A. Ischemic Stroke
1. Results from blockage of a cerebral artery, leading to decreased blood flow. 2. Cerebral blood arteries dilate and constrict due a process called cerebral autoregulation. 3. This process is affected by stroke
4. One possible ischemic stroke occurs due to blockage of an intracranial vessel due to an embolus from a distant area (i.e. cardiogenic embolus), 5. Another possible ischemic stroke occurs due to in situ thrombosis of an intracranial vessel, usually one of the smaller penetrating arteries (usually due to carotid plaque on the arteries). 6. Another possible ischemic stroke is due to hypoperfusion caused by flow-limiting stenosis of a major extracranial artery. 7. If blood cannot get to the brain, oxygen and nutrients cannot get there either. 8. This leads to depletion of ATP and accumulation of extracellular potassium, intracellular sodium and water, leading to cell swelling and lysis. 9. Intracellular calcium increase leads to the release of fatty acids from cell membranes. 10. The release of amino acids such as glutamate and aspartate then leads to release of free radicals, damaging brain cell.s 11. All this occurs within 2-3 hours of clot formation.
1. Since stroke can mimic other conditions (seizure, migraine, with aura, brain tumor, EtOH withdrawal) it is crucial to obtain a proper diagnosis. 2. Patient history.
a. Time of Onset; the last time the patient was awake and “normal i.e. last time they entered the kitchen or bathroom. Can look at prestroke cell phone or TV use for clues. EMS personnel can be helpful here. b. Any transient neurological effects? If time of onset is reset. c. Circumstances surrounding Sx onset.
d. Risk factors (HTN, DM, hyperlipidemia, etc)
e. Medical Hx (seizure or headache disorder, infection, trauma, pregnancy) 3. Physical exam
b. Vital signs
c. Head and face exam (can rule out seizure)
d. Ausculation of chest (can rule out...
Please join StudyMode to read the full document