9. Rorabaugh - Stroke Flashcards
What is the definition of transient ischemic attack (TIA)?
Acute episode of focal cerebral ischemia that lasts form a few minutes to up to 24 hours (usually 5-10 minutes)
Does the brain have the ability to store glycogen?
No
What is the only fuel source for the brain?
Glucose is the only fuel source
How is blood flow regulated in the brain?
Regulated based on blood volume
What is the constant rate of blood flow in the brain?
50 mL/min/100 grams tissue
What is autoregulation in the brain?
Cerebral blood flow remains constant over a wide range of systemic blood flow pressures
What does the brain vessels do when systemic BP is high?
Cerebral vessels will constrict, preventing excessive blood flow
What will the brain vessels do when systemic BP is low?
The vessels will dilate to maintain flow
What is the definition of global ischemia?
Result of generalized reduction of cerebral perfusion, the entire brain is affected
What is the definition of focal cerebral ischemia?
Result of reduction of blood flow to a localized area of the brain, just a single region is impacted
What happens to neurons when the brain experiences ischemia?
- Decrease in ATP to pump Na out and K in
- Causes deloplarization, and VG Ca channels open
- Ca flows into the cell, but cannot leave, causing NT release
- NT release cause a increase in energy deficit
- End result: kills additional neurons
What is the major artery affected from a stroke?
Middle cerebral artery
What are the nonmodifiable risk factors of stroke?
Age, male, race, heredity
What are a few modifiable risk factors for stroke?
HTN, TIA, Afib, DM, smoking, obesity
What are the two main types of stroke?
Hemorrhagic and Ischemic
What happens during a hemorrhagic stroke?
Excessive bleeding occurs inside of the brain or around brain tissue. The brain is lacking perfusion because blood is leaking into tissues.
What happens during ischemic stroke?
Cerebral BVs are blocked, blood cannot flow, and there is no perfusion beyond blockage
What are 5 causes of ischemic stroke?
- Atherosclerosis - main cause
- Thrombosis - usually originating from the left heart
- Extracranial embolism
- Arteritis secondary to infection - syphillis/TB
- Dissection of carotid arteries
What is a lacunar infarction?
Atherothrombotic occlusion of a small artery that penetrates deep into the brain. A pool of fluid less then 15mm in diameters
What are 3 characteristic of a TIA?
- No neurological abnormalities btwn attacks
- Caused by micro emboli temporarily occludin arteries
- Is a warning sign of impending stroke
When are most TIAs followed by a stroke?
Usually w/in the same day or w/in 24-48 hrs after TIA
What are the risk factors for stroke following a TIA (ABCD scores)?
- Age
- BP
- Clinical symptoms
- Duration of symptom
- ABCD2 - diabetes
What are the causes for a hemorrhagic stroke?
HTN, rupture of cerebral aneurysm or angioma, and trauma
What are the symptoms of hemorrhagic stroke?
- Might loose consciousness
- Headache, dizziness, nausea
- Rapid onset
What is a subarachnoid hemorrhage stroke?
Bleeding into the subarachnoid space, increasing cerebralspinal fluid volume and intracranial pressure
What are they symptoms of subarachnoid hemorrhage?
- Severe headache
- Vomiting
- Convulsions
- Loss of consciousness
What are the causes of a subarachnoid hemorrhage?
- Trauma
- Ruptured aneurysm
- Bleeding from intervertebral hemorrhage
What is the main treatment of ischemic stroke?
Restore blood flow, usually by tPA (tissue plasminogen activator)
What are the 3 inclusion criteria for tPA treatment?
- Diagnosis of ischemic stroke
- Onset of symptoms less than 3 hours from treatment
- 18yrs or older
What are some exclusion criteria for tPA treatment?
Head trauma, prior strokes, symptoms suggesting hemorrhage, blood glucose
What percentage of all stroke patients receive tPA? (All and w/in 2 hrs)
All: 7%
W/in 2 hrs: 75%
What are some other treatments of ischemic stroke?
Basic life support (stabilize pt: BP, glucose, O2)
Treatment of acute neurological complications
What are the two treatments to prevent an acute secondary stroke?
- Carotid endarterectomy
2. Warfarin
What are the treatments for long term prevention of a second stroke?
Coumadin, aspirin, anti-platelet drugs, statins, HTN drugs
What is the treatment for a hemorrhagic stroke?
- Manage BP
- Manage intracranial pressure
- Prevent recurrent hemorrhage
- Surgery if close to surface of brain
What is the definition of stroke?
Disrupt the blood supply to a region of the brain that causes neurological impairment
