10-25 Stroke Flashcards
Stroke Warning Signs
—Sudden weakness or numbness of the face,
arm or leg, especially on one side of the body
—Sudden confusion, trouble speaking or understanding
—Sudden trouble seeing in one or both eyes
—Sudden trouble walking, dizziness, loss of
balance or coordination
—Sudden, severe headache with no known
cause
Stroke Mimics
Seizures Brain tumors Migraine Hysteria Inner ear disorders (vestibulitis) Hypoglycemia Hypotension/severe hypertension Multiple sclerosis
DWI vs PWI
diffusion weighted vs. perfusion weighted
—diffusion weighted shows infarction
—PWI shows penumbra
possible targets of neuroprotective therapy
Prevention of early ischemic injury
Prevention of reperfusion injury
Prevention apoptosis and promotion of repair,
regeneration
**all have failed so far, but ETHANOL maybe!
Time limit for tPA
3 hrs
Intra-arterial thrombolysis Time window
6 hrs
Mechanical devices to remove clot Time window
8 hrs
Prevention of Stroke (In order of effectiveness?)
¡¡¡Warfarin for atrial fibrillation!!!
Carotid endarterctomy for symptomatic dz
Smoking cessation
Antihypertensive therapy if BP elevated
Statins if cholesterol elevated
Aspirin
Risk Score for Stroke?
Modified Framingham Stroke Risk
- Age
- un-tx’d SBP
- Tx’d SBP
- H/o DM
- Smoking
- CVD
- A. fib
- LVH on EKG
Causes of Hemorrhagic Stroke
A) Subarachnoid hemorrhage 1. Aneurysms (berry, e.g.) 2. Trauma (more commonly here) 3. Drugs B) Intracerebral hemorrhage 1. Small artery disease/Hypertension (MOST COMMON HEM STROKE) 2. Anticoagulants (esp subdural; iatrogenic or natural) 3. Trauma 4. Bleeding disorders 5. Tumors 6. Aneurysms (Berry)/AVMs
Prevention of Hemorrhagic Stroke
Prevent inappropriate anticoagulation
Control BP and smoking
Prevent head injuries and illicit drug use
Important Differences between MI and CVA
a. Painful vs. no pain and often poor awareness b. Public recognizes symptoms and need for action vs poor recognition of symptoms and need for action
c. Bleeding into the heart doesn’t occur vs brain hemorrhage is common
d. Diagnosis is easy using EKG and cardiac enzymes vs there is no easily available “stroke-o-gram”
e. Cause is in-situ plaque rupture vs causes are numerous!
transient monocular blindness (TMB; amaurosis fugax)
dimunition or loss of vision in one eye that:
—comes on quickly (secs)
—lasts 1-5min
—resolves over 12-20 mins
SWENSON: “Acute development of neurologic symptoms due to ischemia that completely resolve within 24 hours.”
transient ischemic attack
—resolves fully w/o no residual sx after 1 hr
—tx goal: prevent full blown stroke
—work-up: CBC, PT, aPTT, ESR syph, glucose, EKG, DWI or CT; consider angio or doppler of carotids
—tx: don’t lower BP; heparin, ASA/clopidogrel, statins; carotid endarterectomy > stenting
do terms on website
http://www.dartmouth.edu/~dons/part_3/chapter_27.html
How common is stroke?
Over 750,000 people have strokes per year (it is the #3 killer).
What % of stroke = ischemic?
~80%
What are potential sites of emboli to the cerebral circulation?
arteries, heart and aorta
—major % from plaques in the aorta, carotids or vertebrobasilar arteries
—Cardiac sources include a.fib, severe valvular dz (incl endocarditis), CHF (or ventricular dyskinesia, with blood pooling + clotting), or recent MI
—Emboli may also pass from the venous side to the arteries via right to left shunts (such as a patent foramen ovale)
Risk factors for small vessel dz + TX
—Lipohyalinosis is the most common pathology and HTN, DM and age are main risk factors.
—Vasculitis and stimulant abuse are other causes.
—If vasculitis/substance abuse — tx that, otherwise anti-platelets. no real definitive therapy
Lipohyalinosis
Lipohyalinosis is a small-vessel disease in the brain characterised by vessel wall thickening and a resultant reduction in luminal diameter
Risk Factors for large vessel dz + tx
—large vessel disease = atherosclerosis
—RFs incl: HTN, hyperlipidemia, fam Hx, age, smoking and homocystinemia.
—Tx = platelet antagonists, folic acid (helps decrease homocysteine), and carotid endarterectomy (if there is high grade carotid stenosis)
What are some causes of stroke due to increased viscosity of the blood?
—severe dehydration —dysproteinemias —polycythemia —thrombocytosis —leukocytosis (rarely and with severe elevations such as leukemia).
Major risk factors for stroke
hypertension, age, cardiac disease, heredity, smoking, DM, hyperlipidemia, obesity, homocysteinemia (remember folate/B12/B6), hyperviscosity, alcohol excess, hypercoaguable states, sedentary lifestyle.
—OCPs may in young women, particularly if they are a smoker, with migraine. The stroke may be due to venous thrombosis of the sagittal sinus.
What major factors prevent the development of stroke with occlusion of cerebral blood vessels?
collateral circ
What are the stages of recovery from stroke?
—Recovery from stroke may be complete or incomplete. Some tissue is functionally damaged but not killed (ischemic penumbra) and this area may recover early on.
—There is some redundancy of function and other areas can take over. There is some resolution of cytotoxic edema (not treatable by steroids).
—There is some plasticity, even in the adult brain and this can be encouraged by rehabilitation. While there may be new neurons produced, we are not sure whether they are functionally important.
—Later recovery involved compensation, when other methods of recovery fail. Compensation requires recognition of deficits and the ability to incorporate strategies to get around the deficits.
How can ischemic stroke result in death?
—cytotoxic edema, with swelling and ultimate brain herniation (this swelling can not be treated with steroids although osmotic agents may temporarily help)
—subsequent hemorrhage due to weakening of the blood vessels in the damaged tissue.
—complications of general debility (pneumonia, pulmonary emboli, poor nutrition, decubiti).
What are the therapeutic options for a stroke in progress?
Aspirin and oxygen may be helpful. Do not lower blood pressure excessively.
—Thrombolysis may be effective in treating patients in the very acute stage (less than 3 hours from the moment of onset).
—Cytoprotection under investigation
Causes of stroke chez les jeunes
hypercoagulability or hyperviscosity, arterial dissection, cardiac abnormalities or paradoxical embolism (through right to left shunt).
What major factors prevent the development of stroke with occlusion of cerebral blood vessels?
collateral circ
