Head Injuries Flashcards
head injuries
- cause of 1.4 million ER visits are for traumatic brain injuries
- 235,000 are hospitalized
- 50,000 are fatal
- TBIs (traumatic brain injuries) make up about half of all trauma victims
- about 50-99% of patients who survive are left with some degree of permanent neurologic disability.
- MVC are the leading cause of TBI’s of those 5-65 years of age
- These injuries can be obvious and also extremely unnoticeable
scalp
- strong flexible mass of skin, facia, muscular tissue
- highly vascular
- hair provides insulation
- SCALP
- Skin
- Connective tissue
- Aponeurotica
- Layer of areolar tissue
- Periosteum of skull
skull
-facial bones
-cranium
0vault for the brain
-strong, light, rigid spherical bone (flat)
-unyielding to increased intracranial pressure (ICP)
-Bones:
-Frontal
-Parietal
-Occipital
-Temporal
anatomy and physiology of the head
- the interior of the cranial vault is not smooth -> not a lot of flexibility for trauma
- This is problematic for any motion of the brain.
- The only opening of the cranial vault is through the bottom called the Foramen magnum.
meninges
- from the interior of the skull the brain is covered by 3 separate membranes
- outer to inner
- epidural space
- dura mater
- subdural space
- arachnoid space
- subarachnoid space
- pia mater
epidural space
-under normal circumstance it does not exist, middle meningeal arteries follow grooves in the temporal bone here
dura mater
- Made of rough fibrous tissue
- Forms Tentorium:
- Internal Support Structure that divides cerebrum and cerebellum
subdural space
- Space that is spanned with Veins
- Low pressure
arachnoid space
Covering over the brains vasculature
subarachnoid space
Gap in which brains vasculature runs
pia mater
Thin covering Directly over the brain.
cerebrum
-Divided into left and right hemispheres
-four lobes:
-Frontal- Contains emotions, motor function, expression of
speech
-Parietal- Contains sensory function and spatial orientation
-Occipital- Contains vision
-Temporal- Reg. memory functions, are of speech
reception & integration
cerebellum
Involved in gross motor function
brainstem
Contains Midbrain, Pons, Medulla
medulla (oblongata)
-Acts as a path way for ascending and descending nerve tracts
-Controls several body functions
-Regulations of heart rate, blood vessel diameter,
breathing, swallowing, vomiting, coughing,
sneezing
pons
-Contains ascending and descending nerve tracts -Relays information from the cerebrum to cerebellum -Houses the sleep center and respiratory center -Like medulla helps in the regulation of breathing
midbrain (mesencephalon)
-Involved in hearing through audio pathways
in the CNS
-Responsible for visual tracking of moving
objects, turning the eyes
-Coordinates regulation of the automatic
functions that require no conscious thought .
cranial nerve
Head Contains 12 cranial nerves that originate from the brain and brain stem.
mean arterial pressure
- ensure circulation to brain tissue
- diastolic pressure + (1/3 pulse pressure) = MAP
- minimal value is 60 mmHg to profuse organs
cerebral perfusion pressure
- amount of pressure that is needed to push blood through the cerebral circulation
- accounts for cerebral pressure
- CPP = MAP - ICP (intracranial pressure)
- normal intracranial pressure = 7-15 mmHG
cerebral blood flow
- most important factor for the brain
- brain retains this flow through autoregulation
traumatic brain injuries
- are categories into 2 categories
- primary- result of direct injury
- secondary- result of on going injury process that is set in motion by the primary injury
cranial injury
- trauma must be extreme to fracture skull
- linear- crack
- depressed- depressed and goes downward into brain
- open- exposed to environment -> infection
- impaled object- passing through the skull
basal skull
- unprotected
- bottom skull
- spaces weaken structure
- relatively easier to fracture
signs of basal skull fracture: battle signs
- retroauricular ecchymosis - bruising behind ear
- associated with fracture of auditory canal and lower of skull
basal skull fracture signs: racoon eyes
- bilateral periorbital ecchymosis
- associated with orbital fractures
basilar skull fracture
- may tear dura
- permit CSF to drain through an external passageway
- may mediate rise of ICP
- evaluate for target or halo sign
- clear part of the CSF will be on the outside ring of a blood drop coming from the ear
brain injury
- as defined by the national head injury foundation
