Stroke and TIA Flashcards
- Definition of Stroke and TIA in general?
- What are the causes of brain ischemia? 2
- What are the causes of brain hemorrhage?
- Definition: Alteration of cerebral blood flow
- Brain ischemia
- Thrombosis,
- embolism or systemic hypoperfusion - Brain hemorrhage
- Intracerebral hemorrhage
Name the vessels in the cerebral arterial circulation (circle of willis)
8
See picture
Arterial cerebral circulation
Note the posterior circulation and it’s major blood supply. Why is this interesting?
What is the most common vessel for ischemic stroke?
Posterior circulation in the area of the cerebellum and brainstem strokes are not as common but since they involve the brainstem they have terrible outcomes
MIddle cerebral artery
What is the most common type of stroke?
What are the cardiac sources of ischemic stroke?6
What are the other causes of ischemic stroke? 4
Ischemic stroke is the most common stroke type.
CARDIAC CAUSES
- Atrial fibrillation
- ASD/VSD
- Recent AMI
- Endocarditis
- Caradiac tumor
- Valvular disorder
OTHER CAUSES
- Atherosclerotic plaques
- Vasculitis
- Prothrombotic state
- Cerebral hemorrhage
–(20% of strokes)
How could atherosclerotic plaques cause stroke?
2
- Emboli from rupture
- Lack of perfusion from stenosis of vessels
AFIB cause of stroke:
- Commonly from what?
- What area does it come from in the heart mostly?
- Therapy to decrease the risk of stroke? 2
- Embolization of intracardiac thrombi
- Most commonly from the left atrial appendage
3.
- Anticoagulation decreases the risk of stroke by up to 70%
- Aspirin decreases the risk of stroke by 20-25%
What are two congenital sources of stroke?
- Atrial septal defect
- Ventricular septal defect
If atrial septal defect is associated with what it can cause stroke?2
What about VSD?
1
ASD
- If associated with a R to L shunt can cause stroke
- Patent foramen ovale
Ventricular septal defects
- If associated with a R to L shunt can cause a stroke
- When is stroke most common in MI?
- What area of the heart is most responsible for this?
- What are the factors of the event that lead to stroke? 3
- Most common in patients after an anterior wall infarction
- Left ventricular wall mural thrombi
3.
- Large infarctions
- LV dilation
- CHF
- The emboli from endocarditis is from what?
- Cardiac tumors can cause strokes how? 3
- Endocarditis
- Emboli from vegetations - Cardiac tumor
- Obstruction of blood flow
- Can lead to arrhythmias (like afib)
- Embolization of tumor fragments
- What is the most common valve disorder that causes stroke?
Rheumatic mitral stenosis is the most commonly associated with stroke
What are the two kinds of hemorrhagic strokes that equally make up the 20% of strokes?
- Spontaneous intracerebral hemorrhage (10% of all strokes)
- Subarachnoid hemorrhage (the other 10% of hemorrhagic strokes)
Subarachnoid hemorrhages can be from what? 2
- Intracranial aneurysm
- Arteriovenous malformations
Causes of spontaneous intracerebral hemorrhage
3
- Associated with poorly controlled hypertension
- Bleeding disorders
- Amyloid angiopathy
- Spontaneous intracerebral hemorrhages associated with poorly controlled hypertension are often found where?
- Less commonly where?
- What are also associated with HTN or DM?
Commonly located in the
- basal ganglia and
- less commonly in the pons, thalmus, cerebellum or cerebral white matter
- Lacunar infarcts are associated with HTN or DM
How does amyloid angiopathy cause stroke?
Amyloid deposits lead to weakening of the cerebral blood vessels resulting in stroke
Causes of subarachnoid hemorrhage
6
- Trauma
- Spontaneous SAH is usually related to a ruptured AVM or aneurysm
- Abnormal vascular composition (amyloid angiopathy or dissection)
- Illicit drug use such as cocaine or amphetamines
- Intracranial arterial dissections
- 20% may have no identifiable cause
- Intracranial aneurysm is most commonly located where?
