Traumatic Brain Injury Flashcards
What are the most common causes of traumatic brain injury (TBI)?
road traffic collisions (RTCs)
falls <2m
What is the presentation of a traumatic brain injury?
history of a blow to the head
headache
vomiting
decreased consciousness
fixed pupils- due to pressure on interpupillary nerves (abducens nerve CNVI- lateral rectus muscle- no lateral movement of eye)
post traumatic amnesia
seizure
neurological deficit
A glasgow coma scale score of 15 is the best score. Why is this?
this is indicative of a responsive patient
good eye, verbal and motor responses
A glasgow coma scale score of </=8 is indicative of a _________ patient
a comatosed patient
A glasgow coma scale score of 3 is indicative of an _________ patient
unresponsive
What does the Monroe-Kellie doctrine hypothesise/state?
it states that the sum of the volumes of the brain, CSF and intracerebral blood, are constant
this means that when the volume of one component increases, the volume of the other component decreases to keep the sum of the volumes constant
for instant if a mass is present, there are compensatory decreases in the volume blood and CSF
What are the things inside the brain that makes up its volume?
brain tissue
blood
CSF
When compensatory decreases in blood and CSF volumes stops, what happens?
rise in intracranial pressure
What is the consequence of a rise in intracranial pressure?
there is a decrease in cerebral perfusion pressure (CPP)
CPP= MAP - ICP
therefore an increase in ICP leads to a reduction in CPP
this leads less nutrients and oxygen for brain cells and this ischaemia and cell death (infarction)
What are the consequences of an elevated ICP?
midline shift
central descent
uncal herniation —> compression of CNIII (oculomotor)
tonsillar herniation —> cushings response
there is no where for the pressure to go in an enclosed space this, tissue is shifted or pushed downwards leading to brain herniation. Hernias in the brain can compress CNIII
CNIII is located in midbrain
Midbrain also contains breathing and respiratory centres
How are traumatic brain injuries classified ?
acute V chronic
lesion type
diffuse or local
blunt vs penetrating
Severity (glasgow coma scale)
What is the most common type of TBI?
Concussion
Concussions are referred to as _________ TBIs
“mild”
What are the characteristics of a concussion?
brief alteration in neurology (transient)
there is a functional disturbance
no structural injury on CT scan
What is the long term consequence of a concussion referred to as?
post- concussive syndrome
41% of people with concussions will develop post concussive syndrome
What is the management for a concussion?
discharge home with medical device and appropriate adult
graduated return to normal activity
A skull vault fracture is the result of …
a significant force
What are the type of a skull vault fracture?
Linear fracture
Depressed fracture
Open Wound fracture
What is the management of a linear skull fracture?
if no underlying brain injury then no treatment is required
What is the management of depressed skull fracture?
may need elevating if there is an underlying contusion as this increases seizure risk
What is the management of an open skull fracture?
wound closure
-Open fracture breaks through the skin-
Base of the skull fracture is caused by …
high impact injury
Base of skull fractures are usually associated with …
brain injury
What are the clinical presentations of a base of skull fracture?
CSF:
Otorrhoea- CSF drainage from ear
Rhinorrhoea- CSF drainage from nose
Battles sign- bruising over the mastoid process; bleeding and therefore bruising behind the ear
Racoon eyes- fracture bled into the eyes
Deafness
Diplopia
What is the management for a base of skull fracture if the patient is at risk of future meningitis?
pneumovax- pneumococcal vaccine
do not give antibiotics
When should a base of skull fracture be fixed?
if the CSF leak is >2 weeks
What is encephalitis ?
infection of the brain
What is meningitis?
infection of meninges surrounding the brain
List some causes of penetrating TBIs
knife
gun crime
battle TBI- secondary blast, ballistic
Penetrating TBIs have a high rate of infection. True or false
True
How are penetrating TBIs managed?
do not chase all fragments
manage raised ICP
Acute subdural haematomas are common injuries. What are they?
a collection of acute blood (and therefore clot) in the subdural space
subdural space is where the venous sinuses exist
they result from tears in the veins- hence acute collection of blood as blood leaks out into the subdural space
What is the characteristic presentation of an acute subdural haematoma?
cresent shaped haematoma
What kind of injury leads to a subdural haematoma?
