CM II - 10 Stroke

what is a stroke?

blood supply to part of brain is suddenly interrupted or when a blood vessel in brain ruptures

what is a good prognostic sign of a stroke?

if they are awake

what is a thrombus?

clot forms inside cerebral circulation

what is an embolus?

a LOOSE clot or fibro-fatty plaque travels outside the cerebral circulation → brain until it becomes lodged in a artery

what can cause a hemorrhagic stroke?*

rupture of blood vessel (arterial defect or trauma)*

what are the types of stroke?

• transient ischemic attack (TIA) (Reversible)

• residual ischemic neurologic deficit (RIND) (reversible)

• cerebrovascular accident (CVA, completed stroke = resulted in permanent/irreversible dmg to brain tissue)

what is the most common type of stroke?

ischemic (80-85%), specifically thrombotic (50-60%)

what can cause thrombotic stroke?

large or small vessel disease

what is involved in large vessel disease?

extracranial and intracranial blood supply to brain → athero-thrombosis

what is involved in small vessel disease?

smaller penetrating arteries of brain that results in small, deep infarcts called lacunar infarcts/subcortical strokes → lipohyalinosis or local atherosclerosis

below the cortex?

what is lipohyalinosis?

plug formed by lipid and denatured protein

not a true thrombus!

what are features of a thrombotic stroke?

1. preceded by TIA

2. occurs during sleep → findings present upon awakening

3. abrupt onset

4. stepwise progression → stroke in evolution

5. not visualized by non contrast brain CT in early hrs of stroke

what is the most important predictor of stroke?

severity of neuro signs (ie prolonged unconscious, which is the biggest predictor)

what are non-modifiable RF for stroke?

• heredity

• age

• gender (women)

• ethnicity (african american)

• previous stroke or transient ischemic attack

above this is intracranial, anything below is extracranial. what is this?

foramen magnum

what are modifiable RF for stroke?

• HTN: most prevalent RF

• Heart disease

• DM

• cigarette smoking (even if they don’t have high BP)

• hyperlipidemia (micro/macro issue)

• alcoholism (can cause heart issues d/t low cardiac output)

• polycythemia/thrombocythemia (too many RBC = blood sludgy)

in diabetes, what contributes more to prevention of stroke than control of blood sugar?

blood PRESSURE

what is the most prevalent RF for stroke?

HTN

what is the definition of TIA?

• < 24h, usually <5 mins (which is why they tend to get better)

• if >24 h = RIND

• >1 hour = assoc. brain infarction

what is the pathophysiology of TIA?

1. plt aggregation/showering of emboli of clumped platelets/plaque

2. intermittent blockage of circ/vasospasm (d/t released vasoactive substances from activated plts)

w/o tx, 80% have recurrence

what is the ABCDD scoring system?

used to predict CVA risk AT TIME OF PRESENTATION within 48 hrs of TIA

• Age (>60 yo = 1 pt)

• BP (140/90 = 1 pt)

• Clinical features (unilateral weakness = 2 pts; isolated speech disturbance = 1 pt; other = 0 pt)

• Duration of TIA symptoms (>60 m = 2 pt, 10-59 min = 1 pt, <10 min = 0 pt)

• Diabetes (present = 1 pt)

score 6-7 = 8% risk, 4-5 = 4% risk, 0-3 = 1% risk

what are the 3 main subtypes of ischemic stroke?

• thrombotic

• embolic

• lacunar (special subtype of ischemic)

what is the point of doing a CT scan if usually you can NOT see ischemic strokes in the first 12 hrs?

checking for intracranial bleeding, abscess, and tumor

what is an embolic stroke?

