Neurological: TBI, SCI, seizures Flashcards
(31 cards)
TBI: mechanism of injury, acceleration vs. deceleration
acceleration- occurs when a moving blunt object strikes the head (ex. hit in head with bat) site of impact with skull causes brain injury
deceleration- occurs when person head strikes an immovable object like dashboard and brain moves until it hits skull, rapid deceleration causes brain injury as it hits bony wall of cranium
TBI: mechanism of injury, coup vs. contrecoup
coup- injury affects cerebral tissue directly under the point of impact (acceleration)
contrecoup- injury occurs in a line directly opposite of point of impact (deceleration)
TBI: mechanism of injury, rotational
occurs when force impacting head transfers energy to brain in a nonlinear fashoin so head rotates on neck resulting in shear fores being exherted
ex. boxing (punch side of head)
TBI: mechanism of injury, penetrating injury
a foreign object invades brain
ex. knife
may pass completely through brain and exit opposite side or just bounce around cranium causing multiple injuries in brain
primary brain injury
occurs from direct injury caused by force of impact from traumatic event = immediate damage of neurons
secondary brain injury
occurs in response to primary injury that arises from tissue and system responses to primary injury
involves ischemia, neuronal death, inflammation, cerebral swelling
can lead to worsening outcomes
skull fractures : types
linear- minor injury, not seen to naked eye, need CT scan, can heal without intervention, not life threatining
depressed- force depresses skull inward usually causing fragments tearing through brain tissue, surgical repair and evacuate hematomas beneath fracture
open- where scalp has been lacerated, can expose brain to environment = r/f infection, surgical repair + debridement of contamination, antibiotics
basilar- develops at base of skull with high force, results in rhinorrhea (CFS draining from nose), or otorhea (CFS draining from ear), bruising around eyes, facial nerve paralysis, mastoid bruising. test drainage for glucose (will test positive if CSF), and check for halo sign(ring will form around drop of CSF indicating tear in meninges). drain CSF then dura closes itself
what conditions can cause increased ICP
increase in brain volume (cerebral edema, space occupying lesions like hematoma)
increase in cerebral blood volume (hypercapnia, hypoxia)
increase in CSF
what can happen when there are severe increase in ICP
it impairs cerebral perfusion and oxygenation to brain cells and may cause intracranial hypertension which is life threatening
what are 2 processes that lead to increase in brain volume
1) space occupying lesions- develop as result to tumors, abscesses, hemorhages, hematomas (aka lesions that increase in size)
2) cerebral edema- due to abnormal accumulation of fluid in brains extraceullar space which increases brain tissue volume. can occur after any intracranial insult (trauma, surgery, cerebral anoxia, ishchemia) it doesn’t impair brain function until it results in increased ICP
what are three circumstances that increase serebral blood volume?
