Two types of stroke:
Ischemic & hemorrhagic
Inadequate blood flow to the brain; occlusion of an artery. 80% of all strokes are ischemic.
Ischemic strokes are divided into 2 subcategories:
Thrombotic & Embolotic
Plaque buildup (thrombosis) narrows artery; injury to arterial wall near plaques results in formation of blood clot which further blocks the artery. Common cause: HTN. 60% of strokes are thrombotic.
Embolus (floating plaque or other solid substance in bloodstream) lodges in a cerebral artery resulting in infarction and edema. 24% of strokes are embolotic.
Small artery occlusion, infarction of brain tissue. Cavity formation at site of cell death.
Rupture of artery with bleeding into the brain tissue. 15% of strokes are hemorrhagic. Described as "worst headache of my life."
The 3 major types of stroke:
The most important diagnostic tool to evaluate for stroke is:
- CT without contrast
- - Obtain within 25 minutes of arrival at ER
- - Radiologist to read within 45 minutes of arrival
- - Indicates size & location of lesion
- - Differentiates between ischemic and hemorrhagic stroke
Ischemic stroke: Fibrinolytic therapy with tissue plasminogen activator (tPA) is indicated when:
- - Ischemic stroke is <3 hours old
- - CT appears normal with no signs of hemorrhage anywhere in body
- - No bleeding history or head trauma in past 3 months
- - No major surgery within 14 days
CT Angiography (CTA) detects:
Intracranial and extracranial vascular occlusive disease. It is the "gold standard" for imaging the carotid arteries.
Extent of brain injury (has greater specificity than CT).
Risk factors for stroke:
- Diabetes mellitus
- High serum lipids
- Cardiac dysfunction
On-scene assessment test for stroke: FAST
- - Ask person to smile.
- - Does one side of face droop?
- - Ask person to raise both arms; can s/he?
- - Does one arm drift downward?
- - Ask person to repeat a simple sentence.
- - Are words slurred?
- - Can s/he repeat sentence correctly?
- - If person shows any of these symptoms, call 911.
- - Time is Tissue!
Transient ischemic attack (TIA):
3) Classic sign.
- 1) Temporary loss of brain function d/t ischemia.
- 2) Usually resolves within 3 hours (15 min. to <24 hours).
- 3) Classic sign is vision loss in one eye with no pain or warning.
Immediate assessment of a stroke patient at the ER includes:
- - Assess ABCs, vitals
- - Provide O2 via NC
- - IV access
- - Obtain blood sugar sample (hypoglycemia can mimic stroke)
- - 12-lead EKG
- - Neuro screening assessment (Glascow)
- - Alert stroke team: Neurologist, radiologist, CT tech
- Most important: Check onset of symptoms!
- (Time is Tissue)
Ongoing monitoring of a stroke patient includes:
- - Vital signs
- - Neurologic status & LOC (Glascow coma scale)
- - Motor & sensory function
- - Pupil size & reactivity
- - SaO2
- - Cardiac rhythm
The incidence of ischemic stroke in patients with TIAs and other risk factors is reduced with the administration of:
Daily low-dose aspirin
The medication used to treat a subarachnoid hemorrhage is:
Nimodipine, a calcium channel blocker, inhibits vasospasm of a hemorrhaging artery.
To reduce the risk of stroke-induced seizures, this medication is administered prophylactically:
A right-sided brain stroke with homonymous hemianopsia results in vision loss of the ______ (right/left) field.
- Homonymous hemianopsia results in visual field loss of the field contralateral to the stroke location.