Refers to particles of debris originating elsewhere that migrate and eventually come to rest at a point in which they block arterial circulation to a particular brain region

what are sources of emboli?*

CARDIOEMBOLI

• afib, MI, endocarditis, rheumatic HD, valvular prosthesis, ASD/VSD → EKG/echo

ARTERIAL ORIGIN

• aorta, carotids, vertebrobasiliar circ → carotid doppler

NON-ARTERIAL ORIGIN (venous side often, so don’t cross to arteries)

• fat, air, tumor, hardware, paradoxical, septic emboli

what are the features of embolic stroke?**

1. sudden onset

2. rapid progression** (not really evolution seen in thrombotic) of sx

3. syncope or seizures

4. maximal def at time of presentation

what must you always assume in a stroke?

embolic source and we have to keep looking until we are satisfied there is not

what is the work up for ischemic strokes?**

• CT scan (r/o hemorrhagic stroke)

• EKG

• transthoracic/transesophageal echo

• carotid/vertebrobasilar doppler US

what work up would you do for hemorrhagic stroke and individual cases of ischemic stroke?

CTA, MRA, and cerebral arteriography

what is a stroke due to hypoperfusion?

Stroke occurring as part of a general circulatory problem, manifesting itself in the brain and elsewhere

what can cause hypoperfusion stroke?

cardiac pump failure caused by

1. cardiac arrest

2. pulm (venous) embolism

3. pleural effusion

4. hemorrhage

5. septic shock

what is a watershed area?

watershed is like anastomose, so usually that’s good!

ie cortical border zone (b/w ACA and MCA), internal border zone (b/w lenticulostriate and MCA), and cortical border zone (b/w MCA and PCA)

what happens if you have an infarct in the watershed zone?

during hypotensive episodes, brain has WORSE ischemia (despite the anastomose) because the arteries lose flow simultaneously (esp DISTAL branch most effected)

cerebral cortex infarcts occur at the border zones b/w territories of 2 major arteries in the brain

where are the most common locations of watershed infarcts?

between anterior and middle cerebral arteries

what can cause ischemic strokes in younger pts?

• ARTERIAL: dissection, fibromuscular dysplasia/marfans/vasculitis, vasoactive drugs (cocaine!), migraine w/ aura

• paradoxical cardiac embolus (PFO)

• sickle cell disease

• hyperviscosity syndromes

• hypercoagulable states (Thrombophilias)

what are examples of hyperviscosity syndromes?

gammaglobulinemia and cold agglutinin disease

what are examples of hypercoagulable states?

inflammatory disorders like lupus (anti-phospholipid antibody syndrome)

what are lacunar strokes associated with?

vascular lesions in the posterior circulation (vertebral and basilar arteries) → in CN impairment or dysfunction of the descending motor or ascending sensory tracts within the brain stem

what is the most common type of ischemic stroke?

lacunar stroke

what causes lacunar strokes?

occlusion of small arteries that provide blood to brain’s deep structures in cortex/subcortex

d/t lots of pathways through narrow path → vertebrobasilar occlusions → myriad signs

what are s/sx of vertebrobasilar arterial disease?

1. Horner’s syndrome (ptosis, miosis, enophthalmos, anhidrosis)

2. Abnormal eye movements

3. Unilateral, bilateral, or crossed motor and sensory (including visual) abnormalities in the face, arm or leg

4. Ataxia

5. Dysarthria

6. Dysphasia

7. Behavioral and visual symptoms

8. Stupor or coma

what is not been shown to prevent lacunar strokes?

aspirin (good for clots w/ platelets but you don’t know what is causing the lacunar stroke)

what is the best tx for lacunar strokes?

aggressive management of risk factors (ie, HTN, hyperlipidemia)

no surgical options

what presentation of middle cerebral artery syndrome?

• eyesight

• sensory or motor?

• what else is lost?

• homonymous hemianopsia

• sensory and motor deficit of contralateral face, arm, leg (arm >leg)

• cortical function loss: dom side [SPEECH] = aphasia, agraphia, acalculia, alexia; non-dom side = neglect, apraxia, confusion

• gaze deviates toward infarcted hemisphere

what is alexia?

inability to read

what side of the brain is where the speech and language function reside?

