Cerebrovascular Disease NeuroPathology Flashcards
Slow atrophy of nerve cells and/ortheirprocesses most commonly leads to what clinical picture?
graduallyincreasingdysfunction(age- relatedcerebralatrophy)
How does acute neuronal injury appear microscopically?
- Shrunkenandangulated nuclei
- Lossofthenucleolus
- Intenselyredcytoplasm “RED NEURON”
At what stage are “RED NEURONS” normally seen microscopically?
- After hypoxia/ischaemia
- Typicallyvisible12-24hoursafteranirreversibleinsult (stroke)
- shows neuronal cell death
If an axon is severed, what occurs on either side of the damage?
- cellbodyswelling,enlargednucleolus
- Degenerationofaxonandmyelinsheathdistaltoinjury
What are the main functions of astrocytes?
- maintainthebloodbrain barrier
* Involvedinrepairand scarformation(due tolackof fibroblasts)
How do astrocytes usually respond to any CNS injury?
Gliosis => Astrocytehyperplasiaand hypertrophy
-indicatorofCNSinjury,regardlessofcause
How does old gliosis appear histologically?
- nuclei become smallanddark
- They lie inadensenetofprocesses(glialfibrils)
What type of damage are oligodendrocytes particularly susceptible to?
oxidativedamage
How do ependymal cells (which line ventricles) respond to CNS injury?
- Limitedreactiontoinjury
- disruption causes local proliferation of these cells =>smallirregularitiesontheventricularsurfaces”ependymalgranulations”
How do the microglia (macrophage-like cells) respond to CNS injury?
- proliferate
- Recruitedthroughinflammatorymediators
- Aggregate aroundnecroticanddamagedtissues
- M2 more acute, M1 - chronic
Why does the brain deteriorate so quickly once hypoxia and ischemia occur?
- No O2 to create more ATP
- mitochondria inhibitATPsynthesis
=>ATPreserveis consumedwithinafewminutes
Why can excitotoxicity cause oxidative stress in neurons?
- excitatory signal depolarises neuon and releases glutamate
- lack of energy means astrocytes dont reuptake glutamate
- lots of glutamate in synapse causes lots of Ca2+ entry into post-synaptic terminal
=> mitochondrial dysfunction and oxidative stress
What are the main types of edema in the brain?
Cytotoxicoedema - Na+/K+ channel dysfunction => cells retain Na+ and water
Ionic/osmotic oedema - water and Na+ from capillaries move into brain parenchymal extracellular space
Vasogenic oedema - BBB disrupted => leaking fluid from capillaries affects white matter
Haemorrhagic conversion - when RBCs cross BBB
What is meant by cerebrovascular disease?
- an abnormalityofbraincausedbyapathological processinbloodvessels
What is the definition of a stroke?
Suddendisturbanceofcerebralfunction ofvascularoriginthatcausesdeathorlastsover24hours
What gender and age are most common in stroke patients?
Peakageofincidenceis>70yrs
Men>women
Strokes caused by an atherosclerotic thrombus are most common in which artery of the cerebrum?
MiddleCerebralArteryor its branches
Where do embolic strokes usually originate from?
- atheromaininternalcarotidor aorticarch
- emboli from heart due to AF
What are the risk factors for cerebral infarction?
- Hypertension
- Serumlipids,obesity,diet
- Diabetesmellitus
- Heartdisease
- Drugs
- Smoking
What symptoms do patients often experience if they have a stroke due to carotid artery disease?
- contra‐lateralweakness/ sensory loss
- If dominanthemisphere,maybeaphasiaorapraxia
What symptoms would usually indicate a middle cerebral artery stroke?
weaknessin contralateral faceandarm
What symptoms would usually indicate an anterior cerebral artery stroke?
weaknessandsensorylossin contralateral leg
Strokes in the Vertebro‐basilararteries can cause what symptoms?
- vertigo
- ataxia
- dysarthria
- dysphasia
What is meant by vascular remodelling and how can this perpetuate a stroke?
- accelerated atherosclerosis
- arteriolosclerosis (thick, stiff vessel walls prone to rupture)
- Eventual fibrinoid necrosis of vessel walls
Where do micro aneurysms most commonly occur in the brain circulation?
Branches of the middle cerebral artery near the basal ganglia
What is a lacunar infarct?
Small “lake” like infarcts
up to 15mm diameter
due to damage of Lenticulostriate arteries in basal ganglia
When can lacunar infarcts cause the most damage?
If they extend into internal capsule
=> can cause extensive motor weakness in face and limbs
What are the hallmarks of hypertensive encephalopathy?
- globalcerebraloedema
- tentorialandtonsillarherniation (due to raised ICP)
- petechiae
- arteriolarfibrinoidnecrosis => high BP
Where do most intracerebral haemorrhages occur?
- Mostcommonlyinbasal ganglia
- Thalamus
- Cerebralwhitematter
- Cerebellum
How do intracerebral haemorrhages appear macroscopically?
- Asymmetrical
- shiftsandherniations of brain
- Welldemarcated
- Softeningofadjacenttissue
- Surroundingoedema
What vascular malformations can predispose to cerebrovascular disease?
- Arteriovenous malformations
- cavernous/venous angiomas
Why do vascular malformations predispose to haemorrhage?
- Shunting fromarterytovein
=> Vein undergoessmoothmuscle hypertrophy
=> vein is notcompliantandruptureseasily
can also form aneurysms which rupture
What normally causes a subarachnoid haemorrhage?
ruptureofasaccular aneurysm(Berryaneurysm)
Where do Berry aneurysm’s normally occur?
Internal carotid artery
vertebro‐basilarcirculation
usually at arterial bifurcations
What can be seen macroscopically around a Berry aneurysm?
- Intracerebral haematomasnexttoaneurysms
- Infarctsofbrainparenchyma– due toarterialspasm
- Haematoma may compress structures and cause featuresofraisedICP
What are the risk factors for Berry Aneurysms?
smoking
hypertension
kidneydisease
WHat symptoms are usually experienced upon rupture of a Berry Aneurysm?
- Severeheadache
- Vomiting
- Lossofconsciousness