de-acceleration injury
often leads to tears in the veins
What is the management for an acute subdural haematoma?
reverse any coagulopathy- dissolve the colt
neuroobeservations
manage intracranial pressure
seizure prophylaxis
+/- surgery
Extradural haemotomas are less common injuries. What are they?
they result from tears in the arteries that exist in the space between the skull and the dura mater (outer protective lining of the brain)
What artery is most implicated in extradural haematomas?
middle meningeal artery
Extradural haematomas have a “talk and die” presentation. Briefly explain what this means
loss of consciousness for the second time; this is because the middle meningeal artery continues to bleed
What is the clinical presentation of extradural haematomas?
biconvex haematoma
What is the management of extradural haematomas?
if they are neurologically stable then close monitoring
if neurologically unstable URGENT SURGICAL EVACUATION
What is the main cause of chronic subdural haemtomas?
innocuous (offensive) bump to the head weeks previously
leads to chronic bleeding from bridging veins
the clot forms and then acts as a sponge for CSF
Why are elderly patients at risk of subdural haematomas?
veins in the subdural space (venous sinus) are very prone to tearing in the elderly
The symptoms for a chronic subdural haematoma presents over days. What are the symptoms ?
hemiplegia- lack of control/stiffness/weakness of one side of the body
headache
confusion
What is the management for a chronic subdural haematoma?
surgical evacuation
reverse anti-coagulants/antiplatelets to stop bleeding
?dexamethasone??
What is a cerebral contusion?
scattered areas of bleeding on the surface of the brain
intraparenchymal bleeding- bleeding in the brain
What are the consequences of cerebral contusions?
may cause generalised swelling
What is the management for a cerebral contusion ?
limited surgical options
What is a diffuse axonal injury?
this is when rotational/twisting forces in the brain cause shearing of axons
when the brain twists and shifts inside the bony skull
shearing of microvessels occurs as well
there is multiple petechial haemorrhage (multiple sites of bleeding)
There is good prognostic factor for diffuse axonal injuries. True or false
False
prognostic factor is poor
What are the management options for diffuse axonal injury?
limited surgical options
What are clinical investigations can be performed for traumatic brain injuries?
CT- includes c-spine
MRI
Coagulation studies
Intra-cranial pressure
What is the aim of the management of TBIs?
to reduce the damage caused by secondary injury
What is a primary brain injury ?
these are the immediate damages caused to the brain by the trauma
What is a secondary brain injury?
ischaemic insult from hypotension, hypoxia, disrupted autoregulation, raised intracranial pressure
What are the management techniques employed for TBIs ?
prevention- education surrounding alcohol, driving
Prehospital- advanced trauma life support protocol ABCDE
Acute- Advanced trauma life support protocol ABCDE
Neuro ITU
Surgical
Rehab
Diuretics- reduce fluid and therefore reduce ICP
List neuro-protective measures that are employed in TBIs
remove hard collar
sit to 45 degree angle
protect airway
avoid hypoxia
avoid hypotension
mannitol to reduce ICP
induced coma
normothermic
AED (automated external defib) - prophylaxis
What are the surgical management techniques for TBIs
CSF diversion
craniotomy- hole in skull
craniectomy
burr-hole- extradural haematoma, acute subdural haematoma
elevation of depressed skull fracture
What are poor prognostic factors of TBIs ?
loss of grey white differentiation
bilateral F&D pupils (full and dilated???)
diffuse injury (not localised)
poly trauma- extracranial injury
brainstem involvement
What are some complications of TBIs?
infection- intra/extracranial
spectrum of disability
affective disorders
psycho-social impairment
pituitary dysfunction
vitamin D deficiency
post traumatic seizures
post- concussive syndrome (long term)
What are the dental considerations for TBIs?
Loose teeth
polypharmacy
poor dental hygiene
concurrent maxillofacial trauma
may be primary presentation of brain injury
What are the stages of a seizure
Prodromal
Aura (early ictal)
Ictal /ictus
Post ictal period
What occurs in the prodromal stage of a seizure?
mood or behavioural change preceeding attack
(hours)
What does the the early ictal/aura stage of a seizure refer to?
these are the symptoms immediately before the attack
localises to point of origin
What is the ictal stage of a seizure?
refers to where the seizure is occuring
the seizure itself
What does the post-ictal stage of a seizure refer to ?
the time immediately after ictus
pt is often confused and irritated
What is the pathogenesis of epilepsy ?
balance between excitatory and inhibitory neurotransmitters is disturbed
decreased GABA action
increased glutamate action
What are the main classifications of epilepsy?