- How do aneurysms typically present?
- What determines the risk of ruptures? 2
- In general, size over ____carries a high risk of rupture
- Most commonly located in the circle of Willis
- Aneurysm is usually asymptomatic until rupture
- Size and location determine the risk of rupture
- In general, size over 1 cm carries a high risk of rupture
Describe the pathophysiology of Arteriovenous malformations?
2
- Abnormal arterial to venous connection
- The venous side will often develop pressures as high as arterial which leads to rupture.
- Arteriovenous malformation pts are at risk for stroke and what else?
seizures
Name the subtypes of hemorrhagic stroke? 2
Name the subtypes of ischemic strokes? 3
- Hemorrhagic
Intracerebral hemorrhage
Subarachnoid hemorrhage
- Ischemic
Anterior circulation
Posterior circulation
Lacunar
- Intracerebral hemorrhage definition?
- Major causes? 6
- Accumulation of blood over minutes to hours forms what?
- As this grows what increases?
- Arterial bleeding directly into the brain parenchyma
- Major causes:
- HTN,
- trauma,
- bleeding disorder,
- amyloid angiopathy,
- illicit drug use,
- AVMs - Accumulation of blood over minutes to hours forming a localized hematoma
- Neurologic symptoms increase gradually as the hematoma grows
Intracerebral hemorrhage:
- What is destroyed as the hematoma enlarges?
- What makes this life-threatening?
- How would this stroke have a higher morbidity and mortality?
- Goal of treatment?
- Brain tissue is destroyed as the hematoma enlarges.
- Pressure created by blood and surrounding brain edema is life-threatening
- Large hematomas have a high mortality and morbidity.
- The goal of treatment is to contain and limit the bleeding.
- What are the two major causes of subarachnoid hemorrhages? 2
- Bleeding into where? 2
- Aneurysm bleeds into the CSF under arterial pressure and increases what?
- How long does bleeding last? and what is a common risk?
- 2 major causes are ruptured aneurysm (most common) or AVM
- Bleeding into the CSF and the space surrounding the brain
- increases the intracranial pressure
- Bleeding lasts a few seconds but rebleeding is common
Subarachnoid hemorrhage
Main treatment goal? 2
- Main treatment goal is identification of source of bleeding and treatment before rebleeding occurs.
- The other goal of treatment is to prevent brain damage due to delayed ischemia related to vasoconstriction of intracranial arteries.
The other goal of treatment is to prevent brain damage due to delayed ischemia related to vasoconstriction of intracranial arteries.
Blood within the CSF induces what?
vasoconstriction, which can be intense and severe
2/3 of all ischemic strokes affect the anterior circulation: Which vessels? 2
Middle cerebral artery
Anterior cerebral artery
MCA is the most commonly involved vessel in ischemic stroke due to what?
the direct flow from the internal carotid artery and it’s large size
Blood supply to the posterior portion of the brain, including the occipital lobes, cerebellum and brainstem. What are arteries are involved?
- Vertebral artery
- Basilar artery (90% mortality)
- Posterior cerebral artery
Ischemic strokes: Lacunar infarcts are what?
Where can you see them? 6
Small lesions (less than 5mm) that occur in the penetrating arterioles in the
- basal ganglia,
- pons,
- cerebellum,
- internal capsule,
- thalamus and
- deep cerebral white matter
- How would you describe the prognosis of lacunar strokes?
- What are they often seen as on a CT? 2
Less morbidity and mortality than other strokes
On CT sometimes seen as
- “punched-out hypodense areas” but sometimes
- no abnormalities can be seen
- What is by far the most common subtype of stroke?
- What is the culprit vessel in most ischemic strokes?
- Anterior strokes occur from what?
- Posterior strokes occur from what?
- By far the most common type of stroke is ischemic
- The MCA is the culprit vessel in most ischemic strokes
- Anterior strokes occur from occlusion off the internal carotid artery or it’s branches
- Posterior strokes occur from occlusion off the vertebral artery or it’s branches