Cerebrovascular diseases

all disorders in which an area of the brain is temporarily or permanently affected by ischemia or bleeding

cerebrovascular disease

a lack of blood flow to a part of the brain causing cell death or infarction and results in acute focal neurological symptoms

stroke or cerebrovascular accident

describe and name the two types of strokes. Which one is most common?

ischemic stroke (most common): blockage of an artery

hemorrhagic stroke: bleeding of a cerebral artery

occlusion of an upstream artery ultimately resulting in infarction

ischemic stroke

with an ischemic stroke, sustained ischemia leads to _____ which leads to _____

sustained ischemia → infarction (cell death) → liquefactive necrosis

ischemic stroke: when do you see eosinophilic cytoplasm and pyknotic nuclei (red neurons)

0.5-1 day

ischemic stroke: when do you see necrosis and neutrophils?

1-3 days

ischemic stroke: when do you see macrophages (microglia)?

3-5 days

ischemic stroke: when do you see reactive gliosis (astrocytes) and vascular proliferation?

1-2 weeks

ischemic stroke: when do you see glial scars?

> 2 weeks

thrombotic stroke seen in older persons, especially those with high cholesterol and atherosclerosis

cerebral atherosclerosis

occlusion at common carotid bifurcation

pt presents with a shade over eye/vision

amaurosis fugax (thrombotic ischemic stroke: atherosclerosis)

with a thrombotic ischemic stroke: atherosclerosis with a site of occlusion at the middle cerebral artery, what does the pt present with?

contralateral arm and face weakness

chronic hypertensive vasculopathy

lenticulostriate artery → _____

“lake-like” appearance on MRI

lipohyalinosis leading to lacunar stroke

occlusion flow due to an thrombus that has moved to another part of the body

embolic ischemic stroke

if you see an “embolic shower” where the affected areas can be seen on imaging to be on both sides of the brain

cardiogenic embolic ischemic stroke (clot came from the heart)

what are the 3 noncardiogenic embolic ischemic strokes?

1. paradoxical embolus

2. fat embolism

3. amniotic fluid embolism

venous thromboembolism (DVT) → patent foramen ovale/ atrial septal defect → carotid circulation

paradoxical embolus (non-cardiogenic embolic ischemic stroke)

fat globule enters systemic circulation after long bone fracture (yellow marrow)

fat embolism (non-cardiogenic embolic ischemic stroke)

amniotic fluid enters the mother’s blood stream during or shortly after birth

this is an obstetric emergency

amniotic fluid embolism (non-cardiogenic embolic ischemic stroke)

border zones/ watershed areas are prone to infarction during global hypoperfusion (low flow state)

global ischemic stroke (cortical watershed areas (ACA, MCA, and PCA) and subcortical watershed areas (MCA and ACA))

with sustained ischemia you can get damage to the blood vessels which can lead to reperfusion which can lead to hemorrhagic conversion of infarct

hemorrhagic transformation

if you have reperfusion leading to hemorrhagic conversion of the infarct and you get: petechial bleeding into infarct without mass effect

hemorrhagic infarction

if you have reperfusion leading to hemorrhagic conversion of the infarct and you get: more severe bleeding with mass effect (potentially life threatening)

parenchymal hemorrhage

How do we clinically manage a patient with ischemic stroke?

if you suspect an ischemic stroke then order a CT and then if <4.5 hours then you start them on tPA

brief, reversible episodes of focal, nonconvulsive ischemic neurologic disturbance

between attacks a neuro exam may appear normal

Transient ischemic attacks (TIAs; mini strokes)

what is associated with cerebral atherosclerosis (amaurosis fugax)

Transient ischemic attacks (TIAs; mini strokes)

due to bleeding into the brain by the rupture of a blood vessel

hemorhhagic stroke

what are the two types of hemorrhagic stroke?

intracerebral hemorrhage and subarachnoid hemorrhage

bleeding into the brain parenchyma

intracerebral hemorrhage

bleeding into the subarachnoid space

subarachnoid hemorrhage

explain the disease process of a hemorrhagic stroke

vessel rupture leads to mass effect and edema (a hematoma forms and expands and compresses on the tissue and elevates ICP)

then you have blood where it’s not supposed to be and it is toxic to the brain

then adjacent vessel constrict and you can have secondary ischemic stroke (so you get both an ischemic and a hemorrhagic stroke)

simplified:

vessel rupture → hematoma → toxic blood → secondary ischemic stroke

cause: hypertension, cerebral amyloid angiopathy, or trauma

presentation: focal neurological deficits depending on location (sudden onset)

imaging: hyperdense area on CT (light colored blob)

location: within the brain parenchyma itself

intracerebral hemorrhage

long standing hypertension → degeneration of tunica media

microaneurysms and you see blood in the basal ganglia

Charcot-Bouchard aneurysms

non-lobar intracranial hemorrhage

accumulation of cerebral amyloid-beta in the tunica media and adventitia

you get vascular fragility

associated with variants of the apolipoprotein E

you see vascular dementia (stepwise cognitive decline)

susceptibility weighted imaging: you see dot hemorrhages

cerebral amyloid angiopathy

lobar intracerebral hemorrhage

cause: trauma or ruptured aneurysms (berry aneurysms)

presentation: “thunderclap” headache or “worst headache of my life”

subarachnoid hemorrhage

what is the most common cause of a subarachnoid hemorrhage

trauma

what is the most common spontaneous subarachnoid hemorrhage?

aneurysmal subarachnoid hemorrhage

where is the most common location for an aneurysmal subarachnoid hemorrhage

ACOM (anterior communicating artery)

starburst pattern on a CT

subarachnoid hemorrhage

what are risk factors for an aneurysmal subarachnoid hemorrhage

Marfan’s or ehlers danlos

female

family history

smoking

ADPCKD

what is it when we see a collection of dysplastic dilated blood vessels

“tangle” of vessels

arteriovenous malformations

explain depressed skull fractures

they can cause compression of bone into the parenchyma of the brain

you see: ecchymosis behind ear (battle’s sign), raccoon eyes, and CSF leakage and meningitis may follow

basilar skull fracture

blow to surface of brain

contusion: bruise caused by blunt trauma

direct parenchymal injury

blow to head may result in contusion at point of contact and/or on brain surface diametrically opposite

coup or contre-coup injury

a mild traumatic brain injury that results in temporary neurological dysfunction due to rapid brain movement

CT is negative

concussion

damage to deep white matter regions

blast injuries

you see petechial hemorrhages

immediate deep coma and high rate of fatality

diffuse axonal injury (DAI)

cause: skull fractures that damage middle meningeal artery

presentation: lucid interval followed by rapid deterioration

imaging: lens shape

epidural hematoma

cause: tearing of bridging veins (often seen in the elderly and chronic alcoholics)

presentation: symptoms develop over hours to weeks

subdural hematoma (you see the crescent shape on imaging)

shaken baby syndrome is associated with what brain injury?

subdural hematoma

cause: extension of intracerebral hemorrhage or trauma commonly seen in preterm infants: germinal matrix hemorrhage

intraventricular hemorrhage

“midline shift”

most common type

can cause headaches due to increase in intracranial pressure and contralateral leg weakness

what is it and what structure?

subfalcine herniation

cingulate gyrus

you see a blown pupil

ipsilateral oculomotor nerve is compressed

needs immediate surgical intervention

what is it and what structure?

transtentorial herniation

uncus

compression of the brainstem and medulla oblongata

disrupts vital functions like respiration and cardiovascular regulation

obtundation (decreased alertness)

what is it and what structure?

transforaminal herniation

cerebellar tonsils