LEFT side (MCA supply)

MCA - where is broca’s area?

anterior part of MCA

MCA - where is wernicke’s area?

posterior part of MCA

what is dysarthria?

damage to MOTOR control of mouth and tongue (precentral gyrus) → problems with DICTION of speech (can still produce and understand lang)

anterior cerebral artery syndrome (ACA) presentation?

• contralateral paralysis, sensory loss leg > arm

• apraxic gait (acquried disorder of motor planning so pt cannot perform tasks/movement, NOT d/t incoordination, sensory loss)

• return of contralateral grasp reflex, sucking reflex

ACA mostly perfuses what?

the medial side of cortex that goes deep into the fissure, that’s why legs are more affected if there’s a stroke here

what are some frontal lobe signs of ACA stroke?

lack of spontaneity, indifference

what happens if you have a stroke in the PCA?

occipital lobe and brainstem are affected

what would be presentation of occipital lobe stroke?

hemianopsia, cortical blindness, memory loss, nonspecific visual hallucinations

the hippo (hypo) never forgets means?

the hypocampus is responsible for long-term memory

if you have a stroke in the brainstem, what is the presentation?

3rd nerve palsy, hemiplegia, ataxia

what if you have a stroke in the VBA (vertebrobasilar artery)?

1. unilateral, bilateral, or crossed motor and sensory (incl visual) abnormalities in FACE, ARM, OR LEG

2. ataxia

3. dysarthria

4. dementia (after many strokes)

5. diplopia

6. dysphagia

7. drop attacks

8. vertigo, N/V

9. tinnitis

10. coma

what areas of the brain may be affected by a lacunar (subcortical) stroke?

• thalamus

• basal ganglia

• internal capsule

• pons

• inferior portion of occipital lobes

lacunar stroke where you see only motor issues in face, arm, and leg, where it is localized?

internal capsule

lacunar stroke where you see sensory issues in face, arm, leg, where it is localized?

thalamus

lacunar stroke with sensorimotor issues in face, arm, and leg, where is it localized?

thalamo-capsular

lacunar stroke where you see ataxic-hemiparesis, where is the localization?

basis pontis

lacunar stroke where you see clumsy hand dysarthria or incoordination, where is it localized?

genu (knee) of IC and pontine (pons) stroke

reminder: pons= breathing, sleep, facial movements, and communication between different parts of the brain.

lacunar stroke where you see multi-infarct dementia would be localized as?

multi-focal (usually cortex)

when liquefaction involves necrotic vasculature, what can it result in?

secondary hemorrhage with hemorrhagic infarction

basically ischemic stroke → hemorrhagic, and vice versa

what type of hemorrhagic stroke usually occurs in the setting of trauma?

epidural hemorrhage

what is an intracerebral hemorrhage?

bleeding into the parenchyma of brain

what are the RFs for intracerebral hemorrhage?

1. HTN!**

2. AVM (arteries connect to veins w/o connecting to a capillary bed)

3. arterial dissections

4. intracerebral aneurysms

5. trauma

6. excessive use of alc or sympathomimetics

7. smoking

8. ages 40-60

9. positive family history

10. africans and asians

where are the most common sites for hypertensive hemorrhage?

1. putamen of basal ganglia

2. thalamus

3. pons

4. cerebellar hemispheres

5. cortex and other subcortex

why does bleeding show up on CT?

the iron in the hemorrhage is dense

what is a major cause of subarachnoid (SAH) hemorrhage?

ruptured arterial aneurysms

where do ruptured arterial aneurysms commonly form?

circle of willis where major arteries branch apart (place where vessels penetrate the meninges, so the meningeal layer that is most affected is subarachnoid space b/c that’s where CSF is AND there is a spot of weakness in crux of branches)

= “berry aneurysm”

what precedes a rupture?

slow sentinel (“first guard/defense”) bleed

primary symptoms of slow sentinel bleed?

sudden, severe HA with meningeal signs/inflammation (N/V, stiff neck, brief LOC, seizure)

re-bleeding is common

what happens when blood gets out of a vessel?

clots and it triggers infection

what is a common phenomenon in subarachnoid hemorrhage?

post bleed vasospasm → secondary ischemic stroke damage

usually no focal neuro signs at time of presentation

what causes a subdural hematoma?

