Stroke Lecture 1st Lecture Flashcards
What are the 2 types of stroke?
Ischemic - blood clot blocks flow
Hemorrhagic - Ruptured blood vessels cause leakage
How long do neurologic deficits need to last for it to be classified as a stroke?
24 hours
How long do spontaneous recovery last?
about 3 weeks
Name the 3 etiological categories for a stroke?
Thrombosis - formation of clot within brain
Embolus - bits of matter formed elsewhere that break loose and travel to the brain
Hemorrhage
Where does stroke rank on cause of long-term disability among adults in the US?
1st
Which type of stroke accounts for the most deaths?
Hemorrhagic (37-38%)
Ischemic (8-12%)
Name a major contributor to cerebrovascular disease.
Atherosclerosis
What are the most common sites for atherosclerotic plaques to form?
Origin of common carotid or transition to middle cerebral artery
Main bifurcation of the middle cerebral artery
Junction of the vertebral artery with basilar artery
What are the 3 types of hemorrhagic stroke?
Intracerebral Hemorrhage (rupture of cerebral vessel, usually occurs in small blood vessels) Subarachnoid hemorrhage (Typically from saccular or berry aneurysm affecting large blood vessels, congentinal, linked to chronic hypertension) Arteriovenous Malformation - Congenital defect (tangle of arteries or veins failure to develop (agenesis)
Name some major risk factors for stroke.
Hypertension (BP of 140/90 or higher)
Heart disease
Disorders of heart rhythm
Diabetes Mellitus
Name some other risk factors not major but important to notice for stroke?
High LDL and low HDL
Cardiac disorders (heart valve disease, endocarditis, or CABG increase embolic stroke)
A-Fib (5 fold increase in risk)
End stage renal disease
How does sleep apnea increase the risk of stroke?
Prevents restful sleep and is associated with HTN, arrhythmia, stroke and heart failure
What are some risk factors for women specifically for having a stroke?
Early menopause (before 42)
Use of estrogen plus progestin (increase ischemic stroke)
Pregnancy, birth and the 1st 6 weeks post-artum
Name some modifiable risk factors for stroke prevention?
Smoking
Physical activity
Obesity
Diet
What are the early warning signs for a stroke?
FAST Face drooping Arm Weakness Speech Difficulty Time to Call 911
How soon does a tPA need to be administered for an ischemic stroke?
Within 3 hours of onset of symptoms
What is the ischemic cascade?
- Release of excess neurotransmitters produces progressive disturbance of energy metabolism and anoxic depolarization
- Results in inability of brain cells to produce ATP (energy)
- Followed by excess influx of Ca ions and pump failure of the neuronal membrane
- Excess Ca reacts with intracellular phospholipids to form free radicals
- Ca influx also stimulates the release of NO2 and cytokines, further damaging brain cells
Describe the process of edema forming after ischemic strokes.
- Accumulation of fluids within brain begin within minutes of the insult (reaches maximum by 3-4 days)
- Result of tissue necrosis and widespread rupture of cell membranes with movement of fluid from the blood into brain tissues
- Swelling gradually subsides and disappears by 2-3 weeks
What are some clinical signs of elevating intracranial pressures?
Decreasing level of consciousness Increased HR Irregular respiration Vomiting Unreacting pupils Papilledema (swelling of optic disk, flickering, blurred or double vision)
Describe a TIA
Temporary interruption of blood supply to brain
Symptoms last no longer than 24 hours
No evidence of residual brain damage
Is a precurser to susceptibility for both cerebral infarction and myocardial infarction
Name some other management categories.
Major Stroke - presence of stable, usually severe, impairments
Deteriorating Stroke - Patients whose neurological status deteriorates after admission to the hospital
Young Stroke - Stroke affecting a person younger than 45
How much of a vessel needs to be restricted from atherosclerosis before changes are generally seen?
80% restricted
Name some factors that contribute to the severity and symptoms of a stroke.
Location of the ischemic process
Size of the ischemic area
Nature of the functions of the structures involved
Availability of collateral blood flow (rapid occlusion vs slow occlusion)
What does the anterior cerebral artery supply?
Medial aspect of cerebral hemisphere (frontal and parietal lobes), subcortical structures, including basal ganglia, anterior fornix, and anterior four-fifths of the corpus callosum
What are the most common characteristics of ACA syndrome?
Contralateral hemiparesis and sensory loss with greater involvement of lower extremity than the upper extremity