Head Injuries Flashcards
Stats
- TBI is 4th leading cuase of death in US, leading cause in people aged 1-44
- 50% of all trauma deaths are secondary to TBI, 35% of these are dt GSW to head
When does neuro injury occur
All neuro damage does not occur at moment of impact (primary injury), often evolves over ensuing minutes, hours, days (secondary brain injury)
Primary vs. secondary head trauma
- Primary injury: irreversible cellular injury dt direct result of injury, only way to avoid is to prevent the event
- Secondary injury: damage to cells that were not initially injured, occurs hours to weeks after primary injury. Goal: prevent hypoxia and ischemia
Critical steps to head trauma
- Early recognition of TBI by public
- Early recognition of TBI by EMS
- Dispatch appropriate EMS
- Early intervention by EMS
- Appropriate hospital by EMS
Prehospital treatment of head trauma
- CAB, O2, IVs, C-spine
- Assess and document pupil size and light reflex
- Document duration of pupillary dilation and fixation
- ID hypotension (SBP <90 mmHG)
- ID hypoxia: O2 sat <90%
- Evidence shows raising bp in hypotensive pts with severe head injury improves outcome
- Goal: get pt to hospital that has the right resources in a reasonable amount of time
Monro-Kellie Doctrine
If have a brain bleed, body can compensate for a while, as mass expands, start to herniate and ICP increases
Cerebral perfusion pressure
- CPP = MAP – ICP
- Normal ICP is 10-15 mmHG or less
- Goal: maintain CPP ≥ 70 mmHG **
- Maintaining adequate CPP is more important than keeping normal ICP value
Cerebral Blood Flow
- Brain uses 20% of O2 consumed and 15% of resting cardiac output
- Remains constant over wide range of arterial pressures, if MAP >150, increased cerebral blood flow, if MAP <20 then CBF ceases
Cerebral imaging
- CT scan: NO contrast is gold standard (assume since have TBI prob have c-spine injury so do CT of neck too)
- Plain films: not used much any more
- MRI: not used in acute situations unless known spinal cord trauma
- US: more of a brain death exam, not for acute analysis
Skull fracture
- linear and simple comminuted
- Explore wound
- Prophylactic abx?
- Occipital = high incidence other injury
- If depressed beyond outer table = NS repair
Skull fracture
- Basilar
- Petrous portion of temporal bone
- Results in dural tear: CSF otorrhea/rhinorrhea, battle sign, raccoon eyes, hemotympanum, vertigo, hearing loss, seventh nerve palsy
- Do start prophylactic abx (Ceftriaxone)
Brain Lesions
- Caused by increasing amts of acceleration-deceleration or torsional forces
- MC type of TBI
Brain lesion
- s/sx
- LOC, AMS, amnesia (retrograde or post traumatic), disorientation, sleepiness, abnl coordination or balance, abnl reaction time, poor concentration and comprehension, opposition or other behavior change, diplopia, incontinence
- On the field: vacant stare, lack of coordination, poor performance, wrong huddle, distracted, inappropriate behavior, slurred speech
Types of brain lesion
- Mild concussion
- Cerebral concussion
- Diffuse axonal injury (DAI)
Mild concussion
- Consciousness is preserved
- Noticeable degree of impaired neuro dysfunction
- Often go unnoticed
- Confusion/disorientation with slight anterograde/retrograde amnesia
Cerebral concussion
- LOC + some amnesia
- Return to full consciousness within 6 hrs of injury
- Usu no sequelae
- Some suffer post-concussion syndrome
Diffuse axonal injury
- Prolonged posttraumatic coma not dt mass lesion or ischemia, persistent vegetative state
- Disruption of axons in white matter and brainstem
- Occurs immediately, is irreversible
- Common after MVC and shaken baby syndrome
- Motor posturing and autonomic dysfunction
- Normal CT initially
- MRI shows multiple, diffuse abnormalities
Tx
- concussion
- Serial neuro evaluations Q2-3 hours
- Avoid sedating medications: narcotics, alcohol, antihistamines
- Yes: ICE, Tylenol, light diet
Post concussive sx
- At 3 months post injury, 20-40% have post concussive syndrome
- Neuropsychiatric impairments: attention, concentration
- Somatic complaints: HA, fatigue, dizzy
- Affect: depression or anxiety
Secondary Impact syndrome
If receive second injury after first injury has healed, lose ability to regulate pressure in brain and can herniate and die
Return to play after concussion
- No sports for 5-7 days
- Should f/u with PCP or neurologist before RTP
- Must be asx for a week before RTP
Impact program for concussions
- Computer test that can be administered by coach, trainer, medical provider to measure baseline and post injury performance.