1. bleeding of bridging veins → venous bleeding does not accumulate rapidly and there is low pressure (forms between dura and arachnoid)

2. can be caused by head trauma (mild) → days/weeks/months later when pt has sx

what are the sx of a subdural hematoma?

HA, slight to severe cognitive impairment (dementia), hemiparesis, seizures, focal neuro signs in some pts, personality changes

why is epidural bleeding always arterial blood?

you have to tear the dura off the skull for the blood to collect over the dura (and you need high pressure in order to do that, so veins can’t do that)

subdural hematoma involves what kinds of blood?

can be caused by venous blood AND arterial blood

epidural hematoma is only arterial

if the leading edge is straight or it is a concave crescent in CT, what do you think it is?

the blood is collecting under the dural (gradually under low pressure) AKA SUBDURAL HEMATOMA

concave crescent is because you need more pressure in order to compress the middle of the brain

what would you see of a CT of epidural hematoma?

convex protrusion, deforms brain (accumulating under very high pressure)

convex is the opposite of crescent

what is tx for subdural hematoma?

1. If discovered incidentally → clinical monitoring 

2. If symptomatic and pts condition is worsening → surgery

what causes and where a epidural hematoma?

1. arises in space between dura and skull due to bleeding of a major artery

2. significant trauma → bleeding is arterial and rapid

what is a unique finding of epidural hematoma?

lucid interval before slipping into a coma

what is the usual cause of death of epidural hematoma?

brain herniation

what are supratentorial herniations?

1. Uncal → anterior extremity of the parahippocampal gyrus forced downward, pushes against cerebellum

2. Central → middle being pushed down

3. Cingulate → cingulate gyrus being pushed under falx and crossing midline

4. Transcalvarial → brain being pushed out a skull hole

the dura the dives down the two hemisphere fissures

falx cerebri

what are infratentorial herniations?

1. Upward → cerebellum pushed upwards

2. Tonsillar → cerebellum pushed downwards (does not require chiari malformation)

tx and prognosis of epidural hematoma?

• prognosis: better than others if treated in time

• tx: immediate surgery

can a subdural hematoma be chronic?

no, either it gets resolved or the pt dies

what are the ddx of stroke?

• migraine

• meningitis

• concussion

• seizure

• drop attack (cataplexy, caused by hyper-ammonia)

• brain tumor

• todd’s palsy (postictal condition)

• functional deficit

• toxic-metabolic disturbance (hypoglycemia)

what is cushing’s triad?**

inc intracranial pressure (ICP)

• HTN w/ widening pulse pressure

• bradycardia

• irregular respirations

what are indications of increased ICP?

• papilledema

• midline shift on CT/MRI

• unequal pupils

what are the steps of TIA or CBA evaluation?**

1. neuroimaging study (CT/MRI)

2. noninvasive imaging of carotid (doppler)

3. cardiac evaluation (EKG, echo, TEE)

what are the signs of stroke? (FAST)

• Face: drooped unilateral face?

• Arms: one arm drifting downward

• Speech: slurred/strange

• Time: call 911

steps of acute care of stroke pt?*

1. tx fever w/ antipyretics (inc metabolic consumption need for oxygen)

1. elevated HOB 30 degrees

2. if BP >220/120 → IV labetalol or nitroprusside

3. tPA

4. NPO until evaluated for dysphagia

when do you consider giving an ischemic stroke pt TPA?

1. pt presents within 3 hr of neuro deficit (after this time, you risk liquefaction → hemorrhage)

2. CT confirms absence of intracranial hemorrhage

3. NIH stroke scale 5-20

when is TPA usage in a stroke contraindicated?

1. hemorrhagic stroke, previous ICH, large stroke

2. major surgery within 2 weeks/recent bleeding

3. >185/>110

4. MI in past 3 months

5. INR > 1.7

6. Thrombocytopenia

where is the location of the middle cerebral artery?

temples!