Pathology of Stroke Flashcards
What vessels supply the cerebral cortex?
Internal Carotid Arteries [70%]
Vertebral Arteries [30%]
Both through circle of willis
Define Cerebral Perfusion Pressure
the difference between systemic arterial blood pressure and intracranial pressure
What causes Global cerebral ischemia?
results from a fall in cerebral perfusion pressure below threshold for autoregulation
What causes local cerebral ischemia?
arterial stenosis or occlusion
What cell in the CNS is most vulnerable to ischemia?
Neurons [pyramidal neurons in hippocampus, Purkinje cells in cerebellum]
What areas of the brain are vulnerable to hypotension or cardiac arrest?
Watershed areas, Cerebral cortex, Hippocampus
Describe the microscopic appearance of acute neuronal injury in Purkinje cells
deep eosinophilia of cytoplasm and variable degrees of nuclear disintegration
Describe the microscopic appearance of chronic neuronal injury
Neuronal loss and Gliosis [+ edema and demyelination]
Define TIA
term used to describe if symptoms resolve within 24 hours
Define stroke
an “abrupt onset” of focal or global neurological symptoms caused by ischemia or hemorrhage lasting more than 24 hours
What is the most common cause of cerebral infarction?
Atherosclerosis
General epidemiology of stroke
> 70% - cerebral infarction
~ 20% – cerebral hemorrhage
remainder is subarachnoid hemorrhage
What is the 3rd most common cause of mortality in the US?
Strokes
What are risk factors for strokes?
HTN
Lipids
DM
Environmental factors
Obesity
Impaired Cardiac function
Oral contraceptive with high estrogen content
Anti-phospholipis Abs
What risk factor account for 50% of hemorrhagic strokes?
Hypertension
Why is hyperlipidemia considered a risk factor and what does it affect?
Atheroma
carotid arteries > vertebral arteries > circle of willis
What is the link between DM and Strokes?
DM increases incidence of strokes unto 3-folds in both sexes
What environmental factors increased the risk for strokes?
Diets resulting in hyperlipidemia
High salt intake may promote HTN
Smoking
Which cardiac condition increases the risk of stroke and why?
A. Fib
increased risk of embolisation
How does Anti-phospholipid autoantibodies increase risks of strokes?
Associated with recurrent thrombosis
Two most relevant antibodies are anticardiolipin and lupus anticoagulant.
Thrombotic stroke and transient ischaemic attacks
Stroke
Ischemic
Hemorrhagic [intracerebral or subarachnoid hemorrhage]
Pathophysiology of Global Ischemic stroke
Global generalized hypoxic encephalopathy
Hypotension : Acute MI. Heart failure. Shock
Pathophysiology of Focal Ischemic stroke
cerebral infarcts.
Thrombosis: underlying atherosclerosis.
Emboli.
Describe the acute morphology of ischemic stroke
edema neuronal microvacuolization pyknosis karyorrhexis neutrophils
Describe the chronic morphology of ischemic stroke
macrophagesgliosis
In order, list the histopathologic progression of CNS ischemic infarcts
Edema
‘‘red neurons”
polymorphonuclear leukocytosis
monocytes [macrophages]
Gliosis
What type of stroke [embolic, hemorrhagic, thrombotic] hast the fastest onset?
Embolic stroke
What condition causes an emboli from the heart?
from left atrium in AFib
Endocarditis
Cardiac surgery
prosthetic or damaged valves (rheumatic fever, calcific aortic valve disease)
What are four possible causes of emboli?
Atheromatous plaques (carotid arteries)
The heart
fat emboli
Gas
Describe gas as a possible source of emboli
Air or nitrogen as emboli seen in decompression sickness
Describe fat as a possible source of emboli
Fat emboli as a result of trauma [stained with Oil-red O]
What type of stroke is associated with Fat emboli?
multiple petechial haemorrhages in the grey and white matter
What structures are common affected by intracerebral hemorrhage?
Basal Ganglia, Cerebellum
What is the leading cause of intracerebral hemorrhage?
HTN
What is the prognosis of intracerebral hemorrhage?
Lethal conditions but the hematoma can slowly be resorbed over months with from restitution of function
What are causes of Subarachnoid hemorrhage?
Rupture of Congenital [Berry Aneurysmd]
Atherosclerotic and mycotic aneurysms
AV malformation
What is the prognosis of Berry Aneurysms?
Mortality is high. Re-bleeding is common in survivors.
Resorption of blood may lead to meningeal fibrosis & hydrocephalus
What increases the likeness of a berry aneurysms to “rupture” ?
probability increases with size of aneurysm + incidence acutely increases in intracranial pressure [straining at stoll, sex]
What arteries are commonly implicated in Berry Aneurysm?
What types of strokes are associated with Hypertension?
Intracerebral hemorrhage
Lacunar infarcts [basal ganglia]
What is the clinical significance of Lacunar Infarcts?
can be silent or cause serious impairment
What arteries are implicated in lacunar infacrts?
lenticulostriate arteries of internal capsule, Putamen, thalamus, pontine tegmentum, cerebellum.
Describe the gross morphology of lacunar infarcts
Small often cystic infarcts
What is a common site of hemorrhage in hypertensive patients?
Basal Ganglia
