Stroke, TIA, SAH Flashcards
Ischemic v. Hemorrhagic
where does a TIA, SAH, ICH fall
Ischemic: ishemic = ischemia (decrease flow) which can LEAD to infarction (tissue death)
- ischmic stroke is a result of a blood clot or narrowing of vessels which creates a decrease in neurological functioning
- ishemic: can be spinal, cerebral or retinal infarction = seeing death of tissue on brain imaging
TIA = a transient episode of neurologc dysfunction, due to brain ischmeia BUT NO EVIDENCE OF ACUTE INFARCTION on imaging
Hemorrhagic: weakened vessels which rupture and BLEED into surrounding tissue causing brain damage
SAH: subarachnoid hemorrhage (below arachnoid)
ICH: intracerebral hemorrhage (within the brain tissue itself)
Ischemic Stroke
thrombotic v embolic
Thrombolic: a narrowing of vascularture within the brain as a result of something INSIDE the brain vessle; usually a clot that FORMED THERE - in the brain
Reasons for a thrombus in the brain
- atherosclerosis
- vasculitis disorders
- hypercoaguable states
- infection
Embolic: obstruction of a normal vascular lumen in the brain; a result of material which came from somewhere else in the body and traveled there
- A fib (clot thrown from the atria)
- valvular vegitation (IVDU)
- cardiac tumor piece
- fat emoli
Vascular Anatomy
anterior circulation
posterior circulation
Anterior circulation
- the Left and Right interal Carotid arteries give rise to the right and left middle cerebral arteries (MCA) as well as the left and right anterior cerebral arteries
- the MCA supplies the lateral aspects (affecting face and hands > legs) and the ACA supplies the medial aspects (affecting legs and trunk > hands and face)
Anterior Circulation Supplies
- cerebral cortex
- Subcortical White Matter
- Basal ganglia, thalmus and hypothalmus (in combo with the PCA)
- the internal capsule
Posterior Circulation
- the left and right vertebral arteries enter and combine to form the basilar artery
- the basilar artery branches to form the left and right PCA: posterior cerebral arteries
- other branches include: PICA, posterior/anterior spinal, anterior inferior cerebellar and superior cerebellar
Posterior Circulation Supplies..
- cerebellum
- Brain Stem
- Spinal Cord
- parts of thalmus, hypothalmus, occipital and temporal lobes (in combo with the MCA)
Deficts in the Anterior Circualtion result in ….
Left sided defict
Right sided defict
Anterior circualtion = ACA and MCA
need to thing about which hemisphere is affected
if the LEFT hemisphere is affecting: detriments to the right side will include
- hemiparesis: motor deficts of facial weakness & horizontal gaze palsy TOWARD the side of the lesion (to the left)
- hemisensory deficts: of pain and temperature
- left sided deficts will also have significant speech issues since this is the dominant speech area for those right-handed (80%) : aphasia, apraxia and agnosia
if the RIGHT hemisphere is affected: detriments to the left side will include
- hemiparesis: facial weakness, horizontal gaze palsay toward the RIGHT
- hemisensory deficts: temperature and pain
- right sided deficts will also result in inattention/neglect of the left side, extinction and dysarthria without aphasia since language usually is on the left, the issue is just weakness of motor muslces not the speech centers!!!
both sides of an anterior circualtion defict can result in homonymous hemianopsia
results of a lacunar infarct
MCA (from anterior circulation) also help to supply the perforating vessels which supply the deeper structures of the brain ( basal ganglia, thalmus, hypothalmus)
- an occlusion of these smaller vessels can cause huge deficts out of proportion to the size of infarct, as these structures play a role in the relay process of signals
- can have pure motor or pure sensory deficts: ex. damange of the somatosensory projections from the thalmus can result in similar sensory issues as a larger vessel occlusion
Posterior Circulation Deficts result in….
specific to the PCA
cerebellum
vertebrobasilar
basilar
(left or right doesnt really matter here as they supply same structures)
brainstem or cerebellar dysfunction = difficult to pick up, espeically since NIHSS tests more of the motor and sensory deficts seen with an anterior stroke
Common symptoms (regardless of the exact artery include)
- vertigo & dizzy
- N/V
- same sided facial deficts
- opposite sided limb deficts
- swallowing difficulties
PCA: opposite sided homoynous hemianopsia, unliateral HA, sensory deficts, inability to read, inability to name colors, unilateral CNIII palsy
Cerebellum: HA, N/V, vertigo, gait instability, limb ataxia, dysarthria
Vertebrobasilar: vertigo, occular palsies, visual issues, swallowing issues, ataxia, dipolpia, horners
Basilar: quadriplegia, coma “locked- in” syndrome, vertical upward gaze
TIA: transient ischemic attack
what is it
what does it imply
Risk Factors
TIA: a transiet (short-lived) episode of neurologic dysfunction: due to brain ischemic but NO EVIDENCE OF ACUTE INFARCTION on brain IMAGING
- this is an EARLY warning sign: that a stroke is coming; high risk for a stroke in the following days, weeks, months etc.
