Cerebrovascular Accident/Transient Ischemic Attack

Cerebral Blood Flow (CBF)

the blood volume that flows per unit mass per unit time in brain tissue

Cerebral Perfusion Pressure (CPP)

difference between mean arterial pressure (MAP) and intracranial pressure (ICP)

provides driving force for circulation across capillary beds of the brain

Cerebral Blood Volume

volume of blood in a given amount of brain tissue

intracranial pressure (ICP)

pressure within the craniospinal compartment

closed system that comprises a fixed volume of neural tissue/blood/cerebrospinal fluid (CSF)

Causes of Increased Intracranial Pressure (ICP)

brain volume increased: brain lesions
diffuse brain pathology
decreased venous outflow
increased arterial blood flow

cerebrospinal fluid blood volume: obstructed CSF circulation
increased CSF production (rare)
blockage in ventricular system
blockage in arachnoid granulations

1: limited compensation in CSF+blood to maintain constant intracranial volume

2: compensatory mechanisms: vein collapse
arteriole constriction
displaced CSF into spinal column

3: eventually moves into brain and ICP rises→herniation

Hydrocephalus

excessive accumulation of CSF in ventricles or subarachnoid space

ventricular obstruction→noncommunicating hydrocephalus
ventricles can’t communicate
allows CSF to circulate
ventricles proximal to obstruction dilate

arachnoid grannulation obstruction→communicating hydrcephalus
ventricles communicate
all ventricles dilate
CSF not reabsorbed

Cardioembolic Ischemic Stroke

infarct stroke

PP: thrombotic/embolic occlusion of major vessel

E: Atrial fibrillation
thrombus from MI
mechanPP:ical valve
rheumatic MS

CM:

Large Artery Atherosclerotic Stroke

infarct stroke

PP: Plaque ruptures with artery-to-artery embolization

E: Medium to large arteries: junction of common carotid and internal artery
middle cerebral artery
vertebral artery
midbasilar artery

Transient Ischemic Attack

infarct stroke

PP: focal ischemic cerebral neurologic deficits last 1-2 hours (less than 24 hrs)

E: Emboli
plaque, fibromuscular dysplasia
polyarteritis
GCA
stenosis of arteries, polycythemia
sickle cell

CM: Acute onset
rapid recovery
rarely LOC or acute confusion

DX: CT or MRI+diffusion-weighted sequence within 24 hours
carotid duplex
MRA/CTA for vasculature
CBC
fasting blood glucose
cholesterol
EKG

TX:
NP: prevent further attacks/strokes
prevent smoking

MX: anticoagulants
statins

ABCD2 >4→take to hospital

carotid revascularization (high grade stenosis 70-99%)
-carotid endarterectomy
-endovascular intervention

Lacunar Stroke

PP: infarcts less than 1.5cm diameter

E: uncontroleld HTN
DM

CM: contralateral pure motor hemiparesis (paralysis on one side of body)
pure hemisensory deficit (no sensation on 1 side of body)
ipsilateral ataxia+hemiparesis

DX: CT
MRA

P: partial/complete resolution after 4-6 weeks

Cryptogenic Stroke

PP: unknown

E: atrial fibrillation+prolonged cardiac monitoring
antiphosphlipid
factor V leiden

CM:

Subclavian Steal Syndrome

PP: reverse flow of blood from this artery to supply arm→subclavian artery stenosis→vertebrobasilar insufficiency

E: exertion

CM: neurological sx

DX: doppler
ultrasound
MRI

TX: Carotid subclavian bypass
axillo-axillary bypass
percutaneous transluminal angioplasty with stent

Carotid Circulation Obstruction: Middle Cerebral Artery

lateral surface of frontal lobe
temporal lobe
parietal lobe

DMG:

temporal bilateral: Contralateral hemiplegia
hemisensory loss
homonymous hemianopia
eyes deviated to side of lesion

temporal dominant: global aphasia (broca/wernicke)

temporal non-dominant: Left hemispatial neglect syndrome
constructional/visuospatial deficits
speech/comprehension preserved

Ophthalmic or central retinal artery:
Amaurosis fugax: sudden transient vision loss in one eye
macular cherry red spot with retinal pallor

Carotid Circulation Obstruction: Anterior Cerebral Artery

medial surface of frontal/parietal lobes

DMG:
proximal: well tolerated

Distal:
frontal: weakness/sensory loss of contralateral leg
mild weakness of arm
urinary incontinence