Partial seizures (restricted to one part of the cortex)
Generalised seizures (all over the brain)
Unclassified
Partial seizures can be classified according to their severity. What are the classes of partial seizures according to their severity
simple partial
complex partial
secondar generalised
Partial seizures can be classified according to their site of onset. List the sites of onset for a partial seizure
frontal lobe
parietal lobe
temporal lobe
occipital lobe
What are the types of generalised seizures/epilepsy?
tonic clonic
absence
myoclonic
tonic
What are the characteristics of a simple partial seizure?
- consciousness preserved
- they are of cortical origin
What are the characteristics of complex partial seizures?
- degree of impaired consciousness level- wider effects
- cortical origin
What is a partial seizure?
in a partial seizure only one part of the brain is affected; one area of the cortex, one lobe or one hemisphere
What are the characteristics of a frontal lobe partial seizure?
- jacksonian march- involuntary muscl movement from one group of muscle to the next, usually begins in the hands and face
- todds paralysis- post ictal weakness in the limb affected
- adversive seizures- movement of the head and eyes away from the site of origin
- supplementary motor area- stereotyped movements in sleep e.g.cycling
remember frontal lobe: face, arms, limbs and trunk; watch videos in lect
What are the characteristics of a parietal lobe partial seizure?
sensory cortex origin
parasthesiai in extremity or face
What are the characteristics of a temporal lobe partial seizure?
- complex aura- taste, smell, lip smacking, memory disturbance, semi-purposeful movements, affective disturbance
- automatism involuntary, complicated movement
- associated with hippocampal sclerosis (learning and memory)
What is a generalised seizure?
there is widespread electrical discharge/ disturbance
might be left/right hemispheres or both
What can the initial symptoms of a generalised seizure identify?
Why is this ?
the origin of the seizure
only the origin can be identified by the initial symptoms because the seizure (electrical disturbance) will spread to sub-cortical regions and release discharge before spreading bact to the cortex of both hemispheres (at this time a more diverse range of symptoms can be produced)
What are the characteristics of the tonic phase of a tonic clonic attack?
sudden stiffness of joints and muscles in muscles of arms, legs and trunk
* lasts for 10 seconds
* LOC
* eyes open
* elbows flexed
* legs extended
* teeth clenched
* breath held
What are the characteristics of the clonic phase of a tonic clonic attack?
repeated jerking movements of the arms and legs on both sides of the body
* lasts minutes
* tremor gives way to violent shaing
* eyes roll back
* tachycardia
* tongue biting
What are the post ictal symptoms of a tonic clonic attack?
confusion
headache
Absence seizures are also known as …
Petit mal seizures
List the characteristics of absence seizures
- more common in children
- vacant staring
- may occur multiple times a day
- 5-15 seconds
What are the characteristics of myoclonic seizures?
- sudden brief generalised muscle contractions; of a muscle or group of muscles
- commoner in the morning
- onset after puberty
- degenerative and metabolic disease
- do not last more than a second or two
What does status epilepticus refer to?
a seizure that does not stop after 5 minutes
consciousness does not return between attacks
What are some consequences of status epilepticus?
pyrexia
coma
circulatory collapse
What are some clinical investigations used for diagnosis of epilepsy?
CT
MRI
Electrocencephalogram (EEG)
video telemtry
ECG
serum glucose
What is the management of acute phase epilepsy?
ABCDE
Once seizure is over put in recovery position
do not put anything in their mouth
What are the long term management strategies for epilepsy?
Medical
Surgical
List the dental considerations for patients with epilepsy
- carry out treatment when seizures are infrequent when possible
- keep as much apparatus away from area as possible
- some medicines precipitate condition- be aware of those
- conscious sedation is generally safe (midazolam)
- acrylic best for prostheses
- seizures can result in cranio-facial trauma
- tongue lacerations
