Clin Med - Stroke Flashcards
Impact of stroke
- stroke is the second leading cause of death worldwide
- 5th leading cause of death in the U.S.
- # 1 cause of adult disability
- nearly 800,000 new stroke cases/year in U.S.
Oklahoma stroke rate
4th highest in US
Define stroke
- 2 types
a sudden brain dysfunction related to a blood vessel abnormality
- ischemic
- hemorrhagic
Define ischemic stroke
diminished blood flow to a FOCAL area of brain; primarily thromboembolic
-85% of strokes are ischemic
Define hemorrhagic stroke
- rupture of intracranial vessel that is NOT due to trauma
- intracerebral (10%): usually hypertensive
- subarachnoid (5%): usually ruptured aneurysm
Define transient ischemic attack (TIA)
- transient episode of neurological dysfunction caused by focal cerebral ischemia without infarction
- time duration is no longer part of definition (but typically lasts 5 to 20 minutes)
- increased risk of stroke
TOAST criteria
-large artery atherosclerosis (extra/intracranial)
-cardioembolism (afib, LV thrombus)
-small vessel occlusion (lacunar strokes)
-stroke of other determined etiology (i.e.
venous thrombus)
-stroke of undetermined etiology (after extensive workup) 20-30% have paroxysmal afib
What are the 2 kinds of hemorrhagic stroke?
- Intracerebral Hemorrhage (ICH)
2. Subarachnoid Hemorrhage (SAH)
Causes of intracerebral hemorrhage (ICH)
- chronic Hypertension - #1 cause
- amyloid angiopathy
- ischemic stroke with hemorrhagic transformation
- venous infarct with 2* hemorrhage (sagittal sinus)
- coagulopathies
- arteriovenous malformation (AVM)
- illicit drug use (cocaine is MC, meth in Oklahoma)
ICH presentation
- often HA, vomiting, altered level of consciousness, and a focal deficit.
- sx vary depending on the area of the brain affected and the extent of the bleeding
- may present as new onset of seizure
- HTN is usually a prominent finding
Define patient presentation in subarachnoid hemorrhage (SAH)
The patient experiences a characteristic, intense, unrelenting headache of sudden onset often described as “the worst headache of my life!”
-may have transient loss of or altered consciousness
What is MCC of SAH?
Ruptured aneurysm is the most common cause of spontaneous SAH.
Targeted history in stroke recognition
-presentation
In general, tends to present with the sudden and immediate onset of symptoms, usually reaching maximal intensity at once
Targeted history in stroke recognition
-risk factors
DM, HTN, CAD, Hyperlipidemia, Afib, Smoking
-exact time of onset or if it was not a witnessed event, time they were last known to be normal
Stroke clinical pearl
-abrupt onset
Abrupt onset = strong predictor of stroke diagnosis
Cursory Neuro Exam
- Mental Status
- Language/Speech
- Gross Motor Function
- Visual fields/gaze
- Sensation
- Coordination
- Are there any focal or lateralizing deficits?
Level of consciousness
-alert and oriented
Alert, attentive, following commands.
If asleep, awakens and remains attentive.
Level of consciousness
-lethargic
Drowsy but will awaken to stimulation.
Slow to
answer questions or inattentive.
Level of consciousness
-obtunded
Difficult to arouse, needs constant stimulation to follow commands.
Will fall back to sleep without stimulation
Level of consciousness
-stupor
- patient needs vigorous and continuous stimulation
- often requires painful stimuli
- will NOT follow commands
- may moan and withdrawal from pain
Level of consciousness
-coma
No response to painful stimuli, no verbal sound, reflexive movement only.
Which stroke involves loss of consciousness?
Loss of consciousness not normally seen with acute ischemic stroke - must have bilateral hemispheric or brainstem involvement
What 2 types of language/speech are you evaluating for?
Aphasia and dysarthria.
Define aphasia
“Can they repeat,
understand, name, and can they speak?”
A language problem, very localizing.
Define dysarthria
“Slurred speech”
It is an articulation problem, not localizing.
