Flashcards in Neurology: Strokes Deck (63):
What is the biggest risk factor for stroke?
What are 3 potential genetic risk factors for stroke?
Elevated Homocysteine levels
Factor V mutation (clotting cascade)
What are the two general mechanisms of stroke?
1. Ischemic: atherothrombotic/embolic, cardioembolic, small vessel disease
2. Hemorrhagic: intracerebral, subarachnoid
What is the mechanism of a cerebrovascular atherosclerotic stroke?
Plaque builds up in a cerebral blood vessel (or carotid). The plaque becomes rough and platelets collect along the plaque and eventually form a clot. The clot stenoses the vessel.
What is the #1 risk leading to a cargiogenic embolus-induced stroke, and what is the mechanism?
-this condition does not allow proper emptying of the blood from the atria in the heart. The blood is allowed to pool in the atria and it clots and breaks free forming an embolus. The embolus then travels up to the brain or may even get caught earlier causing the stroke.
Infective endocarditis is another source of an embolus that can lead to a stroke. How is this treated?
Treat the infection.
You do not give clot busters or any anticoagulants due to increased risk of bleeding. Plus the infection will keep causing clots and other heart issues.
What is a sign on CT that a patient has suffered a stroke from a heart issue like atrial fib?
Multiple sites of infarct will be visible in different vascular territories.
Method of treatment for a patient that has a stroke due to an air embolus.
Hyperbaric chamber to relieve pressure in the vessels of the brain.
What is the definition or common presentation of patients with a TIA?
A brief episode of neurological dysfunction caused by focal brain or retinal ischemia with symptoms lasting less than one hour, and without evidence of acute infarction.
Patients present to PCP explaining a focal neuro deficit that "comes and goes".
What are common symptoms of TIA resulting from a carotid stenosis vs. a vertebrobasilar stenosis?
Carotid: unilateral weakness or numbness
-Aphasia if on the dominant hemisphere
-transient monocular vision loss (amaurosis fugax)
VB: bilateral weakness, numbness, vision loss
-brainstem issues like diplopia, vertigo, ataxia, dysphagia
How can a physician tell if a TIA is due to a thrombus or an embolus?
Thrombus: multiple similar events like facial numbness that comes and goes over and over.
-slow and progressive
Embolus: multiple dissimilar events like facial numbness, then hand numbness, then to trunk numbness.
-seizures w/ sudden onset
-specific focal deficit
How can a patient be asymptomatic with an Internal Carotid Occlusion?
Some people have a very well developed circle of willis that allows a lot of collateral circulation. A blocked internal carotid territory can be aided by the other side in these people.
Others may not have as well developed vasculature and may present with severe stroke symptoms.
Review: the internal carotid artery officially continues as what vessel from the circle of willis?
Middle Cerebral Artery
What are the major symptoms of a patient with an Anterior Cerebral Artery occlusion?
-hemiplegia and/or hemianesthesia of the leg more than face or arm
-apathy (if frontal lobes are affected)
What are the major symptoms of a patient with a Middle Cerebral Artery occlusion?
-Hemiplegia and hemianesthesia of the face and arm more than leg
-aphasia (if dominant hemisphere is affected)
Describe Broca Aphasia.
Nonfluent, repetition impaired, comprehension spared.
Can't produce speech but can understand it and follow directions
Describe Wernicke Aphasia.
Fluent, impaired comprehension, repetition impaired, gibberish
Patients can speak but cannot comprehend
Describe Conduction Aphasia.
Lesion in the arcuate Fasciculus (area containing peri-sylvian connections between Broca and Wernicke)
-patient has difficulty with repitition. They cannot read out loud.
Describe Global Aphasia.
Usually caused by MCA occlusion and all aspects of speech are affected. Both Broca and Wernicke are affected.
What symptoms result from a posterior cerebral artery occlusion?
1. Homonomous hemianopia
2. Hemiplegia or hemiparesis (due to thalamus or cerebral peduncle affected)
What are lacunar infarcts?
Small vessel disease: occlusion of tiny branching vessels in the brain. Usually have very focal symptoms like: pure motor, sensory, pseudobulbar palsy etc. Usually occur in the white matter areas.
Biggest risk factor for Small vessel disease.
How is taking oral contraceptives while smoking a risk for stroke or small vessel disease?
The combination increases coagulability and formation of clots.
Describe Weber Syndrome (in the depth Dr. Esper wants us to know).
Midbrain stroke resulting in:
-CN III palsy
Describe Wallenberg Syndrome (in the depth Esper wants us to know).
Occlusion of vertebral artery or PICA resulting in:
-ipsilateral facial numbness
-dysphagia, hoarsness, loss of taste
-contralateral loss of Pain and Temp
What is the key to controlling BP in post-stroke patients?
Gradually reduce the blood pressure. You do NOT want to give medication that will cause a drastic drop because this could decrease blood flow to the brain.
What is an ischemic penumbra?
Generalized region of the brain surrounding the primary area of infarct that can usually be saved with rapid aggressive treatment.
The primary area of infarct is usually lost.
In order to salvage the Penumbra, what should be avoided and what drug class has shown promise in the research field?
