Stroke Flashcards
What is a stroke
Acute onset of neurological deficits lasting for more than 24h due to disturbance in blood supply to the brain
Modifiable risk factors for stroke
Hypertension Diebetes Hyperlipidemia (high cholesterol) Smoking Obesity Carotid artery disease
Different types of smoke
Ischaemic: thrombotic (plaque forms in brain) or embolic (large vessel occlusion).
-thrombotic strokes can be lacunar occlusions (in smaller blood vessels) or in large vessels
Haemorrhagic: intercerebral or subarachnoid
Symptom of haemorrhage
thunderclap headache
Seizures
Nausea
Unilateral weakness
When a blockage of anterior circulation occurs, which blood vessel is affected
Middle cerebral artery
Carotid arteries
What does the anterior cerebral artery supply and therefore what does a stroke in this region look like
Middle of brain in the longitudinal fissure
-Stroke looks like its close to the midline
Symptoms of stroke in anterior circulation
Hemiplegia/paresis Hemisensory loss Hemianopia (loss of vision in part of field of view of both eyes) Dysphagia Aphasia (language disturbance)
Symptoms of stroke in posterior circulation
Bilateral sensory/motor deficits
Dis-conjugate eye movement
Cerebellar dysfunction
Isolated hemianopia (not in combination with other anterior stroke symptoms)
Non specific symptoms of stroke
confusion, drowsiness, dizziness
nausea, double vision
Incontinence
What are lacunar infarctions
Small, strategic strokes in penetrating arteries that feed sub-cortical structures
What is motor hemiplegia syndrome
Infarction in the posterior limb of the internal capsule, basal ganglia or pons
What us the most common stroke
Middle cerebral artery infarction, which results in contralateral hemiplegia and hemisensory loss
What can CT be used to detect and what is it not good at detecting
Good at detecting haemorrhage
Less effective at detecting acute ischaemic stroke
What does intra-cerebral haemorrhage look like on CT
Wedge-shaped
What does an ischaemic stroke look like on CT
Sulci are less prominent
Loss of basal ganglia definition
Treatment of haemorrhage
Involves pain management and surgery to repair the bleed with clipping or coiling
Lower blood pressure with Labetalol or GTN (glyceryl trinitrate)
How do you treat ischaemic stroke
Thrombolysis with Alteplase (recombinant tissue plasminogen) WITHIN 3H
Thrombectomy with retriever devices within 6h
Why does Alteplase need to be given quickly
Because the Penumbra (layer in artery) will die off quickly if it doesn’t receive oxygen/nutrients within time frame
How is stroke diagnosed
Neurological exam followed by neuroimaging
How is the core of the cerebellar arteries affected in strokes
Core is irreversibly damaged tissue
What happens when cells are deprived of glucose and oxygen
1) sodium/calcium channels dysfunctional so they both flood into cell and depolarise it. Cell fires an action potential
2) water enters cell and cell swells.
3) potassium ions leave cells and come into contact with other cells and cause other cells to depolarise
4) Build up of glutamate in ES space. further stimulates further calcium release
5) Calcium inside cell induces enzymes and causes release of free radicals (N.O) or degrade the membrane
6) free radicals cause inflammation
7) Microglia become really active and release inflammatory cytokines. Microglia also release cytokines which release leukocytes from blood vessels which come into the brain (because BBB is broken) which also contribute to inflammation
8) Ca2+ inside cell also causes mitochondrial damage which causes apoptosis. DNA damage also causes apoptosis
What can be used to reduce risk of reoccurrence of stroke
Anti-coagulants and lipid lowering drugs
What cerebrovascular pathologies associated with Vascular Cognitive Impairment can be visualised with neuroimaging
White matter change Lacunar infarction Microbleeds Enlarged perivascular spaces Cerebral amyloid antipathy
