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26 Cards in this Set
- Front
- Back
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Every 24 hours the brain requires...
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-150g glucose
-73 liters of O2 -no storage capacity |
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Regulation of CBF
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-occurs at the level of the arterioles
-dilate in response to hypotension -constrict in response to hypertension |
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Stroke
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-"brain attack"
-caused by an interruption of blood flow to the brain -brain cells in the immediate vicinity die within min-hrs- INFARCT ZONE |
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Penumbra Zone
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-Ischemic cascade is a chain reaction that endangers brain cells in a larger, surrounding area of brain tissue for which the blood supply is compromised but not completely cut off
-pharmacotherapy most helpful here |
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Stroke symptoms
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1. Sudden numbness or weakness of face, arm or leg, esp on 1 side of the body
2. Sudden confusion, trouble speaking or understanding 3. Sudden trouble walking, dizziness, loss of balance or coordination 4. Sudden severe HA w/ no known cause 5. Sudden trouble seeing in 1 or both eyes |
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less common stroke sx
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-SUDDEN nausea, fever, vomiting
-brief loss of consciousness or period of decreased consciousness (fainting, confusion, convulsions or coma) |
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stroke types
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1. ischemic- 70%
-Hypoperfusion -Emoblism -thrombosis 2. hemorrhagic- 30% |
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Hypoperfusion
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-watershed/borderzone ischemia
-carotid territory (frontal areas of brain, parts of retina) -vertebro-basilar (occipital lobe) -penetrating vessels |
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Testing for strokes
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-CT scans in acute setting
-then MRI later on (more sensitive days after) |
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Embolism
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-occlusion of a cerebral blood vessel by a small piece of blood clot, tumor, fat, air, or clump of bacteria
-emboli may partially or totally occlude a cerebral vessel (either way get sx) -emboli to brain are frequently multiple -assoc with infarcts in lungs, spleen, kidney |
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Embolic sources
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1. Carotid artery*- plaque, dissection (listen for bruits)
2. Vertebral artery- plaque, dissection 3. Aorta- plaqu, dissection 4. Heart- atrial fib*, valvular vegetations or calcifications, cardiomyopathy, MI, tumor, PFO/ASA, sick sinus syndrome |
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Thrombosis causes
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-atherosclerosis
-hypercoagulable state (blood becomes too thick because of an abnormality in the clotting cascade) |
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Atherosclerosis
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-clotting at the site of an ulcerated plaque in the vessel wall
-clot propagates until it occludes the lumen |
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Stroke sequelae
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1. Edema (can compress other parts of the brain that may have not been affected by the stroke)
2. Seizure 3. Hemorrhagic transformation |
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Stroke Complications
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1. DVT/ PE
2. Aspiration pneumonia 3. Stress Ulceration 4. Fall 5. Pressure sores 6. UTI 7. Spasticity/contractures |
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Intracerebral hemorrhage
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-bleeding into the brain results from rupture of one of the cerebral vessels
-In many cases, hemorrhage derives from a ruptured arteriosclerotic vessel. -ICH patients experience a higher mortality and suffer more severe deficits than patients with any other stroke subtype. |
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Etiology of hemorrhagic strokes
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1. HTN
2. Cerebral amyloid angiopathy (detected in autopsy) 3. Small vascular malformations 4. Sympathicomimetic drugs 5. Alcohol 6. Intracranial tumors 7. Anticoagulation** 8. Fibrinolytic agents 9. Vasculitis/Vascuopathy |
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Peri-lesion edema
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-edema contributes to neurologic deterioration after ICH
-disruption of the BBB leads to vasogenic edema -Vasogenic edema appears as a hypodensity on CT and as a hyperintensity on T2-weighted MR images |
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Subarachnoid hemorrhage
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-most common cause is a ruptures saccular aneurysm (berry aneurysm)
-AVM -Trauma -get sudden onset HA "worst HA of their life" -CT scan |
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Treatment options for strokes
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1. Plasminogen activators* (clot busting)
2. Anticoagulation 3. Anti-plt therapy 4. Interventional modalities 5. Surgical/aneurysmal clipping 6. Hemicraniectomy 7. Neuro-protective agents 8. Statins (for cholesterol) 9. ACE-inhibitors/ARB's |
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tPA
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-short half life
-goal: lysis of obliterating thrombus with reestablishment of CBF -fibrin-specific -time frame to use: 4.5 hrs -for acute stroke its use is in favor of treated pts but is assoc. with an excess of sympotatic ICH |
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Benefit and Risks of IV tPA for stroke
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Benefit: neurologically nml at 3 months
-risk of symptomatic ICH= 6.4% |
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anti-coagulation in acute stroke
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-Urgent routine anti-coagulation with goal of improving neurological outcome or preventing early recurrence not recommended.
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Dipyridamole
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-blocks re-uptake of adenosine formed from precursors released by red blood cells, providing feedback inhibition of platelet aggregation.
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most people with ischemic strokes that have an identifiable cause...
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...treat with coumadin!
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treatment with statins
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-studies show that they have reduced stroke in women by 40%
-also have an anti-inflammatory effect |