Vertebrobasilar Circulation Obstruction: Posterior Cerebral Artery

occipital lobe
inferior temporal

DMG:
thalamic syndrome:
macular sparing homonymous hemianopia
mild/temporary hemiparesis
subthalmic nucleus (involuntary movements)

left occipital lobe+splenium of corpus callosum: Alexia (can’t read/understand language)

Vertebrobasilar Circulation Obstruction: Unilateral Vertebral Artery

anterior spinal+posterior inferior: clinically silent
small/atherosclerotic contralateral vertebral artery→deficit similar to basilar artery occlusion

posterior inferior cerebellar artery/vertebral artery before it branches:
lateral medullary syndrome (vertigo/nystagmus/sensory loss of face/dysphagia/limb ataxia/horner syndrome)
(contralateral sensory loss of limbs)

Vertebrobasilar Circulation Obstruction: Vertebral+Basilar Artery

Complete	coma with pinpoint pupils, flaccid quadriplegia, sensory loss, variable cranial nerve bad
Partial basilar artery occlusion	diplopia, visual loss, dysarthria, ataxia, weakness, sensory disturbance, CN palsy
Pontine	eyes deviate to paralyzed side
Hemisphere	eyes deviate to non-paralyzed side

Cerebellar

Cochlear infarction, anterior inferior cerebellar artery	deafness, vertigo, N/V, nystagmus, ipsilateral limb ataxia, contralateral spinothalamic sensory loss, ipsilateral FACIAL ST Sensory loss and weakness
Large infarction	hydrocephalus, coma, tonsillar herniation, death

Intracerebral Hemorrhage

PP: HTN→microaneurysms on perforating vessels

E: basal ganglia
pons
thalamus
cerebellum
ventricular system
subarachnoid space

CM:
cerebral hemisphere: lost consciousness
vomiting
focal signs+sx

putamen: loss of conjugate lateral gaze

thalamic: can’t look up
downward look of eyes
lateral gaze palsies
pupils different sizes\

cerebellar: nausea
vomit
disequilibrium
ataxia of gait/limbs/trunk
HA
loss of consciousness

pontine: lateral conjugate gaze palsy towards side of lesion
small pupils
contralateral hemiplegia
peripheral facial weakness
locked in signs: quadriplegia

DX: MRI
CT
CTA
MRA
venous thrombosis→CTV MRV
CBC
platelet
prothrombin are partial thromboplastin time
liver panel
kidney fxn
NO LUMBAR PUNCTURE

TX:
LOWER HTN to 140 with labetalol or nicardipine

ventricular drainage, surgical decompression, reverse coagulopathies

Subcutaneous Subarachnoid Hemorrhage

PP: traumatic→injury

nontraumatic→berry, arteriovenous malformation

E: trauma
nontraumatic

CM: thunderclap headache
nausea
vomiting
loss of consciousness

DX:
CTA stat: determine source

LP: Xanthochromia is the lysis of RBCs upon entry to CSF > 2000

TX:
Hospitalization for 2 weeks: no straining/exertion
treat sx of HA and anxiety
lower BP
Prevent vasospasm

Arteriovenous Malformations

PP: tangled arteries and veins

CM: intracranial hemorrhage
seizures
focal neurologic deficit
intractable headaches
found on brain images

DX: CT scan
MRI
CTA
MRA
brain images

TXT: remove lesion
endovascular embolization
radiation
surgery (maybe worse for unruptured)

Epidural Hematoma

PP: Space collection of blood and clot between dura and skull
lenticular biconvex shape

E: Middle meningeal artery (“MMA leads to this hematoma”
dural venous sinus

CM: loss of consciousness
lucid interval then rapid clinical deterioration

DX: CT

TX: neurosurgery

C: expansion can turn into herniation

Subdural Hematoma

PP: collection of blood between dura and arachnoid mater
concave shape

E: Bridging veins

CM: minimal deficit

DX: CT

TX: nicardipine
labetalol

Coma

PP: complication of CNS disorder

E: seizures
hypothermia
metabolic disturbances
meningoencephalitis
structural lesions
compression of brainstem

CM:
abrupt onset:
SAH
brainstem stroke
ICH

slower onset: structural mass or lesion

DX: serum
ABG
toxicology studies
non contrast CT
CT angiogram
LP

TX: thiamine IV+dextrose IV+naloxone IV