RISK FACTORS
- high cholesterol
- DM
- HTN
- current smoker
- OSA, obestiy, metabolic syndrome, poor diet, etc.
- stressors in life
- alcohol consumption
- cocaine use
- A fib: throwing a clot to the brain from the heart
- valvular heart disease; PFO, vasculitis
- hx. of TIA stroke (or family hx.)
- giant cell arteritis
TIA
Symptoms
Reasons for a TIA
Symptoms
- sudden onset with quick resolution of symptoms (usually less than 24 hours)
- focal or unilateral neurological defects of motor or sensory symptoms
- these symptoms or stroke like things will go away after the TIA is over (although lasting effects are possible)
other symptoms
- increase HR, BP, carotid bruits, etc.
Reasons
- tumor
- CNS infection
- syncope/fall/trauma
- hypoglycemic/metablic disturbance
- MS
- SAH (with addition symptom of HA)
Symptoms of TIA v a mimicking event (seizure, etc.)
TIA
- will have unilateral paresis
- will not have memory loss
- will have dysarthria
- may have double vision or monocular blindness transiently
-
Workup of a TIA
labs
imaging
differentiate between what and waht types
score calcultor for stroke risk? for a fib clot induced stroke risk
evaluation must occur within 12 hours completed by 48 hours
- CT or MRI (within first 24-48 hours)
- brain vasculature imaging (carotid imaging, doppler or MRA needed)
- EKG & echo
- labs: CB, a1c, lipids, CMP
need to find underlying source, is it embolic (from a fib clot) or thrombotic from atherosclerotic origins
Scores
ABCD2 Score: determines the short-term risk of pt. having a stroke within 2-90 days of the TIA event
score > 4 = probably should hospitalize to watch for stroke risk in next 2 days
score > 6 = definately neeed to hospitalize
CHA2DS2-VASc Score: determines the risk of a clot being thrown from A fib (to see if anticoag. is needed)
TIA
Management
Medications
antiplatelet v anticoag.
TIA: need to assess and address other factors which increase likelihood of a TIA & stroke
- HTN management
- lipid management
- DM control
Antiplatelet Thearpy: if the cause is atherosclerotic in origin; daily long-term antiplatelet
- asprin as monothearpy
- asprin allergy –> clopidogrel (get labs to see if responsive to clopidogrel)
- clopidogrel resistant –> ticagrelor
HIGH RISK PTS: need dual therapy with aspring + clopidogrel or asprin + ticagrelor (unless GI bleed risk)
Anticoagulation Therapy: if the cause is A. Fib throwing clot in origin (to prevent that) long term anticoag. needed
DOACS are first line for anticoagulation
- apixiban > dabigatran or rivoroxaban
- warfarin can be used but D-D interactions and needs monitoring of INR
- unable to anticoag. –> need watchmans device or surgical ligation
HTN and Lipid goasl for our TIA pts.
HTN: want BP < 130/90
- ACE +/- diuretic, or an ARB
Lipids
- statin thearpy
- LDL< 100 (if atherosclerotic pt. want < 70)
- 50% reduction desired
smoking cessaion, exercise, reduce alchol and hange diet can all help
Ischemic Strokes
- causes
- pathogenesis
Ischemic Stroke: ischemic tissue leads to infarction (due to blockage)
Causes
- A fib: a clot is thrown and gets stuck (blocks flow)
- atheroscelrosis: narrowing of the vessels
- lacunar (small vessel) infarctions
- systemic hypoperfuction (cardiac arrest, overdose, etc.)