Gross motor function
-assess face and extremities
-ask pt to smile: easy way to detect unilateral facial weakness
- have pt hold both arms straight out with palms up, If you observe pronation or a turning inward of the arm, that is a pronator drift
- Ask them to raise their leg (if seated-raise knee)
-use noxious stimuli (i.e. pinch the arm) in the obtunded or unresponsive patient to look for asymmetrical grimace or withdrawal
Clinical pearl
-gross motor function
Pronator drift/asymmetrical weakness strong predictors of stroke diagnosis
Visual fields/gaze assessment
- finger counting or by threat
- can also check for visual neglect at the same time
- are the eyes deviated?
- is the gaze conjugate, do the eyes move together?
- look for nystagmus – vertical or bidirectional = central cause
Clinical pearl
-visual fields/gaze
Abnormal Visual Fields and Gaze Deviation
– strong predictors of stroke diagnosis
Sensory function
-light touch
- can they feel light touch equally on both sides of the body?
- ask pt to close eyes and then touch both arms at the same time
- ask patient where they felt it.
- not only is this a brief sensory test, you are also testing for neglect
Sensory function
-sharp/dull
can they distinguish between a sharp or dull object on both sides of the body?
Coordination assessment
Test finger to nose (looking for dysmetria- ataxia) and heel to shin.
If cerebellar stroke is suspected (i.e. patient presents vertigo, you must test their ability to walk)
Clinical pearl
-coordination
bidirectional nystagmus and sudden inability to walk are strong predictors of a cerebellar stroke
Decreased LOC
-gaze
Gaze: eyes look towards the cerebral lesion // eyes look away from a brainstem lesion.
Check for dolls eyes, useful to assess brain stem.
Pupils - will see changes in metabolic/toxic conditions, will be symmetrical.
Decreased LOC
-response to pain
+/- Babinski
Check response to pain - asymmetric grimace, withdraw of extremities
Check for presence of a Babinski- usually a late finding
The National Institute of Health Stroke Scale (NIHSS)
- Level of consciousness
- Gaze
- Visual fields
- Facial strength
- Arm strength
- Leg strength
- Limb ataxia
- Sensation
- Language
- Dysarthria
- Extinction/inattention
Maximum Score = 42
Clinical features (3) -acute ischemic stroke
- Sudden onset of focal neurological symptoms: usually maximal at onset
- Signs should fit within defined vascular territory:
- Hemisphere: cortex or subcortical
- Brainstem and/or cerebellum - Rarely associated with loss of consciousness
5 major stroke syndromes
- left hemisphere
- right hemisphere
- ICH
- cerebellar
- brainstem
Stroke Syndromes Simplified
-hemispheric
Contralateral deficits of face and body
Aphasia – Left
Neglect – Right
Stroke Syndromes Simplified
-brainstem
Contralateral hemiplegia with ipsilateral cranial nerve deficits, diplopia, dysarthria
Stroke Syndromes Simplified
-cerebellar
Balance (trouble walking) and unilateral coordination difficulties
Stroke Syndromes Simplified
-hemorrhage
Headache, N/V, decreased LOC
ICH – Focal neuro deficits
SAH – neck stiffness/pain, light intolerance
Stroke treatment
- 3 strategies
- IV tPA
- Endovascular therapy
- Medical management
Stroke tx
- IV tPA
Gold standard in ischemic stroke care - give within 4.5 hrs
Stroke tx
- endovascular therapy
Mechanical disruption or removal of clot using endovascular approaches
Stroke tx
- medical management
Monitor and provide secondary stroke prevention
What are of the brain are we trying to save in stroke?
The penumbra
Define penumbra
- zone of reversible ischemia around core of irreversible infarction
- salvageable in first few hours after ischemic stroke onset if blood flow is restored
- damaged by hypoperfusion, hyperglycemia (100-180), fever and seizures
General emergency management
-ABC’s
- intubation - ensure adequate ventilation and protect airway in comatose patients
- monitor vital signs, cardiac rhythm, O2 sat% (keep > 94%)
- IV fluids: normal saline
- Improve perfusion
- Cursory Neuro exam
- Diagnostic studies
Emergency Diagnostic Studies
- FSBS
- Blood chemistries
- Brain imaging – Noncontrast CT or MRI
- Electrocardiogram
- Complete blood count and platelet count*
- INR and aPTT*
*only wait for labs to come back if you suspect pt is bleeding or on warfarin - otherwise start tPA immediately
CT’s role in stroke
- necessary to differentiate ischemic versus hemorrhagic stroke (clinical exam alone cannot distinguish between the two)
- necessary to rule out other possible cause of symptoms
*Always start with non-contrast scan!