- a traumatic insult to the brain capable of producing physical, intellectual, emotional, social and vocational changes
- classification:
- Primary- caused by forces of trauma
- Secondary- caused by factors resulting from the primary injury
direct brain injury types
- coup- injury at site of impact (usually more severe)
- contrecoup- injury on opposite side from impact -> brain sloshes back
direct brain injury categories: focal
- occur at a specific location in brain
- differentials:
- cerebral contusion
- intracranial hemorrhage
- > epidural hematoma
- > subdural hematoma
- intracerebral hemorrhage
direct brain injury: diffuse
- concussion
- moderate diffuse axonal injury
- severe diffuse axonal injury
cerebral contusion: focal injury
- blunt trauma to local brain tissue
- capillary bleeding into brain tissue
- common with blunt head trauma
- confusion
- neurologic deficit
- personality changes
- vision changes
- speech changes
- result from coup-contrecoup injury
intracranial hemorrhage: epidural hematoma: focal injury
- bleeding between dura mater and skull
- blood is where the brain should be -> herniation
- involves arteries - middle meningeal artery most common
- rapid bleeding and reduction of oxygen to tissues
- patients will have lucid interval
- unconscious goes unconscious again
intracranial hemorrhage: subdural hematoma: focal injury
- bleeding within meninges
- beneath dura mater
- above arachnoid
- slow bleeding- superior sagittal sinus
- signs progress over several days
- slow deterioration of mentation
- blood is displacing the brain
intracranial hemorrhage: intracerebral hemorrhage: focal injury
- ruptured blood vessel within the brain
- presentation similar to to stroke symptoms
- Signs and symptoms worsen over time
intracranial perfusion
- cranial volume is fixed
- 80% = cerebrum, cerebellum, and brainstem
- 12% blood vessels and blood
- 8% CSF
- increase in size of one component diminishes size of another
- inability to adjust = increased ICP
- increase in any one of these things will displace CSF and eventually brain and eventually herniation
compensating for pressure building up
- compress venous blood vessels
- reduction in free CSF
- pushed into spinal cord
- pressure builds
decompensation for pressure
- increase in ICP
- rise in systemic BP to perfuse brain
- further increase in ICP
- dangerous cycle !
role of carbon dioxide
- increase of CO2 in CSF
- cerebral vasodilation
- encourage blood flow
- reduce hypercarbia
- reduce hypoxia
- contribute to increased ICP
- causes classic hyperventilation and hypertension
- reduced levels of CO2 in CSF -> cerebral vasoconstriction -> cerebral anoxia
factors affecting ICP
- vasculature constriction
- cerebral edema- swelling
- systolic blood pressure
- low BP- poor cerebral perfusion
- high BP- increased ICP
- carbon dioxide
- reduced respiratory efficiency
cascade
-cranial insult -> tissue edema -> increased ICP -> compression of arteries -> decrease cerebral blood flow -> decrease O2 with death of brain cells -> edema around necrotic tissue -> increase ICP with compression of brain stem and respiratory center -> CO2 accumulates -> vasodilation -> increase ICP due to increased blood volume -> death
increased pressure
- compresses brain tissue
- herniates brainstem
- compromises blood supply
signs and symptoms of upper brainstem displace (from pressure)
- vomiting
- Altered mental status
- Pupillary dilation
signs and symptoms of medulla oblongata displace (from pressure)
- Respiratory
- Cardiovascular
- Blood pressure disturbances
diffuse brain injury
- Due to stretching forces placed on axons
- Pathology distributed throughout brain
- Types:
- Concussion
- Moderate diffuse axonal injury
- Severe diffuse axonal injury
diffuse brain injury concussion
- Mild to moderate form of diffuse axonal injury (DAI)
- Nerve dysfunction without anatomic damage
- Transient episode of Confusion, disorientation, event amnesia
- Suspect if patient has a momentary loss of consciousness
- Frequent reassessment of mentation
- ABCs
diffuse brain injury moderate diffuse axonal injury
- “Classic Concussion”
- Same mechanism as concussion
- Additional: minute bruising of brain tissue
- Unconsciousness -> confusion
- If cerebral cortex and RAS involved
- May exist with a basilar skull fracture
- Signs and Symptoms
- Unconsciousness or persistent confusion
- Loss of concentration, disorientation
- Retrograde and antegrade amnesia
- Visual and sensory disturbances
- Mood or personality changes