majority of the strokes which occur are in the large arteries in the anterior or posterior circulation
Pathogenesis
- occulded blood flow = no oxygen
- ischemia develops when there is less than 20% blood flow to the area than normal (at 80% flow its ischemic)
- this border of ischemic tissue is called the penumbra – this is the area that if help is gotten, could be restored and not dead “the at risk of dying if not helped area”
ischemic strokes can evolve to become…
1. Vasogenic: inflammation continues after the stroke
- leading to hernation, or death if infarction is large enough
- symptoms will worsen after stroke
- Hemorrhagic transofrmation: begin to bleed
- result of BBB disrupted, capillaries disrupted, HTN or reperfusion goes wrong
- dramatic decline in symptoms
Ischemic Stroke
Symptoms
symptoms depend on the area in which the stroke is occuring: infarcted tissue in different areas will ahve different presentations
Thrombotic: ususally a step-wise or gradual progression to their worst
Embolic: will be abrupt and max insult will be immediate
Anterior Cerebral Artery Occulsion: ACA Stroke
symptoms
ACA: supplies the medial frontal lobe: specifically in the motor and sensory hommunculs (the LE»_space; UE and face)
Symptoms
- Lower extremity weakness and lost sensation more than upper extremity and facial symptoms on the contralateral side (since we know that they cross at the medulla)
- paracentral lobule: urinary urgency/incontinence
- limbic/prefrontal cortex supply: AMS, disinhibition, impaired judgement
- (speech of prefrontal cortex): speech peserveration (repeating), nonfluent speech but comprehension is ok
Middle Cerebral Artey Occlusion: Symptoms
MCA: supplies the lateral sides of the frontal, parietal and temporal lobes
most common type of stroke M1 occulsion v M3/M4 can differntiate symtpoms
Symptoms
- hitting the lateral hommunculus: so youll see issues with facial and upper extremitiy motor and sensory abilities on the contralateral side of the stroke
- speech: aphasia if left MCA
- hemineglect: if right MCA
- gaze preference to the side of the lesion (side the opposite side controls the opposite eye: therefore if there is a R sided stroke, controlling left eye field, cant look that way, looks right)
homonymous hemianopia
Internal carotid artery Occlusion
symptoms
** can be asymptomatic if there is collateral circulation which is adequate**
- preceeding amarousis fuax (transient monoccular blindness) possible
- dizzy, sudden and severe HA possible
- contralateral sesnsory and motor deficts
Subcortical/Lacunar Infarct
risks
syndromes
those branches off the MCA which travel to the deeper parts of the brain: supplying internal capsule, basal ganglia, thalmus or brainstem
Risks: HTN, smoking, DM, lipids
Symptoms (5 classic syndromes)
- pure motor stroke: only motor weakness
- pure sensory stroke: only sensory loss
- mixed sensorimotor
- ataxic hemiparesis
- clumsy-hand & dysarthria (speech) : brainstem stroke
other Lacunar Infarcts: can be asymptomatic (clincally silent)
- can present with acute or subacute symptoms (those above)
- okay prognosis but can worsen
Watershed Infarct: Bilateral
what is it
symptoms
Watershed Infarct
- the junction between the two arterial areas of the ACA and the MCA
- usually a result of poor perfusion: lacking blood flow to both these arteries results in a “no mans land” of no oxygen getting to these sites
the resulting zone: is
- proximal UE motor and sensory loss of the contralateral side (usually abilaterally occurence)
- the extremities (face, hands, legs and feet) are ok
- “man in barrel syndrome” as the trunk is effected
Posterior Circulation Strokes: Posterior Communicating Arterty Occulsion
Symptoms
PCA Stroke: most commonly due to an embolsim: from the heart
Symptoms
key one: contralateral homonymous hemianopsia = most common due to infarct occuring in the occipital lobe regions impacting the contralateral side of vision
- headaches (common)
- limb weakness
- dizzy, nausea
- memory loss
Thalmaic Syndrome
- contralateral hemisensory disturbance: paresthisias of face, limbs and trunk (becuase thalmus is relay)
- spontaneous pain
Vertebrobasilar Occulsions
symptoms
Vertibrobasilar Occulsions
- the verterbal artery - basilar artery junction = site of occlusion (just before the PICA) is the most common location
- this impacts the cerebellum and the brainstem
Symptoms
- asymptomatic (if good collateral flow)
- TIAs or Horner’s Syndrome possible
Locations or types of this inarct
- lateral meduallary infarct = wallenburg
- medial meduallary infarct
- cerebellar infarcts of PICA
- basilar infarct via embolsim or thrombosis
Basilar Artery Occlusion
symptoms
Basilar Artery: the combo of the two vertebral arteries which is formed right at the pons & impact cranial nerves!!
(supplies cerebellum and pons)
Symptoms
- dysphagia & dysarthia (motor and comprehension issues)
- tongue/palate deviation
- EOM deficts
- ataxia (cerebellar dysfunction)
- crossed sensory/motor deficts: same side of face but opposite side of body
think basilar arteries: supplying pons & inside the pons is…
- in the pons, the contralateral sensation has already crossed over (in medulla) so lack of sensation on the contralateral side
- in the pons, the same side of the cranial nerves for sensation and motor of the face via the trigeminal nerve
locked-in syndrome : in tact consciousness but in ability to speak and move because the pons is damanged (conscious becuase the reticualr formation is perserved)
PICA occulsion
symptoms
PICA: posterior inferior cerebellar artery
supplies the posterior and inferior cerebellum
results in
- cerebellar infarct
- vertigo and nystagmus
- n/v
- ipslateral limb ataxia and numbness and headache
high risk of hernation of the brain and coma progression
Wallenberg Syndrome
(lateral meduallary syndrome)
occlusion in…
- PICA or vertebral artery
Symptoms
- contralateral pain and temperature sensation issues of upper and lower extremities (as a result of the spinothalamic tract)
- contralateral motor fuction is ok, since motor travels through the corticospinal fibers & these are more ventral (below) where this is occuring
- vertigo and nystamgus (to the affected side)
- N/V & hiccups (uncontrolled)
- CN IX, X issues will speaking, and gag reflex
- horners syndrome (sympatheitc fibers injured)
- ataxia towards same side of lesion
- imparied facial sensation on the same side as lesion (but not motor since these arent near medulla and already have left)