hypoxemia or hypercapnia - results in cerebral vasodiilation and increased cerebral blood volume. any systemic process that effects blood levels of oxygen/CO2 directly affects cerebral blood flow, perfusion pressure and blood volume
cerebral venous outflow obstruction- increases with any process that impedes cerebral venous outflow, ex. impeding jugular venous drainage from head (neck/head flexion/rotation, devices too tight like trach ties) also things that increase intrathoacic or intraabdominal pressure (valsava maneuver, use of posititve pressure vent)
loss of cerebral autoregulation- becomes ineffective in prolonged ischemic conditions, sustained increases of ICP and/or states of hyperemia. when autoregulation lost, blood vessels dilate and insult homeostasis by increasing CBV and ICP
what is autoregulation
process where cerebral vessels have capacity to dilate or constrict in response to changes in perfusion pressures
it maintains adeqaute cerebral blood flow by altering cerebral vascular tone
As CPP increases, compensatory vasoconstriction occurs
as CPP decreases, cerebral vasodilation occurs
Requires: CPP within 50-150mmHg + MAP within 60-130mmHg , if this lost, autoregulation is lost
CSF: cause of increase
when CSF increases its circulation or flow is blocked, or its absorption decreases causing a increase in CSF amount
obstruction to CFS outflow can be due to mass lesions or infections
decreased absorption can result from subarachnoid hemorrhage or meninigitits
loss of autoregulation
hypercapnia, hypoxemia
what is hydrocephalus
condition involving increased volume of CSF particularly in ventricles of brain
this can increase ICP
what is a focal brain injury
localized to the area of direct injury
include: contusion to a hematoma
may be result from a concentrated collection of blood from a blunt trauma or intracerebral bleed, or an object
Focal brain injury: subdural hematoma
accumulation of blood between dura and arachnoid layers of meninges
developes secondary to venous injury from tears in the bridging veins
S+S onset = slower
may occur as result of mild brain trauma (elderly/alcoholics), or spontaneously
three catagories:
1) acute (S+S onset <48hrs after injury, drowsy or comatose following injury, headache, confusion, agitated, slow thinking)
2) subacute (develop 48hr-2weeks after injury, headache, mild contralateral hemiparesis, drowsy, confusion occur onset for days or weeks)
3) chronic (S+S onset over weeks after injury, S+S vague, lethargy, vomiting)
Manage: surgical removal of hematoma if shift of brain present on CT or symptomatic + 1cm in size, use burr holes or craniotomy or subdural drain
Focal brain injury- epidural hematoma
occurs in space between dura mater and skull
high impact to temporal areas induce these
S+S: brief loss of consciouness right after injury followed by episode of lucidity then recurrent loss of consciousness, fixed and dilated pupil on same side as impact
manage: cauterizing vessel to evacuate hematoma and placing ICP monitor, osmotic diuretic (to decrease ICP), mechanical ventilation
Focal brain injury- intraparenchymal hematoma
accumulation of blood between parenchyma or tissue of brain rather than between meningeal layers
results from: uncontrolled HTN, ruptured aneurysms, trauma
vary according to location: headache, ALOC, ipsilateral pupil dilation, contralateral hemiplegia
manage: treat increased ICP and optimize CPP, cannot do surgery bc hematoma ais deep within brain
Focal brain injury- contusion
bruising of cerebral soft tissue
commonly seen in traumatic brain injury
cause macroscopic tissue and vessel damage- detectable via CT/MRI
associated with longer periods of unconsciousness
what is diffuse brain injuries
injury occurs in several areas of brain
include concussion and diffuse axonal injury, and subarachnoid hemorrhage
what is concussion
mild traumatic brain injury caused by blunt trauma to head
cerebral damage occurs at microscopic level, not detectable through radiographic or other tests
includes: immediate period of unconsciousness (lasting up to 20 min) and short term amnesia
if mild- will not lose consciousness but appear confused, dazed, stunned
Reports: loss of consciousness, post traumatic amnesia, altered mental status, focal neuro deficits, deterioration
CT ordered
Post concussion syndrome- where concussion symptoms persist for 3 months or more after injury
what is diffuse axonal injury
occurs when shearing forces disrupt structure of neurons and vessels
may be present without bleeding (hard to see on CT/MRI)
results from high speed acceleration/deceleration or rotational injury
present- multiple small hemorrhages
mild DAI- result in comatose state for hours to days followed by recovery with minimal residual neuro damage
severe DAI- high morbidity/mortality
what is subarachnoid hemorrhage
accumulation of blood between meningeal arachnoid and pia mater layer
results in blood leaking into CSF
bleeding can be focal “+ minor or massive and diffuse with intracranial HTN
results from - ruptured aneursysm, uncontrolled HTN, TBI
S+S: acute onset of severe headache (worst headache ever) accompanies with ALOC, diplopia, seizures, photophobia
assessment with TBI
Initial: ABC, vitals then neuro, body for signs of injury
second: hx, meds, allergies, surgeries, comorbid conditions
general systems assessments with interventions to ensure adequate ventilation/oxygen/perfusion
priorities = ABC, neuro assessments to detect deterioration