diffuse brain injury severe diffuse axonal injury
- Brainstem Injury
- Significant mechanical disruption of axons
- Cerebral hemispheres and brainstem
- High mortality rate
- Signs and Symptoms:
- Prolonged unconsciousness
- Cushing’s reflex
- Decorticate (flexion) or decerebrate (extension) posturing
altered mental status
- altered orientation
- alteration in personality
- amnesia
cushing’s reflex (triad)
- increased BP
- bradycardia
- erratic respirations
- these 3 symptoms are really only ever seen together for brain injury
vomiting
- without nausea
- projectile
body temperature changes
- changes in pupil reactivity (maybe dilated)
- decorticate posturing
blood glucose
-obtain blood glucose level on all patient with AMS if there is a altered mental state
brain injury: things to look for
- cushings reflex
- body temperature changes
- vomiting
- altered mental status
pathophysiology of changes
- frontal lobe injury- alterations in personality
- occipital lobe injury- visual disturbances
- cortical disruption- reduced mental status or amnesia
- > retrograde- unable to recall events before injury
- > antegrade unable to recall events after trauma -> repetitive questioning
- focal deficits- Hemiplegia, weakness, or seizures
upper brainstem compression
- Increasing blood pressure
- Reflex bradycardia
- Vagus nerve stimulation
- Cheyne-Stokes respirations
- Pupils become small and reactive
- Decorticate posturing
- Neural pathway disruption
middle brainstem compression
- Widening pulse pressure
- Increasing bradycardia
- Central Neurogenic Hyperventilation
- Deep and rapid
- Bilateral pupil sluggishness or inactivity
- Decerebrate posturing
lower brainstem injury
- Pupils dilated and unreactive
- Ataxic respirations
- Erratic with no pattern
- Irregular and erratic pulse rate
- ECG changes
- Hypotension
- Loss of response to painful stimulus
brain injury: eye signs
- Indicate pressure on
- CN-II, CN-III, CN-IV, and CN-VI
- CN-III (Oculomotor nerve)
- Pressure on nerve causes eyes to be sluggish, then dilated, and finally fixed.
- Reduced peripheral blood flow
- Pupil Size and Reactivity
- Reduced pupillary responsiveness
- Depressant drugs or cerebral hypoxia
- Fixed and dilated
- Extreme hypoxia
recognition of herniation
- cushings reflex- increasing blood pressure, decreasing pulse rate, respirations that become erratic
- lower level of consciousness
- GCS < 9 and dropping
- singular or bilaterally dilated and fixed pupils
- Decerebrate or decorticate posturing
- No movement with noxious stimuli
glasgow coma scale
-know this
Trauma to the eye or Orbit
- Eyelid laceration: Laceration to eyelid,
- Cover Both Eyes with lose dressing. Lac of globe is possible.
- Corneal abrasion: Scratch to epithelial covering of the cornea
- Cover both eyes, to limit light and sympathetic movement
- Blow out fracture: Increased pressure due to outside insult causes the base of orbital socket to fracture inward
Trauma to Nasal
-Usually simplistic injury, Be ware of basilar skull injuries
midface injuries
- Le fort 1: Involves a horizontal detachment of the maxilla from the nasal floor
- Le fort 2- Fracture of the right and left maxillae, medial orbital floor and nasal bones.
- Le fort 3- Involves the facial bones being fractured off the skull “Craniofacial disjunction”
head injury management: airway
- Suctioning
- Patient positioning
- OPA and NPA use
- Endotracheal intubation- Orotracheal; RSI
- Cricothyrotomy
- Oxygen
- 15 LPM/NRB
- Begin at 10-12 breaths/min
- adjust breathing rate to maintain ETCO2 at 35–40 mmHg
- Continuous waveform capnogrpahy
head injury management: circulation
- Hemorrhage Control
- Blood pressure maintenance
- Fluid resuscitation to SBP of 90 mmHg
hypovolemia
- Reduces cerebral perfusion and hypoxia.
- Consider early management with 2 large bore IVs and isotonic fluids.
- Prevents slower compensatory mechanism.
- Maintain SBP 90 mmHg in an adult.
- Maintain SBP 80 mmHg in a child.
- Maintain SBP 75 mmHg in a young child.
- Maintain SBP 65 mmHg in an infant.
definitive care: nonsurgical candidates
- Patients with small Hemorrhages Patients with minimal
- Neurological deficits
- Patients who have GCS less that or equal to 4 Unless emergent brain stem release
definitive care: surgical candidates
- Patient with hemorrhages greater than 3cm
- Patients that are neurologically deteriorating
- intracranial Hemorrhage associated with structural lesion
- Improve chance of good outcome
- Young Patients with a moderate lobar hemorrhage with deterioration
