Path- 5: Trauma Flashcards
Where does the blood accumulate in an epidural hematoma?
between the calvaria and the dura
What causes epidural hematomas?
blow to the side of the head
What vessel is ruptured in an epidural hematoma?
MMA
What is the pathogenesis to epidural hematomas?
Aympomatic for first 4-8hrs –> when volume gets to be 30-50mL they have Sx that resemble space occupying lesion –> ICP becomes more than cerebral venous pressure –> ischemia –> cortical impairment
What is the Cushing reflex?
protective response to increase CBF and oxygenation. HR decreases, ionotopy increases, BP increases
When volume increases to 60mL, what happens in the epidural hematoma?
brain is shifted laterally away from the side of hematoma, transtentorial herniation, III compression, dmg to reticular formation
What happens if epidurals are untreated with 4-48 hrs?
necrosis of the brainstem –> irreversible dmg –> death or coma
Why do you pass out when u get it in the head when boxing?
hit the reticular formation
Rupture of what vessels cause subdural hematomas?
bridging veins
Causes of subdural hematomas?
falls, assaults, accidents, kinky role-playing high-velocity activites because your gf’s mom is gone grocery shopping for 10 minutes.
What is the pathogenesis to subdural hematomas?
brain impacts skull –> shearing of veins in subdural space –> bleeding into subdural space –> stops bleeding at 25-50mL due to local tamponade effect
“When life gives you tampons… you make tamponade.”
What is the pathology if subdural hematomas are left untreated?
After several weeks, granulation tissue appears, which creates a membrane above hematoma by using fibroblasts
What are the 3 routes of evolution for static subdural hematomas?
- may be rabsorbed (good!)
- remain static with potential for calcification (eh…)
- hemorrhage may enlarge and re-bleeding within 6 mo. (no bueno)
What are the Sx of subdural hematomas?
headaches, CL weakness, szrs, cognitive dysfxn
What happens in subarachnoid hemorrhageS?
bleeding into the subarachnoid space
What causes subarachnoid hemorrhages?
rupture of pre-existing arterial aneurysm (mainly)
What is a super good procedure to treat aneurysms before they burst into subarachnoid hemorrhages?
coiling
What causes cerebral contusions?
usually AP displacement of the brain (kinda like subdurals), lesions at point of impact (coup injury), or lesion on opposite side of impact (counter coup)
What is the immediate life threat in penetrating wounds to the brain?
Hemorrhage
Describe the characteristics of high velocity penetrating wounds to the head
causes centrifugal blast (cylinder disruption), immediate death (explosive increase in ICP –> cerebellar tonsil herniation), boom
What is a big threat in a healed penetrating wound 6-12 mo after the trauma?
Seizures
What happens in hyperextension injuries?
forehead struck from front and driven posteriorly, tears ALL, cord damaged by posterior bony process
What happens in hyperflexion injuries?
head or shoulders hit from behind –> sharp angulation of the spinal cord
What happens in concussions?
Mild injury, transient and reversible of spinal cord fxn
What happens in contusions?
trauma randes from minor bruise –> hemorrhage
What are myelomalacias?
Spinal cord necrosis and edema caused by contusions
What are hematomyelia?
hematomas within the cord fromc ontusions
What are AVM’s?
arteriovenous malformations, unknown cause
What is the main clinical significance of AVMs?
szrs, intracranial/subarachnoid hemorrhages with stroke-like Sx
Where are AVM’s typically seen?
cerebral Cx
True or false: AVM’s do not grow over time, they stay stagnant and keep out from growing into the white matter.
FALSE
What are cavernous angiomas?
large, irregular, thin-walled vascular channels that contain many open spaces
What are the Sx of cavernous angiomas?
typically asymptomatic but can cause intracranial bleeding, szrs, or focal neuro disturbances
What are telangiectasias?
focal aggregates of small vessels
Sx of telangectasias?
may cause szrs and rarely rupture
What are venous angiomas?
focus of few enlarged veins, distributed randomly in the spinal cord and brain, usually asymptomatic and overlaps with cavernous angiomas
Why do cerebral aneurysms burst?