Avoid: relative hypotension, hypoxia, hyponatremia, hyperglycemia
Neuroprotective Agents: NMDA, NO, GABA, calcium, free radical
How can a CT aid in treatment for acute strokes?
CTs can identify the presence of blood:
-if blood is present you do not want to use clot busters b/c it is a hemorrhagic stroke and will increase the blood loss
-if blood is NOT present, the next step is clot busters because it is an ischemic stroke caused by an embolus or thrombus
How does aspirin treat strokes?
Anti platelet agent that breaks up clots and prevents vessel occlusion.
Important not to give too high of a dose in order to prevent GI disturbance
How does Ticlopidine treat strokes?
Prevents ADP from binding and activating fibrinogen (forming fibrin) preventing the formation of clots.
Risk of neutropenia and thrombocytopenia
How does clopidogrel treat strokes?
Prevents ADP from binding and activating fibrinogen (forming fibrin) preventing the formation of clots.
Not as many side effects as Ticlopidine
What drug can be used with aspirin to decrease the chance of stroke?
What is the drug of choice for a patient suffering a cardioembolic TIA?
Other than treating hypertension, what drug class is very effective for decreasing risk of stroke?
-pts. with LDL <70 if they have already had a stroke
Surgery is recommended in patients with Symptomatic Carotid Stenosis if the artery is occluded by how much?
Surgery is recommended in patients with Asymptomatic Carotid Stenosis if the artery is occluded by how much?
How does Tissue Plasminogen Activator work?
By converting plasminogen to plasmin, fibrin is broken down to prevent further clotting.
What conditions need to be met before using TPA?
Basically NO BLEEDING
-CT scan negative for blood or stroke
-BP must be <185/110 (if not use labetalol to decrease BP)
-no recent trauma or surgery
-no seizure as a result of bleeding
-no intracranial tumor, arteriovenous malformation or aneurysm
-no use of blood thinners
What is hypertensive encephalopathy?
Headache, confusion, seizure, and a focal deficits (motor or sensory) as a result of malignant hypertension and loss of cerebral autoregulation. In pregnancy it is called eclampsia.
Treat with BP control.
What is the number one risk and common features of Idiopathic Intracranial Hypertension?
#1 risk is obesity
Features: headache (most common), papilledema, CN palsy
How is Idiopathic Intracranial Hypertension diagnosed and treated?
Diagnose with spinal tap pressure (>250mm H2O) or MRI
Treat: diuretics, surgery (drain CSF)
Why is pregnancy a risk factor for venous thrombosis?
Pregnancy increase coagulability
What blood thinner can be used in pregnant patients?
(warfarin and Coumadin are teratogenic)
What is the biggest danger and cause of death with cerebral edema?
What are the 3 types of cerebral edema.
Name the cause, location, and associations of vasogenic edema.
Cause: increased capillary permeability
Located in White Matter (gray/white junction visible on CT)
Associated with tumors or hematomas (NOT stroke)
Describe the mechanism, location, and associations of cytotoxic edema.
Mechanism: cellular swelling due to electrolyte imbalance
Located in gray and white matter (no gray/white junction visible on CT)
Associated with hypoxia and infarction
Describe the mechanism, location, and association with interstitial edema.
Mechanism: CSF flow obstruction
Located in periventricular extra-cellular fluid
Associated with Hydrocephalus
Best treatment of cerebral edema.
-decrease in CO2 leads to vasoconstriction and less fluid in the cranial vault
(can also give diuretics)
What type of edema can steroids and osmotherapy be used for?
What vessels rupture in an Intraparenchymal hemorrhage?
Small penetrating arteries (from ACA, MCA, or PCA)
-usually bleed into the putamen, thalamus, pons, cerebellum
Most common cause of subarachnoid hemorrhage and the vessels that rupture.
Trauma causes rupture of ACA, MCA, or PCA.
What is the most common type of aneurysm that leads to subarachnoid hemorrhage?
Berry aneurysm (saccular)
-most are located at bifurcations of vessels
What two conditions are associated with subarachnoid hemorrhage?
Polycystic Kidney disease
Coarctation of the Aorta
The Hess and Hunt scale grades the severity of subarachnoid hemorrhage. Describe the I-V scale.
I: asymptomatic; slight headache
II: moderate to severe headache; nuchal rigidity
III: drowsy; mild focal deficit
IV: semicomatose, posturing
V: deep coma; decerebrate rigidity
What are the most effective treatments for subarachnoid hemorrhage?
Coiling: platinum coils are deposited at the site of the aneurysm thru a catheter. The coils induce clotting to block off the ruptured vessel.
Which Hess and Hunt scale ratings for SubArach hemorrhage are best treated conservatively?
IV and V
What are mycotic aneurysms and how should they be treated?
Septic emboli that lodge in the vessel wall causing weakness and rupture of the vessel.
Treat by stopping the infection (usually bacterial endocarditis).
What are two treatments for arteriovenous malformations?
Embolization: inducing an embolus to lodge into the vessels of the AVM to shrink and close off some of the collateral circulation
Vessel that ruptures in epidural hematoma and the best treatment.
Middle meningeal artery
Treatment is surgery
What vessels rupture in a subdural hematoma?
Bridging cerebral veins.