Cerebrovascular Disease Flashcards
Two forms of cerebrovacular disease ?
1) Hypoxia, Ischemia, infarction; impairment of blood supply and oxygenation of CNS tissue
2) Hemorrhagic; rupture of CNS vessels
Common etiology of CNS infarction?
Embolism, can be global or focal
Common etiologies of hemorrhagic accident in the CNS
- Hyoertension
- Vascularanomalies (aneurysms and malformations )
- trauma
Stroke is defined as ?
Sudden onset of neurological deficit resulting from hemorrhage or or focal ischemia
Epidemiology of cerebrovadcular disease?
- their most common cause of death: (after heart disease and cancer)
- most common cause of neurological morbidity and mortality
Biological process that takes place in ischemia?
Ischemia leads to
- ATP Depletion
- loss of membrane potential needed for neuronal electrical activity
- elevation of cytoplasmic calcium levels
- inappropriate release of excitatory amino acid neurotransmitters that cause cell damage via calcium influx
- Glutamate release through N methyl D aspartate type glutamate receptors (NMDA)
Zones of ischemic injury
1) umbra - necrotic tissue
2) penumbra - At risk tissue
Clinicalpathologic form of CVD includes?
- Global cerebral ischemia (diffuse ischemic encephalopathy)
- Transient ischemic attack ( TIA)
- Stroke ( hemorrhagic or ischemic )
Causes of diffuse ischemic encephalopathy
- fall in blood flow to the brain (shock, cardiac arrest, hypotension)
- Infarcts in watershed areas (between anterior and middle cerebral arteries)
- Damage to vulnerable regions (purkinje neurons, hippocampus pyramidal cell layer -CA1 (sommer sector), pyramidal neurons of the cortex )
- cortical laminar necrosis *(diffuse ischemic necrosis of the neocortex, may lead to brain death)
Morphological features of DIE
- Gross; ischemic areas are edmatous with widened gyri and narrowed sulci
- Loss of hey and white matter differentiation
Pseudo-laminar necrosis pattern is formed from?
Uneven cortical neuronal loss and gliosis alternating with preserved zones
TIA symptoms last for about how many hours?
- less than 24hrs
- Due to small platelet thrombi or artheroemboli
Infarction (85%) in stroke can be due to ?
1) thrombotic occlusion
- atherosclerosis of the cerebral arteries
- leads to anemic /white infarcts
2) embolic occlusion
- leads to hemorrhagic infarcts
- throboemboli from cardiac chambers
3) small-vessel disease
- related to hypertension
- hyaline atherosclerosis
- leads to lacunae infarcts/lacunae
Inflammatory process that leads to infarction include?
- Infectious vasculitis
- Polyarteritis nodosa
- Primary angitis of the CNS
Microscopic changes associated with cerebral infarction
Microscopy**:
- Red neurons (12-24hrs after injury)
- neutrophilic infiltration (24-48hrs)
- histiocytic infiltration and disappearance of neurons (2-10days)
- liquefactive necrosis, histiocytes filled with products of myelin breakdown (2-3weeks)
- fluid filled cavity, reactive astrocytes, lipid-layden macrophages (glitter cells) (3 wks- 1 month )
- Reactive gliosis (astrogliosis) - (years after)
Gross changes associated with infarction
- Little to no change in cerebrum (0 - 24hrs)
- Indistinct gray-white mater junction (24-48hrs)
- friable tissue with marked edema (2-10days)
- tissue liquefies (2-3weeks)
- fluid filled cavity demarcated by gliotic scar (3weeks to months)
- old cyst surrounded by gliotic scar (years)
What causes white infarcts and red infarcts?
Thrombosis - white infarcts (anemic infarcts)
Embolism - red infarcts ( hemorrhagic infarcts)
Lacunae Infarcts Commonly affect?
- The putamen and caudate
Intra-cerebral hemorrhage / Intraparenchymal hemorrhage most commonly caused by?
Hypertension:
- Basal ganglia (putamen in 50% - 60% of cases)
- Thalamus, pons, centrum semiovale and cerebellum rarely
Other causes of intracerebral hemorrhage?
- Vascular malformations (AVMs)
- Cerebral amyloid angiopathy
- Neoplasms
- Vasculitides
- Abnormal hemostasis
- Hematological malignancies
- Infection
Symtoms of hemorrhagic strike?
