CVA/Stroke Flashcards
Concepts & Pathophysiology
Priority: perfusion
Interrelated concepts: cognition, mobility, sensory perception
- Brain tissue, blood, & CSF occupy the skull
- If 1 increases, others dec to maintain equilibrium
Causes
- Blockage of a blood vessel
- Ischemic stroke
- Bleeding into the brain
- Hemorrhagic stroke
Stroke Risk Factors: Modifiable
- HTN ! most common risk
- DM/obesity/cardiovascular (afib, PFO)
- Illicit drug use esp cocaine
- Smoking/heavy alcohol use
- Sleep apnea
- Aneurysm
- Hormone use/oral contraceptives/anticoags/anti-platelets
- Preeclampsia
- Use of phenylpropanolamine (PPA) used in antihistamines
Non-Modifiable
- Age >55
- Race > African Americans
- Gender > women
- Family medical hx
There is often a zone of tissue surrounding an infarction called the ___ ___ that contains ischemic tissue that is not irreversibly damaged
ischemic penumbra
Ischemic stroke
- Sudden blockage of a cerebral blood vessel
- Causes reduction of oxygenated blood to the brain, resulting in an abrupt onset of clinical manifestations
- Ischemic penumbra
- Cerebral blood vessels may be opened or recanalized using IV recombinant tissue plasminogen activator (IV rt-PA)
> Authorized to treat acute ischemic stroke
> Allows a blood clot to be dissolved @ the site
> Restores blood flow to ischemic neuronal tissue
?
This intervention involves a cerebral angiogram to locate a vessel occlusion accompanied by delivery of thrombolytics directly into a blood clot
Intra-arterial thrombolytic administration
Measures to prevent complications of stroke
- VTE prophylaxis
- Management of BP
- Control of stroke risk factors to prevent recurrence
Complications
! Hemorrhagic transformation can be life threatening
- Cytotoxic edema
- Weakness or paralysis
- Disorders of speech d/t facial muscle or CN weakness
- Apraxia (difficulty w/skilled movement) [from inj to frontal & temporal lobes]
- Depression [d/t right hemisphere involvement]
Hemorrhagic Stroke (3 subtypes)
- Nontraumatic subarachnoid hemorrhage (SAH)
- Intracerebral hemorrhage (ICH)
- Intraventricular hemorrhage (IVH)
Medical & surgical management
- Cerebral vasospasm occurs in approx 30% of pts w/SAH & causes narrowing of blood vessel segments
- Surgical evacuation of a hematoma below the tentorium, infratentorial, is gen rec b/c of risk of brainstem compression & irreversible brain inj
?
Is thought to occur as a result of an inherent weakness or gradually acquired weakness of the medial layer in a segment of a blood vessel
cerebral aneurysm
?
Is typ c/b a ruptured aneurysm (weak, dilated vessel) & less commonly by AVM which is a mass of arteries & veins that is not connected by a capillary network
Subarachnoid hemorrhage
?
May also occur as a primary site of hemorrhage
Is typ managed using medical therapies to manage BP & prevent expansion of the hematoma as well as therapies to reverse coagulopathy & treat IICP (e.g., osmotic therapy, hyperventilation, drainage of CSF)
Intraventricular hemorrhage
Administration of ____, a calcium channel blocker, improves outcomes in pts experiencing vasospasm; h/e, this drug is assoc w/hypotension, which may necessitate alteration in dosing by inc the freq of dosing & dec the dose or discont the therapy in some instances
nimodipine
Hyponatremia is a common complication in pts w/SAH, which may be c/b SIADH or by cerebral salt wasting synd, aka renal salt wasting synd
- Myocardial ischemia & infarction, ARDS
?
Localized cerebral ischemia that causes neurological deficits lasting <24 hrs (usually <1-2 hrs)
Causes: inflammatory arterial dz (vasculitis), sickle cell anemia, atherosclerosis, thrombosis, emboli
“warning sign”
Transient ischemic attack (TIA)
Visual deficits
- Blurred vision
- Diplopia (double vision)
- Blindness in 1 eye
- Tunnel vision
Mobility (motor) deficits
- Weakness (facial droop, arm or leg drift, hand grasp)
- Ataxia (gait disturbance)
Sensory perception and speech deficits
- Numbness (face, hand, arm, or leg)
- Vertigo
- Aphasia
- Dysarthria (slurred speech)
TIA: Important Factors
- Low blood flow @ a narrow part of a major artery carrying blood to the brain, such as the carotid artery
- A blood clot in another part of the body (such as the heart) breaks off, travels to the brain, & blocks a blood vessel in the brain
- Narrowing of the smaller blood vessel in the brain, blocking blood flow for a short period of time; usually c/b plaque (a fatty substance) build-up
Important facts to keep in mind
- 40% of people who have a TIA will have an actual stroke
- Nearly half of all strokes occur within the first few days after a TIA
- Sx’s for TIA are the same as for a stroke
There are 2 main types of stroke
What are they?
Ischemic & hemorrhagic
? stroke
Results from a rupture of a vessel within the brain tissue or within the subarachnoid space
Hemorrhagic
? stroke
Occurs when the blood to a part of the brain is interrupted or totally occluded
Result from cerebrovascular obstruction by thrombosis or emboli
Ultimate survival of brain tissue depends upon the length of time it is deprived plus the amt of brain tissue affected
May be referred to as thrombotic or embolic stroke
Ischemic
___ stroke
Hemorrhagic
___ stroke
Embolic
___ stroke
Thrombotic
Major types of stroke
Thrombotic / Embolic / Hemorrhagic
Ischemic: ____
- Forms outside the brain - traveling from another area
> Freq sites: bifurcations of vessels particularly MCA - Cardiac dz - rheumatic heart dz, heart valve dz, >MI [cardiogenic embolic]
> Left heart chambers; afib
> Carotid arteries - Younger
- Sudden & immediate
- Maximum deficits
Embolism
Ischemic: ____
- Atherosclerosis
- Platelet aggregation
- Stenosis
- Occlusion of large cerebral vessel
- Hypertensive
- Clinical manifestation progresses gradually
- Sleeping or upon awakening
- Can present as a TIA (stroke-in-evolution)
Thrombosis
Hemorrhagic
Can be intracerebral (ICH) in the brain tissue or subarachnoid (SAH) bleed b/t brain layers pia mater & arachnoid
- subarachnoid: rebleeding before surgery (!)
! Occurs when a cerebral blood vessel ruptures
- Rupture of blood vessel
- Cause: HTN, aneurysm, trauma, AVM, anticoag, blood dyscrasias, drug abuse
- Sudden, quick, or gradual - caused by HTN
- Focal deficits: severe
- Permanent deficits
! Often fatal
Intracranial hemorrhage
- HA (worst of one’s life)
- Meningeal irritation; neck pain - nuchal rigidity
- Light intolerance
- N/V
- Hemiplegia
- Dec LOC
- Seizures
Hemorrhagic Stroke
! Massive hypertensive hemorrhage rupturing into a lateral ventricle of the brain