Increase in vascular pressure and a weakened arterial wall
What are berry aneurysms?
arterial defects during embryogenesis when arteries bifurcate
Where are 90% of sacular aneurysms?
Branch pooints in the carotid system
What happens if Berry aneurysms burst?
life-threatening SAH (subarachnoid hem.)
Where are most Atherosclerotic aneurysms?
in major cerebral arteries (vertebral, basilar, internal carotid)
What is the cause of Atherosclerotic aneurysms?
fibrous replacement of media, destruction of internal elastic membrane
What is the major complication to Atherosclerotic aneurysms?
Thrombosis (typically to MCA). These rarely rupture
What are fusiform aneurysms?
an outpouching of the wall on both sides of the artery and doenst have a stem.
Hypertension causes bleeds into what brain structure?
Basal ganglia
What are Charcot-Bouchard aneurysms?
theyre aneurysms of the brain vasculature which occur in SMALL blood vessels (berry happen in large). often in brainstem, assocaited with chronic HTN.
Where are mycotic aneurysms?
They’re infections of the arterial wall –> septic emboli or cerebral abscesses/meningitis
True or false: traumatic aneurysms are rarely cause dissecting aneurysms
true
Where do > 65% of strokes from HTN occur?
Basal ganglia & thalamus
When lipids and hyaline material are deposited in the arterial walls to cause strokes, what is that called?
lipohyalinosis
What are the clinical features of progressive hemorrhages in strokes?
death within hrs –> days, transtentorial herniation and/or rupture into ventricle with massive hemorrhage –> distention of 4th –> compression of vital centers
Premature infants (22-30 wks) have an increase of which type of hemorrhage soon after birth?
Intraventricular hemorrhage
What are global ischemias?
patterns of injuries that are consistent with the anatomy of the cerebral vascualture.
What are watershed infarcts?
ACA, MCA and PCA have overlapping territories –> not perfused well –> infarcts in these “watershed” areas
What happens in laminar necrosis?
necrosis of the superficial layers of the cerebral Cx, typically focal, happens after temporary cardiuac arrest
What are the 2 types of neurons that are selectively sensitive?
- purkinje cells of the cerebellum
2. pyramidal neurons of the Sommer sector I hippocampus
Why are these 2 types of neurons called selectively sensitive?
cuz theyre very sensitive areas to ischemia induced hypoxia, and can easily develop localized necrosis
Why can atherosclerosis cause regional ischemia and cerebral infarction?
Occlusion ir embolization can be hemorrhagic
How do u treat atheroslerotic emboli so it doesnt cause hemorrhagic infarcts?
Anticoagulants (t-PA!)
Infarcts initiated via thrombosis are show what on cross-section?
bland areas in the area of infarct
Infarct cause the affected tissue to transform into what?
Friable (crumbly) tissue
What causes the friable tissue from infarcts?
macrophages, cysts, liquefactive necrosis
What happens whent he proximal and MCA get occuluded by atheroscleosis and thrombosis? What structure is effed?
internal capsule (CL hemiparesis)
What are TIA’s?
focal cerebreal dysfxn that lsts less than 24 hrs, signifies a risk for infarcts
What are strokes in evolution?
Progression of neurological Sx while pt is under observation, shows the PROPOGATION of a thrombus in the carotid or basilar a.
What are complete strokes?
stable neurological defects resulting from cerebral infarcts
What happens if large extracranial and intracranial arteries are occluded dur to atherosclerosis?
depends on where, but u can imagine the Sx when u knock out the ICA, MCA or ACA. yer effed.
The deficits surrounding an occlusion to the circle of willis depend on what?
collateral circulation
What typically damages parencymal arteries/arterioles?
HTN
What happens in small lacunal infarcts?
occlusion of 1 of the penetrating arteries that provides blood to the deep brain structures gets damaged –> yer effed.
What happens if there are multiple parencymal arterial occlusions?
multiple infarcts, dementia
What causes occlusions in capillary beds?
small emboli like fat or air –> petechiae
Venous sinus thrombosis is potentially lethal for which 4 conditions?
- systemic dehydration
- phlebitis
- obstruction by neoplasm
- sickle cell
