Ischemic Stroke Flashcards
What is the difference between a stroke and a TIA?
TIA- the symptoms last less than 24 hours
What are the most likely cause of large vessel occlusion?
thromboembolism from heart or aortic arch. Atherosclerotic rupture in the internal carotid- may even break off an embolus
What are some of the causes of small vessel occlusion
Lose penetrating arteries- lipohyalinosis, small vessel thrombosis, dissection of artery causing occlusion or creating embolus to the brain, vasospasm frum drug, infection, HTN, irritation of the artery
What are the symptoms of large vessel stroke?
Multiple systems affected
What are the symptoms of large vessel stroke?
Single system affected- hemiparesis or hemisensory loss
What does occlusion of MCA cause?
hemiparesis, hemsensory deficit, hemianopsia, aphasia (dominant)
What are treatable risk factors for ischemic stroke?
Hypertension Lipid Disorders Homocysteine Elevations (?) Smoking Obesity Diabetes
What is the benefit of statins in preventing stroke?
cause release of NO
What treatment can be used for insulin resistance (HOMA test)?
Pioglitazone
What are some less common mechanisms of stroke?
fibromuscular dysplasia, moya-moya disease (overly thickened vessels), spontaneous arterial dissection
What are hematological issues that cause stroke in young patients?
Protein C, Protein S, Antithrombin, Factor V Leiden, Prothrombin Gene, etc...all venous risks with unclear arterial risk SSA, very tiny risk, if any, for SST Malignancies (Noble still waiting…) Oral Contraceptives, Post Partum Anti-Phospholipid Antibody Syndrome
What are some other factors that contribute to stroke?
Alcohol Abuse (not use...) Stimulant Abuse (use?) Physical Inactivity/Obesity Congenital Hearts PFO/ASD/VSD Acquired Cardiacs: CHF, Valvular, A-Fib, Myxoma.....
What is the main cause of CNS vasculitis?
Varicella Zoster virus, also meningitis
When are you at highest risk for superior sagittal thrombosis?
day 3 postpartum
What are the treatments for stroke
Add any Anti-platelet agent ASA Clopidogrel/Ticlopidine/Prasugrel ASA/Dipyridamole ASA/Clopidogrel Or, Add an Anticoagulant A-Fib Mechanical Valves CHF? Short Term Thrombus in artery, Dissection
What do you do for acute treatment?
TPA up to 4.5 hours and IA up to 6 hours
Recognize the general presentation of a large vessel or small vessel ischemic stroke and Transient Ischemic Attack (TIA).
large vessel ischemia due to the partial or complete occlusion of a major artery leads to multiple affected systems
small vessel ischemia create lacunar infarcts to due to occlusion of the small penetrating vessels that arise from large arteries deep into the brain, leading to isolated motor or sensory loss on one side.
Transient Ischemic Attacks are neurological deficits that have completely resolved by 24 hours.
Discuss the non-atherosclerotic causes of stroke in a young patient
Vasculopathies:
- Fibromuscular Dystrophy: usually in women in their 30s or 40s. Hypertrophy of the smooth muscle in the media of vessels. Typically involves renal artery, but may also include vertebral and carotid. Also associated with arterial dissection and intracranial saccular aneurysms
- Moya-Moya: children, women in their 30s or 40s, and elderly (especially Asian and African-American) get focal occlusion in the middle cerebral artery due to intimal hyperplasia. In elderly it can be HTN or hyperplasia. Also associated with arterial dissection and saccular aneurysm in young people. EBV has been associated with Moya-Moya
- Spontaneous Arterial Dissection: Typically well tolerated, however emboli can form, break off, and occlude distal arteries. Therapy is with anticoagulation until the dissection heals, although intra-arterial stenting or surgery can have a role.
Hematological Disorders
- Deficiencies of protein C, Protein S, or Antithrombin
- Factor V Leiden and Prothrombin
- Thrombosis from PFO/ASD
- Malignancies cause hypercoagulable state
- Sickle Cell Anemia
- Hyperviscosity states: Protein, elevated hematocrit (60%), thrombocytosis (1,000,000), etc. can generate slowness of flow beyond the pump & pipes ability to compensate
- OCP
- Antiphospholipid antibodies
Inflammatory Mechanisms:
- Vasculitis- In the CNS, may be associated with VZV
- Migraine- can cause stroke through vasospasm or increased platelet aggregation
Venous Infaction: Usually due to trauma. Can also be from dehydration, CNS infection, hypercoagulable states. Think of post-partum sagittal sinus thrombosis.
Vasospasm
Discuss the basic principles of emergency treatment of ischemic stroke
Treat HTN only if very severe, Rehydrate, TPA within 3 or 4.5 hours, give glucose only if hypoglycemic
Discuss how to modify metabolic, lifestyle, and structural risk factors for stroke.
“good health” approach (sleep, eat healthy, exercise, fitness, low stress, high happiness) as well as specific dietary, vitamin and medication therapies where needed.
The single agents that reduce the long term risk of recurrent ischemic stroke are aspirin, Thienopyridines (Clopidogrel, Prasurgrel, Ticlopidine) and Anticoagulants. Endarterectomy was highly beneficial in symptomatic
patients with high grade (70-90%) stenosis.
Discuss the importance of mechanism of stroke in both resuscitation and prevention
Ischemic stroke can be resuscitated with thrombolytic agents (i.e. Tissue Plasminogen Activator or TPA) given IV or by IA catheter as long as you get this done within 4.5
hours or perhaps longer in highly selected cases. Keeping fluids up, maximizing cardiac output, and resisting the temptation to lower blood pressure (i.e. stepping on the fire hose) help, too. Research into the use of mechanical IA techniques (grab the embolus, fracture it, angioplasty, stenting, etc.), hypothermia, and neuro-protective drugs continues.
