Ischemic & Hemorrhagic Stroke Flashcards
Fibromuscular Dysplasia (FMD)
Hypertrophy of arterial media causing multiple areas of segmental stenosis; characterstically involves renal, carotid, and/or vertebral arteries and is associated with arterial dissection and intracranial saccular aneurysms
Rare cause of ischemic stroke, primarily affects women in 30s-40s
Moya-Moya
Non-atherosclerotic focal occlusion of the middle cerebral artery due to intimal hyperplasia; also associated with saccular aneurysms and dissection
Rare cause of ischemic stroke, primarily affects women in their 30s-40s
Arterial dissection
Tear in the endothelial lining that allows blood to dissect between the endothelium and the adventitia, within the media; causes “flap” occlusion, and/or may result in emboli which occlude the artery downstream
Hematological disorders associated with ischemic stroke
Protein C/S deficiency Anti-thrombin deficiency Factor V Leiden Malignancies Sickle Cell Anemia Elevated hematocrit (>60%) Thrombocytosis (>1,000,000) Oral contraceptives Antiphospholipid antibodies
Non-modifiable risk factors - Stroke
Age
Gender
Family History
Race?
Structural Risk Factors - Ischemic Stroke
Atrial fibrillation CHF Infectious endocarditis ASD/PFO Cardiac Tumors (Atrial Myxoma) Arterial stenosis Arterial dissection
Modifiable risk factors - Ischeic Stroke
Hypertension Lipid abnormalities - high total/LDL, low HDL Homocysteine elevation Smoking Obesity Physical inactivity Diabetes Alcohol abuse
Use of anti-platelet agents in ischemic stroke
Aspirin - 81mg or 325mg / day
Clopidogrel
Dipyridamole
Use of anticoagulation in ischemic stroke
Warfarin - primary prevention of stroke in patients with atrial fibrillation, mechanical heart valves, previous hx of embolization, HTN, heart failure
Direct thrombin inhibitors (Dabigatran, Rivaroxiban, Apixaban) - stroke prevention in lower risk patients
Heparin / LMWH - IV, used in the acute hospital setting
Indication for carotid endarterectomy
Benefit > risk in patients iwth > 60% carotid stenosis, even if asymptomatic
Subdural hemorrhage - etiology
Occurs between the dura and arachnoid layer; typically from a torn bridging vein between the dura and the cortex; blood collects slowly in a “crescent” shape - may be asymptomatic, enlarging over days to months
Epidural hemorrhage - etiology
Occurs between the skull and dura; typically an arterial bleed caused by laceration of the middle meningeal artery; blood collects in a “lens” shaped hematoma
Subarachnoid hemorrhage - etiology
Occurs underneath the arachnoid layer, next to the brain; may occur secondary to trauma or spontaneously secondary to aneurysm or AVM
Subarachnoid hemorrhage - presentation
Cataclysmic onset, “worst headache of my life”
Sudden death occurs in 1/3 due to acute hydrocephalus or sympathetic surge and cardiac arrhythmia
Cranial Nerve (III) Palsy
Intraparenchymal hemorrhage - etiology and presentation
Blood clots which dissect into the brain, typically in the deep grey matter (putamen, thalamus, pons, cerebellum); associated with chronic hypertension
Presents as mild headache + deficit, progressing over minutes to hours with decreasing level of consciousness; may present as hemiparesis progressing to hemiplegia
Lobar hemorrhages
Atypical, intraparenchymal hemorrhage occurring within the deep white matter; more often caused by AVM, aneurysm, vasculitis, bleeding disorder
Amyloid angiopathy
Recurrent lobar hemorrhages leading to progressive dementia; amyloid deposition is found within the vessels
Arteriovenous malformation (AVM)
Congenital malformation of the resistance arterioles causing high pressure arterial blood to burst into thin-walled capillaries; cause of 2% of all intracranial hemorrhages
Risk factors for aneurysm rupture
Age
Prior hemorrhage
Deep location
*Size doesn’t matter much for rupture risk; matters a lot for treatment
Grading of subarachnoid hemorrhage
Grade 1 - asymptomatic or minimal headache; slight nuchal rigidity
Grade 2 - moderate to severe headache with nuchal rigidity; no neurological deficit other than cranial nerve palsy
Grade 3 - drowsiness, confusion, mild focal deficit
Grade 4 - stupor, moderate to severe hemiparesis
Grade 5 - deep coma, decerebrate posturing
Location of subaracnoid hemorrhage
Anterior communicating artery (40%)
Middle cerebral artery - at carotid bifurcation (20%) or trifurcation branch point (35%)
Basilar artery (4%)
Base of brain bleeds are more likely sporadic in etiology; bleeds in “area of convexity” (cerebral hemispheres, temporal poles) more likely traumatic
Hemorrhagic infarction
Occurs as a result of reperfusion of dead tissue following spontaneous or iatrogenic clot lysis, with leakage of blood from the damaged parenchymal vessel into the surrounding tissue
Usually due to embolism