- Severe headache
- Frequent projectile vomiting and nausea
- Steady progression of symtoms over 15-20mins
- Coma
Intracerebral hemorrhage account for how many percentage of death in chronic hypertensive patients ?
- 15% of death in chronic hypertensive patients
How does hyoertension lead to hemorrhagic stroke ?
1) hypertension leads to weakening of the vessel through hyaline arteriosclerosis
2) Focal vessel necrosis
3) formation of micro-aneurysms (Charcot Bouchard aneurysms)
The second most common etiology of Intraparenchymal hemorrhage is ??
Cerebral amyloid angiopathy (CAA)
- Amyloidogenic oeotide deposit in vessel walls leading to weakening of vessels.
Similar to that in Alzheimer’s disease
stiff Amyloid deposition characteristically involves the?
leptomeningeal and cerebral cortical vessels
A rare form of.stroke caused by NOTCH3 receptor mutation is ?
CADASIL - cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy
- abnormal folding of extra cellular membrane
- concentric medial and adventitial thickening
- Basophilic granular osmophilic deposits and smooth muscle dropout
Most common cause of SAH?
Ruptured berry aneurysms
- extension of intracerebral/subdural hematoma
- vascular malformations
- trauma
- hypertensive intracerebral hemorrhage
- abnormal hemostasis
tumors
Symptoms of SAH?
- Thunderclap headache
- Nuchal rigidity
- Neurological deficiency on one side
- Stupor
Berry aneurysms are ?
- Thin walled saccular out-pouching, consisting of intima and adventitia only
- congenital focal weakness of an artery, not identifiable at birth
- occur in 2% of the population
- 20-30% of patients have multiple aneurysms
- most cases are sporadic
Most common site of berry aneurysms is?
The anterior circle of willis at branching points
- Anterior cerebral artery branching
Disorders associated with berry aneurysms ?
- Marfan syndrome
- Ehler Danlos syndrome type 4
- Neurofibromatosis type 1
- Fibromuscular dysplasia
- Adult polycystic kidney disease
Risk factors for berry aneurysms?
- Cigarette smoking
- Hypertension
Epidemiology and prognosis go berry aneurysms
- Rupture is precipitated by sudden increase in blood pressure
- slightly more common in women in 5th decade of life
- prognosis; 1/3 Die, 1/3 recover, 1/3 rebleed
List the vessels involved in the different type of Cerebral hemorrhages?
- Epidural hematoma - middle meningeal artery
- subdural hematoma - Bridging veins
- subarachnoid hemorrhage - Berry aneurysm rupture
- Intraparenchymal hemorrhage- chronic hypertension
The most important effects of hypertension on the brain include ?
- Lacunar infarcts
- slit hemorrhages
- hypertensive encephalopathy
- massive hypertensive intracerebral hemorrhage
What are lacunar infarcts?
Small (<15mm) cystic infarcts resulting from cerebral arteriolar sclerosis and occlusion
Tissue loss is accompanied by Lipid laden macrophages and surrounding gliosis
Most commonly affected spots in lacunar infarcts?
- Lenticular nucleus
- Thalamus
- Internal capsule
- Deep white matter
- Caudate nucleus
- Pons
Slit hemorrhages occur when?
Occurs when hypertension causes small vessels rupture
They resorb but leave residual hemosiderin laden macrophages and associated gliosis
AHE (Acute hypertensive encephalopathy) is defied as?
- Clinicooathological syndrome caused by Increased ICP
- Manifest as Diffuse cerebral dysfunction
- headcahe, confusion, projectile vomiting, convulsions, coma
- post mortem examination; edematous brain, occasionally with herniation, Petechiae and anterior fibrinoid necrosis
Vascular (Multi-infarct) dementia so
Caused by Recurrent small infarcts
Characterized by
- dementia
- gait abnormalities
- Pseudobulbar signs
Causes of vascular dementia?
- Cerebral atherosclerosis
- Vessel thrombosis or embolization
- Cerebral arteriolar sclerosis
Binswanger disease - Chroninc hypertensive injury
- recurrent ischemic injury involved a subcortical white matter
- myelin and axonal loss
Primary Intraparenchymal hemorrhage are common in what regions of the brain?
- White matter
- Deep gray matter
- Posterior fossa contents
What are boundary zones of the brain?
Regions of the cerebrum with the least robust vascular supply
Dissolution of an embolism and the repercussion can result into?
Hemorrhagic transformation of ischemic infarct
