Head Injury Flashcards
Head injury
Injury to scalp skull or brain
Traumatic brain injury
Non degenerative non congenital insult to the brain from an external mechanical force, possibly leading to permanent/temporary impairment of cognitive, physical, and psychosocial functions, w an associated diminished/altered state of consciousness
Traumatic brain injury mechanisms
Penetrating injury
Closed head injury
Blast injury
What are coup and contrecoup injuries
Coup - brain hits skull side of impact
Contrecoup - brain hits skull opposite to impact
Effects of closed head injuries
Skull fracture
Contusion
Haematoma
Laceration
Diffuse axonal injury
Primary measure for TBI severity
Glasgow coma scale
What GCS scores are mild, moderate, and severe
Mild 14-15
Mod 9-13
Severe <8
What 3 factors are measured in the GCS and what are they measured out of
Eye opening /4
Verbal response /5
Best motor response /6
What does the loss of consciousness scale measure
Time pt unconscious
What does the post traumatic amnesia scale measure
Interval from injury until pt is orientated and can form and recall new memories
TBI diagnostic imaging
CT
MRI
Signs of basal skull fracture
Battle sign
Ottorhea
Raccoon eyes
Hemotympanum
What component in the head acts as a shock absorber
CSF
Pathophysiologies of TBI
Direct Neural tissue injury
Incr ICP
Herniation
Haematoma
EDH
SDH
Traumatic SAH
ICH
Seizures
Why is MRI not used for gunshot wounds
Metal fragments
What creates ICP
Cerebral blood flow + CSF
What is used to measure ICP in unconscious patients
ICP bolt
What can increased ICP lead to
Herniation
Decreased CSF and blood flow to brain -> ischaemia
Normal supine adult ICP
5-15 mmHg
At what ICP can herniation occur
20+ mmHg
Herniation
Abnormal protrusion of brain tissue through folds and openings in the brain
6 types of brain herniation
Uncal
central (transtentorial)
Cingulate (subfalcine)
Transcalvarial
Upward cerebellar (transtentorial)
Downward cerebellar (tonsillar)
Brain herniation symptoms
Dilated pupil
Headache
Drowsiness
High BP
loss of consciousness
Loss of reflex
Seizures
Decorticate/decerebrate posturing
What causes decorticate posturing
Damage to cerebral cortex and/or internal capsule
What causes decerebrate posturing
Damage to midbrain, brainstem, and/or pons
Difference between decorticate and decerebrate posturing
DeCORticate - arms adducted, flexed, at CORE
DEcErEbratE - arms adducted Extended pronated
Types of brain haematoma
Epidural haematoma
Subdural haematoma
Subarachnoid haematoma
Intracerebral haematoma
Epidural haematoma
Blood clot between skull and outer dura
Damage to which artery is the most common cause of EDH
Middle meningeal artery
EDH shape on CT
Lemon
Subdural haematoma
Haematoma in subdural space between dura and arachnoid
Subdural haematomas are usually caused by damage to which vessels
Bridging cortical veins
How does SDH appear on CT
Banana shape
How quickly must a SDH be evacuated
Within 4 hrs
Subarachnoid haematoma
Haematoma in subarachnoid space between pia and arachnoid mater
How does SAH appear on CT
White in sulci or cisterns
Why do traumatic SAH have better prognosis than aneurysmal SAH
More areas affected in aneurysmal
Aneurysm in circle of Willis
What injuries often cause SAH
Skull fracture
Cerebral contusion
Intracerebral haematoma
Blood clot in brain parenchyma
Age range for EDH, SDH, and SAH
EDH - young adults
SDH - all age groups
SAH - older middle age
Seizure
Abnormal sudden electrical disturbance in brain
Clinical signs of seizure
Strange movements
Unresponsive
Staring
Sudden tiredness or dizziness
Not able to communicate or understand others
Early post traumatic seizures vs late post traumatic seizures
Early - within 1 wk of TBI
Late - >1wk after TBI
GCS, LOC, and PTA in mild TBI
GCS 13-15
LOC <30 mins
PTA <1 day
Acute management of mild TBI
GCS 15 - minor clinic + discharge
GCSE 13/4 -> CT - normal discharge, abnormal observe 24hrs+
GCS LOC and PTA in moderate TBI
GCS 9-12
LOC 30min-24 hrs
PTA 1-7 days
Moderate TBI acute management
Transfer to neurological unit for observation
Surgical evaluation of haematoma
Transfer to ICU to allow brain bruising and swelling to reduce
Severe TBI GCS LOC and PTA
GCS 3-8
LOC 24+hrs
PTA 7+days
Severe TBI acute management
Stabilise ABC
Seizure prophylaxis - phypenytoin/levetiracetam
Sedate/induce coma - propofol/benzodiazepines
Rapid reversal of warfarin if taking - fresh frozen plasma + vit K
Why are severe TBI patients put into an induced coma
Prevent secondary brain injury by
Decr ICP
terminate seizures
Facilitate + optimise ventilation
Decr cerebral metabolic rate
Raised ICP acute management
Hyperosmolar therapy - short term
Extraventricular drainage
Decompressive craniectomy
How does Hyperosmolar therapy reduce ICP
Use osmotic gradient to shift water into blood vessels across BBB
Which drugs are used for Hyperosmolar therapy
20% mannitol or 3-5% hypertonic saline
Methods of extraventricular drainage (long term TBI management)
Extraventricular drain
External ventricular drain
Ventriculostomy
How does a decompressive craniectomy help raised ICP and when is it used
Provide space for brain to swell
Used when ICP incr is uncontrollable
Decompressive craniectomy complications
Bleeding
Infection
Seizures
Further brain damage
Tranexamic acid
Antifibrinolytic drug
Pre hospital intervention, must be within 3 hrs of injury
Can TBI be treated
No, only managed
How long until most clinical signs of TBI appear (eg raccoon eyes, battle sign)
~24 hrs
