Flashcards in Stroke Mechanisms (Rybinnik) Deck (11):
Define cerebral infarct.
type of ischemic stroke resulting from a blockage in the blood vessels supplying blood to the brain
Distinguish between the mechanisms underlying ischemic and hemorrhagic stroke.
What are the differentiating clinical features.
Ischemic: clot within vessel stops blood flow to an area of the brain -> deprive neurons of oxygen and nutrients
Hemorrhagic: blood begins to fill brain space (mass effect)
Differentiating clinical features:
Explain the contraindications of tPA in treatment of acute stroke.
tPA = tissue plasminogen activator (for blood clots)
- active internal bleeding
- acute intracranial hemorrhage
- recent intracranial or spinal surgery or serious head trauma
Distinguish between the mechanisms and symptoms of lacunar and large-vessel strokes (both ischemic thrombotic stroke subtypes)
Lacunar (not cortex): Small-vessel subcortical lesions - body able to adjust so takes decades for clot to make an impact (circle of willis)
Large-vessel (cortex): atherosclerosis (intracranial or extra cranial i.e. middle cerebral artery)
List the risk factors for embolic stroke.
Cardiac, artery to artery
Clinical features: maximal deficit at onset
- atrial fib (when this happens, there's a stasis of blood in the LA -> when blood goes back to normal rhythm, that clot gets pushed up to the brain)
- cardiac tumors
- valvular disease
Describe (generally) the most common sites for hemorrhagic strokes.
Basal ganglia / Thalamus (arterioles off MCA and PCA) - 50% - HTN
Lobar (penetrating branches of ACA, MCA, PCA) - 33%
Brainstem Cerebellum (Branches of basilar, PICA
Describe the major risk factors for hemorrhagic stroke.
Describe the features of A-V malformation.
Arteries and thin walled veins connected
Lack of capillaries -> therefore, no oxygen exchange
List the signs of subarachnoid hemorrhage.
Severe headache (97%) - worst headache of life
Describe the mechanisms of venous stroke.
Impaired drainage causing brain swelling and damage
- Thrombosis of cerebral veins