CT Advantages
-fastest mode of any imaging
-almost universally
available in all hospitals
-no absolute contraindications
-excellent display of bone
-very high sensitivity for
hemorrhage (100% for ICH and 90% for SAH)
CT disadvantages
- poor for evaluating the posterior fossa
- poor sensitivity in the identifying early ischemic changes
NOTE: A normal CT does not rule out an ischemic stroke
General Management of SAH
- Surgical clipping or endovascular coiling of the ruptured aneurysm to stabilize it.
- BP control – target BP changes after aneurysm is secured
- Maintain euvolemia - avoid hypervolemia
- Meds: Nimodipine – x 21 days
MRI lesion descriptions
- the MRI lesions are described in terms of their signal intensity:
1. low signal intensity lesions are dark
2. high signal intensity lesions are bright
Advantages of MRI
- no radiation
- extremely sensitive to early (within 5 min.) or old ischemic changes and infarction
- much better visualization of the entire brain (especially the posterior fossa)
Disadvantages of MRI
- contraindications in some patients (metallic implants, pacemakers, claustrophobia, etc.)
- prone to artifact
- longer acquisition time
Acute Findings for Ischemic Stroke on MRI
- DWI and ADC changes persist for 10-14 days
- flair signal changes last indefinitely
Medical Management of ICH
-ABC’s
- Maintain oxygen saturation ≥ 94%
- Intubation for decreased LOC/inability to protect airway
Medical management of ICH
- BP reduction (target SBP < 140)
- treat any hyperthermia (<37.5oC) with Tylenol, cooling blankets
- glycemic control
- coagulopathy correction (for INR > 1.4)
- no corticosteroids
- secondary complication prevention
Acute Ischemic Stroke Intervention
-optimize cerebral perfusion
Support normal physiology to enhance collateral blood flow.
-Oxygen, temperature, glucose, permissive HTN
Acute Ischemic Stroke Intervention
-restore blood flow
- IV tPA up to 4.5 hrs
- Endovascular Therapy (EVT): up to 24 hrs depending on certain imaging
Optimize Cerebral Perfusion (Save the Penumbra)
-do’s and don’ts
- DO NOT treat elevated BP (unless exceeds goals)
- AVOID hyperglycemia (>180); use NS in IV (No glucose in IV - unless hypoglycemic)
- DO keep the head of the bed at 0 -15 degrees
- DO use supplemental oxygen to keep O2 sat. > 94%
- DO treat any temp elevation
What trial established tPA as the gold standard?
NINDS tPA trial in 1995
Limitations of IV tPA
- multiple exclusion criteria
- narrow therapeutic window
- risk of cerebral and systemic hemorrhage
- often ineffective for large vessel occlusions
- treatment rate only 7% (in 2011)
Acute Stroke Intervention
-when to use endovascular therapy (EVT)
- for use in certain patients up to 6 hours from stroke onset
- tx guidelines based on 5 recent clinical trials that showed significant benefit of EVT in treating large vessel occlusions
Stent retrievers
- generation
- definition
- 3rd generation endovascular stroke treatment
- they immediately restore flow
- trap thrombus within stent and retrieved
- they are a removable device (no anti-platelets needed)
AHA/ASA Recommendations for EVT
- age > 18
- NIHSS score > 6
- Documented large vessel occlusion (LVO) in the anterior circulation: distal ICA or proximal MCA
- onset to groin puncture within 6 hours
When the moon hits your eye like a big pizza pie,
that’s amore…..
When you swim in a creek and an eel bites your cheek,
that’s a moray
:) :)
