Stroke Flashcards
Cerebrovascular disorder
an umbrella term that refers to a functional abnormality of the CNS that occurs when the blood supply to the brain is disrupted.
Stroke is the primary cerebrovascular disorder.
Types of Strokes
- Ischemic:
- thrombotic
- embolic
- decreased CPP
- lacunar
- Transient Ischemic Attach (TIA)
- Hemorrhagic
- cerebral aneurysms
- arteriovenous
Stroke Statistics
-28% of ppl who suffer a stroke are under age 65
-every 3-4 minutes, someone dies of a stroke
-among ppl 45-64 yrs old, 8-12% of ischemic strokes and 37 are 38% of hemorrhagic strokes result in death w/in 30 days
-sick cell disease is the most important cause of ischemic stroke among African-American children
-w/in a yr, up to 25% of ppl who have had a TIA will die. This % is higher among ppl 65 and older.
Ischemic Etiologies
- atherosclerosis
-cardiogenic emboli
-idiopathic: up to 30% have unknown cause. Other causes = arteritis vasospams, inflammation, coagulation disorders, endothelial dysfunction, prescribed drugs, street drugs
-global hypoperfusion
-lacunar
-other causes
Factors Affecting Stroke Outcomes
-rate of onset & duration
-collateral circulation
-health of systemic circulation
-hematologic factors
-temperature
-glucose metabolism
Classification of Non-Hemorrhagic Strokes
- transient ischemic attack (TIA)
-reversible ischemic neurologic deficit (RIND)
-stroke in evolution
-stablished stroke
Hemorrhagic Etiologies
-arteriovenous malformation
-uncontrolled HTN
-cerebral hemorrhage
BE FAST (how to spot a stroke)
B: balance (sudden loss of balance or coordination?)
E: eyes (double vision or unable to see out of one eye?)
F: face (drooping face? ask pt to smile)
A: arms (one arm drift downward? raise both arms)
S: speech (slurring speech?)
T: time (call 911)
Normal BP
< 120 & <80
Prehypertension
120-139 and 80-89
Stage 1 hypertension
140-159 and 90-99
Stage 2 hypertension
> 160 and >100
Saccular Aneurysm (Types of Cerebral Aneurysms)
-refer to any aneurysm w/ a saccular out pouching including berry aneurysms
-saccular aneurysms are the most common form of cerebral aneurysm
Fusiform Aneurysm (Types of Cerebral Aneurysms)
-describes an aneurysm w/out a stem often associated with atherosclerosis
Circle of Willis
Connects the anterior and posterior blood supply to the brain, creating a collateral type of circulation so that different sections of the brain are not dependent on just once vascular source
Internal carotids supply anterior portions of the brain. Vertebral arteries supply posterior portions.
Lacunar Stroke
-Most strokes damage brain tissue in the outer part of the brain or cortex. Strokes that injure deeper structures underneath the cortex are called lacunar strokes.
A lacunar stroke occurs when:
one of the arteries that provides blood to the brain’s deep structures is blocked.
-unlike most arteries which gradually taper to a smaller size, the arteries of a lacunar stroke branch directly off a large, high pressure main artery
-HTN can lead to lacunar strokes because of strong pulsitile pressures that can dislodge thrombi or plaque in the main artery, causing blockage of blood flow to a smaller arterial offshoot.
Grade I
minimal bleed: asymptomatic or minimal headache, slight nuchal rigidity
Grade II
mild bleed: moderate to severe headache, nuchal rigidity, minimal neurologic deficits
Grade III
moderate bleed: drowsiness, confusion, mild focal neurologic deficits
Grade IV
moderate to severe bleed: stupor, moderate to severe hemiparesis, early decerebrate posturing
Grade V
severe bleed: deep coma, decerebrate rigidity, disruption of vegetative functions
Arteriovenous Malformation
AVM: an abnormal connection between arteries and veins in the brain that is present at birth (congenital)
-cause is unknown, but main risk is intracranial hemorrhage
Arteriovenous Malformation S/S:
-loss of consciousness, sudden and severe headache, nausea, vomiting, incontinence, and blurred vision
-a stiff neck can occur as the result of increased pressure w/in the skull and irritation of the meninges
Asessment
-assure adequate airway
-monitor vital signs
-conduct general assessment
-evidence of trauma to head or neck
-identification
-conduct neuro exams
-LOC
-presence of seizure activity
-glasgow coma scale / NIHSS
-Pupils: size, equality, reactivity
-individual limb movements
RN Responsibilites
-uncontrolled HTN leads to increased ICP which can increase the risk for death
Factors that Mimic Stroke
-postictal states
-systemic infections
-tumors
-toxic-metabolic disturbances
-decreased LOC
Diagnostics
-CT of the brain w/out contrast
-electrocardiogram
-chest x-ray
-hematologic studies (CBC, Plt Count, prothrombin time, partial thromboplastin time)
-serum electrolytes
-blood glucose
-renal and hepatic chemical analyses
-national institutes of health scale score (NIHSS)
For Carotid Endarterectomy
watch for s/s of bleeding; measure circumference of neck; CCBs for vasospams
Triple H Therapy
is a medical tx used to prevent vasospasm after aneurysmal subarachoid hemorrhage
Hypertension
Hypervolemia
Hemodilution
Thrombolytic Therapy has a treatment window of:
3 hours after the onset of a stroke
Ischemic Stroke definition
aka brain attack - a sudden loss of function resulting from disruption of the blood supply to a part of the brain.
Urgent health care issue.
TIA
a neurologic deficit that completely resolves in 24 hrs (most last less than 1 hr). Manifested by sudden loss of motor, sensory, or visual function.
-temporary ischemia (impairment of blood flow) to a specific region of the brain
