndrome

irritability, impulsivity, social norms violations, impaired self-awareness

frontal lobe syndrome happens bc of damage to (circuit)

orbitofrontal

what is postconcussion syndrome

symptom cluster complication recovery from mTBI

postconcussion syndrome symptoms

in addition to cognitive and personality changes AND last more than 90 days:

• dizziness

• headaches

• photophobia

• sonophobia

• toxic sensitivities

photophobia

sensitivity to light

sonophobia

sensitivity to sound

toxic sensitivities

sensitivity to taste, smell