Cerebrovascular Diseases (CVD)
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- Name the four common etiologies of Cerebrovascular disease
- ischemia/hypoxia, infarction, hypertensive CVD, intracranial hemorrhage
- Characterize the two types of ischemic CVD
- Global- caused by a fall in cerebral perfusion pressure below that compensated by autoregulation(45-170mmHg)& Focal ischemia- due to stenosis or arterial occlusion
- Discuss the etiology of Global Ischemia
- cardiac tamponade (low blood pressure) or raised intracranial pressure (trauma) results in infarction accentuated in watershed areas or areas where two blood supplies anastamose (parasaggital)
- What neuronal populations are most sensitive to hypoxia?
- CA1 in hippocampus, Layer 3 & 5 ex/internal pyramidal cells in the cerebral cortex, Cerebellar purkinje neurons
- In general what neurons are most susceptible to hypoxia?
- Large ones
- What are the major causes of brain hypoxia?
- Low O2 Content (Carbon monoxide poisoning), ischemia, histotoxic hypoxia-an inability of the tissue to utilize the oxygen (cyanide poisoning)
- What are the morphological changes associated with hypoxic neurons?
- Neurons turn pink or red and pyknotic (neurons shrink and become obscure)
- Define stroke.
- A clincial term used to describe a cerebrovascular accident/focal neurological deficit due to a vascular disorder syndrome lasting greater then 24 hours. (70%)infarction or (30%)hemorrhage.
- Define cerebral infarction.
- Vascular necrosis characterized by death of all cellular components.
- What are some common causes of cerebral infarction?
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Embolic events-atherosclerotic
Thrombotic events- basilar artery
Venous occlusion- related to infectious processes - How does one categorically date infarctions?
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Acute- identical to global ischemia PMN infiltrate
Subacute- Macrophage infiltration, increase in vasculature.
Remote/cystic- cavitary lesion with some gliotic cells - What is the major manifestation of hyertensive cerebrovascular disease?
- Intracerebral hemorrhage, lacunar infarct, subcortical atherosclerotic leukoencephalopathy and hypertensive encephalopathy
- What are the major areas of the brain affected by hypertensive cerebral artery disease.
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Hemorrhage in basal ganglia straight striate arteries (have a right angle thus very susceptible to changes in bp)
Brainstem (another common area) is fatal - Descirbe and discuss the etiology of the lacunar infarct.
- small cavitary infarct seen in the basal ganglia and the thalamus associated with HTN...typically Asympotomatic unless it occurs in the anterior limb of the internal capsule
- Discuss/Describe the etiology of subcortical atherosclerotic leukoencphalopathy.
- Slow gradully progressive disease associated with the elderley, AD, hypertension and dementia
- What is hypertensive encephalopathy?
- Occurs in the setting of a sudden rise in bp (>200)eliciting a severe headache, vomitting and visual auras...predisposed by pregnancy or glomerular nephritis
- What are the three different manifestations of intracranial hemmorrhage?
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Subarachnoid
Intraparenchymal
Epidural- traumatic rupture of the middle meningeal artery in the epidural space
Subdural- seen in elderley associated with senescent atrophy of brain and stretching of vasculature...associated with very minor trauma in elderly - What are the major risk factors associated with intracranial hemmorrhage?
- Hypertension, ruptured annuerysm and vascular malformation.
- Discuss the common etiology of Subarachnoid Hematoma?
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1. Non-traumatic rupture of a saccular or berry annuerysm
2. Vascular malformation (5%)
3.infectious/mycotic annuerysm - Where are the majority of annuerysms localized?
- 90% Anterior circulation, 10% posterior
- What are the most common causes of vascular malformation?
- Arteriovenous malformation (embedded in CNS tissue)second most common cause of SAH, cavernous hemangioma (not embedded), cavitary telengectasia and venous angiomas- clinically silent.
- In what patient population do Arteriovenous malformations typically present?
- middle aged SAH/focal ischemia, blood shunted from arterial to venous system bypassing arterial bed and resulting in focal ischemia.
- Discuss Cerebral Amyloid Angiography.
- Manifests as lobar hemorrhage. Always associated with dementing disease such as Alzheimers. Deposition of AB peptide distinguishing it from systemic amyloidosis. Congo (+)
- What are some etiologies of intraparenchymal hemorrhage?
- Drug abuse, tumors, AVM, hypertensive hemorrhage.
- What are the leading causes of death in the U.S
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Heart DZ
Cancer
Cerebrovascular DZ