S21C254 - Head Trauma in Adults and Children

Question 1

TBI

Answer 1

• impairment in brain fxn as a result of mechanical force
• can be direct injury from contusion, hematomas, diffuse axonal injury, tearing, shearing
• or secondary injury from a cascade of events following the primary injury - production of free radicals, mitochondrial damage (different from secondary insults)

-mild TBI is neurologic dysfxn without gross lesions or evidence on imaging, may be more metabolic than structural insult, GCS 14/15, brain is very vulnerable during this time, microscopic changes

Question 2

Brain physiology

Answer 2

• consumes 20% of body’s oxygen requirement and 15% of CO
• vasoconstriction occurs with HTN, hypocarbia and alkalosis
• autoregulation of blood flow is disrupted in TBI so hypoxia occurs

Question 3

CPP

Answer 3

CPP = MAP - ICP

MAP = diastolic pressure + (SBP-DBP)/3

elevated ICP reduces CPP and blood flow

Question 4

ICP

Answer 4

-normal ICP is

Question 5

Cushing reflex

Answer 5

• raised ICP
• HTN, bradycardia, respiratory, irregularity
• seen in 1/3 of cases with elevated ICP

Question 6

Goals of care for moderate/severe TBI

Answer 6

• prevent secondary brain injury or insults (HoTN, hypoxia, anemia, hyperglycemia, hyperthermia)
• treat mass lesions
• identify other life-threatening injuries

-HoTN (SBP

Question 7

RSI for TBI:

Answer 7

-etomidate 0.3mg/kg IV
rapid onset (45sec), short duration (3-5min)
may reduce ICP
SE: adrenal suppression with infusions
-ketamine 2mg/kg IV

• succinyl choline 1mg/kg IV (to 1.5mg/kg)
• rocuronium 1mg/kg IV

Question 8

Canadian CT Head Rule (GCS 13-15)

Answer 8

• GCS 30min
• dangerous mechanism (fall >3 ft or ped struck)
• age >65yo

100% sensitive for detecting those who will need neurosurgical intervention (37% specific)
83% sensitive for identifying those pts who will have an intracranial lesion (38% specific)

Question 9

MIld TBI: indictions for CT scan

Answer 9

• GCS 2
• moderate/severe h/a
• age >65
• signs of basilar skull #
• coagulopathy
• dangerous mechanism

Mild TBI with LOC or amnesia, CT if one or more present:

• intoxication
• trauma above clavicles
• persistent amnesia
• post-traumatic seizure

Question 10

Elevated ICP: treatment

Answer 10

• raise head of bed to 30 degrees
• maintain PaCO2 at 35-40mmHg
• maintain O2 sat at >95%
• serial GCS
• mannitol works w/in 30mins and lasts 6-8h, use if pt not hypotensive, bolus 0.25-1mg/kg
• hyperventilation, can do a brief course if impending herniation (cushing reflex), aim for PaCO2 of 30-35mmHG

Question 11

Open Skull #

Answer 11

• administer vancomycin 1g IV plus CTX 2g IV
• give tetanus
• consult neurosurgery
• pneumocephalus - also tx with Abx

Question 12

Basilar skull # and CSF leaks

Answer 12

• basilar skull # is a significant risk factor for intracranial injury
• often involves the petrous part of the temporal bone, the external auditory canal and the tympanic membrane
• assoc with a torn dura that leads to otorrhea/rhinorrhea
• signs and symptoms: otorrhea/rinorrhea, mastoid ecchymosis (battle), periorbital ecchymoses (raccoon), hemotympanum, vertigo, decr hearing, 7th nerve palsy
• battle/raccoon sign take hours to develop
• send otorrhea/rhinorrhea for beta-transferrin study
• CSF leak increases risk of meningitis (tx prophylactically with CTX and vanco)

Question 13

Brain herniation

Answer 13

• uncal transtentorial: expanding lesion temporal lobe or lateral middle fossa, comprsses 3rd nerve parasympathetic fibers causing ipsilateral fixed and dilated pupil due to unopposed sympathetic tone
• central transtentorial: midline lesions frontal. vertex or occipital lobes, b/l pinpoint pupils, b/l babinski signs, increased muscle tone followed by fixed midpoint pupils and decorticate posturing
• cerebellotonsillar: cerebellar tonsils herniate through foramen magnum, pinipoint pupils, flaccid paralysis, sudden death
• upward posterior fossa: posterior fossa lesion causes an upward transtentorial herniation, conjugate downward gaze, absence of vertical eye movements, pinpoint pupils

Question 14

SAH

Answer 14

• traumatic SAH results from disruption of parenchyma and subarachnoid vessels and presents with blood in the CSF
• h/a, photophobia, meningeal signs
• high mortality
• early CT may miss it, CT at 6-8h is better

Question 15

Epidural Hematoma

Answer 15

• blood b/w skull and dura mater
• middle meningeal artery disruption is usual cause
• classic history: blunt head trauma, LOC or altered sensorium, then a lucid period then rpaid neurologic demise (occurs in minority of cases)
• strikes to temporal or lateral head have higher risk
• can cause herniation hours after injury d/t compression
• injury to brain parenchyma often absent

Question 16

Subdural Hematoma

Answer 16

• sudden accel-decel injury and tearing of bridging veins
• hematoma b/w dura mater and arachnoid
• accumulates more slowly
• brains with atrophy are at higher risk (elderly, and children 2w , dark on CT

Question 17

DAI: diffuse axonal injury

Answer 17

• caused by sudden deceleration (MVC, shaken baby)
• usually irreversible and devastating
• punctuate hamorrhagic injury along grey-white jxn

Question 18

GSW to head

Answer 18

• creates a cavity of injury 4x the diamter of the bullet
• GCS >8 have a 25% mortality
• GCS

Question 19

Mild TBI

Answer 19

• diagnosis: any alteration in the mental state at the time or subequent to the event
• Sx: difficulties with memory/attention/executive fxn, depression

Question 20

Concussion:

Answer 20

• 80% recover by 6w
• RTP
• those with Sx >3w should seek further care

Question 21

Pediatric head trauma: signs

Answer 21

• focal cranial nerve deficit, pupillary or facial asymmetry
• decreased sucking reflex
• global decreased level of response
• infants: bulging anterior fontanelle, decr arousal, lethargy, sz, apnea, bradycardia, emesis

-subdural hematoma in infancy is STRONGLY correlated with abuse, may be associated with long-bone or posterior rib # and retinal hemorrhages (10% will be from accidental trauma/MVC)