15. Ischemic Diagnosis and Management Flashcards
Ischemic stroke definition
Cerebral ischemia >24hrs or
Transient ischemic attack
Complete recovery of transient ischemia with transiet episode of neurologic dysfunction. No evidence of infarction usually through MRI
Cerebrovascular disease is the _____ leading cause of death in the US
CVD is 4th lading cause of death
Which type of strokes are more common: Ischemic or hemorrhagic?
Ischemic
Go through the circle of willis
Vertebral arteries give off anterior and posterior spinal arteries, and POSTERIOR INFERIOR CEREBELLAR A (PICA)
Vertebral a. combine to form the basilar a
Basilar gives off ANTERIOR INFERIOR CEREBELLAR A (AICA), pontine arteries, and SUPERIOR CEREBELLAR A.
Basilar a bifurcates into POSTERIOR CEREBRAL A (PCA)
PCA joins anterior circulation via POSTERIOR COMMUNICATING A
INTERNAL CAROTID bifurcates into ANTERIOR CEREBRAL A AND MIDDLE CEREBRAL A (ACA, MCA), (Internal carotid also gives off the opthalmic a and anterior choroidal a)
Anterior cerebral artery infarct
Supplies the middle of hemispheres= hemiparesis and hemiparalysis of contralateral side –> legs, maybe arms, SPARES FACE
Middle cerebral artery infarct
Supplies the lateral hemispheres and temporal regions = hemiparesis and hemiparalysis of contralateral side –> face, arms, spares legs usually
If on dominant hemisphere –> aphasia (speech and language)
Posterior cerebral artery infarct
Supplies the visual cortex (occipital lobe) = visual deficits –> contralateral homonymous hemianopia
If dominant hemisphere involved –> receptive aphasia (fluent aphasia, patients can understand language but cannot express themselves aka sentences they say don’t make sense)
Basilar artery infarct
Supplies pons, midbrain, medulla = dizzziness, diplopia, dysarthria (unclear speech), Locked-in Syndrome (person has retained consciousness but are paralyzed except for vertical eye moement), coma and death
Carotid TIAs have two forms. What are they, and describe them.
Retinal: carotids supply ophthalmic artery, so emboli can travel into it and impair retinal circulation –> transient blindness in right eye
Hemispheric ischemia: Carotid supplies entire hemisphere of brain; transient weakness or numbness of contralateral side
What would a vertebral-basilar TIA present as?
Transient dysfunction of brainstem –> slurred speech, difficulty swallowing, altered consciousness
Basilar artery also supplies occipital lobe –> visual defects
Can TIAs progress to strokes?
YES, TIAs can lead to strokes
How do you assess for the risk of TIA progressing to a stroke?
Use the ABCD2 criteria:
Age: > 60
BP: > 140 sys, > 90dia
Clinical features (2pts): weakness, speech impairment
Duration: > 60mins = 2pts, 10-59mins = 1pt
Diabetes
If pts > 3, ADMIT THE PATIENT
Tx for TIA
Anticoagulants: Heparin and coumadin
Profess trial: Plavix (clopidogrel) is better; reduced hemorrhage risk
What is important about taking ASA + Plavix?
ASA + Plavix is for short-term use: 90 day max in high risk patients (much higher risk of bleeding afterwards)
What anticoagulants may be used in addition to warfarin with a cardioembolic TIA?
Dabigatran, rivaroxaban, apixaban
What are the surgical treatment(s) for TIA? Which is better?
Carotid endarterectomy, carotid stenting
Endarterectomy better because it has a lower peri-operative stroke risk than carotid stenting
When do you use surgical methods vs medical methods for carotid TIAs?
Surgical: >70% stenosis
Medical:
Auscultation of carotid bruits: Why are they not done with assymptomatic people?
They are not done because the chance of a benefit from surgical intervention is lower than chance of harming patient
Still want to listen though because it may tell you about vascular disease elsewhere in the body
Patient comes in and has no neurological deficits and no h/o transient neurologic episodes in the past. Do you listen to carotid bruits?
Yes, but only to see if there may be vascular disease elsewhere in the body. DO NOT use this as a guideline to go for a carotid endarterectomy
In what situation would a watershed infarct occur?
When you have a patient with HTN and you make them acutely hypotensive –> not enough perfusion to the tissues
Ischemia at border zones of vascular territories (MCA - ACA; MCA - PCA)
What is ischemic penumbra
area surounding ischemic tissue –> may be viable due to collateral circulation but can die w/o tx
Acute ischemic stroke - tx
Give anti-HTN meds if systolic BP > 220 (don't want to lower too much because compromise penumbra) Tx hyperglycemia (inc. lactic acid --> inc. ischemia) and hyperthermia (inc. metabolic demands of tissue)
Embolic infarction tx
Anticoagulation
If on warfarin, can give them tPA