- Measures attention, memory, processing speed, reaction time
- Measures cognitive function: attention span, working memory, sustained and selective working time, response variability, non-verbal problem solving, reaction time
- Post-concussion testing within 24-72 hours of injury
Focal brain lesions (4)
- epidermal hematoma
- Subdural hematoma
- traumatic SAH
- Contusion
Epidural hematoma
- Blunt trauma to temporoparietal region
- 80% associated with skull fracture
- Usu middle meningeal artery under the temporal bone
- May experience a “lucid interval” and then crump
- Tx: acute craniotomy with sx drainage
Subdural hematoma
• Tearing of veins • Sudden acceleration-deceleration injury • Common in elderly and alcoholics • Acute, sub-acute, chronic - Acute < 2 weeks - Chronic >2 weeks
Traumatic SAH
- MC CT finding in moderate to severe TBI
- HA, photophobia, meningismus
- Early SAH triples mortality
- CT: can see blood inside gyri
Four types of brain herniation
- Uncal transtentorial
- Central transtentorial
- Cerebellotonsillar
- Upward posterior fossa
How to select a hospital for head trauma care
- Trauma center preferred
- Want immediate dx and interventional capabilities and appropriate medical personnel
- CT scan and operating room
- ICP monitoring capabilities
- ICU
Reasons to CT
- LOC or persistent AMS
- Intoxicated
- Other associated injuries
- Poor f/u likely
Reasons to not CT
- Alert and awake and not confused
- Reliable family and transportation
- Knowledge and wits to come back if things get worse
Tools to use to determine extent of head injury
- Canadian CT head injury/trauma rules for adults
- PECARD and Pediatric NEXUS II Head CT Decision for Blunt Trauma for pediatrics
When to admit head trauma
- GCS < 14 or
- Not CT available or abnl CT
- Penetrating in jury
- LOC or fluctuating LOC
- Severe HA
- Intoxicated
- Skull fx
- Sig associated injuries
- No reliable caretaker
- Not able to promptly return to ED
- Sig amnesia
CSF leak
Prognosis for head trauma
- Poorer as GCS decreases
- Inversely proportional to age
- Pupillary findings:
Bilateral worse than single non-reactive pupil (>4 mm is dilated)
Head trauma
- tx
- Aggressive patient resuscitation
- Blood pressure control
- O2
- IV fluids
Goal is euvolemia - Patient positioning: elevate head to dec ICP
- Sedation: brain injuries cause irritation. Also if have shunt
- Mannitol and Lasix – diuretics, can be used together
- NO STEROIDS
- Anticonvulsants: Keppra MC. Phenytoin or carbamazepine may also be used. (Acute control via diazepam or lorazepam)
- Neuromuscular blockade: paralysis
CSF reduction: ICP monitoring device, release CSF based on ICP
IV fluid tx
- Goal is euvolemia
- Isotonic fluids to avoid hyperglycemia
- Non-dextrose containing fluids: dextrose crosses bbb and can cause edema
- Watch for hyponatremia
- Monitor I&Os
- Foley catheter
Treatment for intracranial HTN
No specific tx unless signs of herniation or neuro deterioration
head trauma pearls
- Scan all elderly heads if any possibility of head injury
- Scan all pts on ASA, Coumadin, Plavix if any possibility of head injury
- Repeat neuro exams (inc pupil exams)
- Don’t hesitate to intubate in a controlled setting if at all worried will lose airway