Stroke Flashcards
Definition
Rapidly developing clinical signs of focal disturbance of cerebral function, last >24hrs or leading to death with no appararent cause of the vascular origin
Types
Ischaemic - 80%
Intra-cranial haemorrhage
Sub-arachnoid haemorrhage
Ischaemic stroke
blocakge of blood vessels to the brain by a clot
Ichaemic stroke can occur by?
Thrombosis: A clot may form in an artery that is already very narrow.
Embolic: A clot may break off from another place in the blood vessels of the brain, or from some other part of the body, and travel up to the brain.
Systemic hypoperfusion - global hypoxia
Thrombotic stroke
Large vessel - Atheosclerosis artery
Small vessel disease - liphyalnosis (wall thickenging and reduced lumen) –> lacunar type stroke
Embolic stroke
cardiac -AF -MI Aortic >3mm atheroma Arterial -atheroma -dissection
Circle of willis !
- Four blood vessels supply the brain
- 2 carotids supply front
o Split into the anterior and middle cerebral arterys - 2 artery’s supply back
o 2 vertebral combine to form the basilar artery
o The split to form posterior cerebral arterys
Pathophysiology of ischaemic stroke
- Embolism or thombus present
- Depending on size of clot, it lodges into relevant size of vessel (large vessel, large clot)
- Rapid decline in cerebral blood flow
- Results in excitotoxicity:
o Neurons release glutamate (excitatory neurotransmitter)
o Glutamate activates calcium and sodium entry into the cell
o Sodium entry, water follows, cell swells and dies
o Calcium entry
Activates enzymes and proteases
Apoptosis
Oxidative damage
Inflammation
o Leads to cell death
Anterior cerebral artery supplies
Anterior and Medial side of brain
Middle cerebral artery supplies
lateral side of the brain
Posterior cerebral artery supllies
occiptal lobes
Map of tissue death
Core- tissue that has died
Penumbra - damaged, but slvageable tissue
Oligaemia - area of low flow
Risk factors for ischaemic stroke
big 5
- hypertension
- smoker
- diabetes
- hypercholesterolaemia
- famil history
Intracerebral haemorrhage pathophysiology
- Blood pressure, tends to cause deep haemorrhage (haemorrhage aound basal ganglia)
- Blood pressure is high around the base of the brain, as vessles extend out towards the edge, pressure drops
- Small BVs are at high risk of rupture in the presence of high blood pressure
Risk factors for intracerebral haemorrhage
- Hypertension!!!!!!!
- Anticoagulants, anti-platelet, warfarin
- Dementia
- Amyloid deposits (cerebral amyloid angiopathy)
- Vascular malformations (drug abuse in youn
Clinical manifestations of stroke
Face Arms Speech Time (FAST)
TACS, PACS, POCS, LACS
TACS (total anterior circulation syndrome)
Artery affected
Total anterior circulation syndrome (TACS)
It is diagnosed when it causes all 3 of the following symptoms:
1) Contra-lateral hemiparesis
2) Contra-lateral hemianopia
3) Higher dysfunction (e.g Dysphasia, Visuospatial disturbances)
+- contralateral hemisensory loss
proximal middle cerebral, or internal cereral artery
PACS (partial anterior circulation syndrome)
Partial anterior circulation stroke (PACS)
When 2 of the above 3 are present or when higher dysfunction alone.
Branch of middle cerebral artery
POCS (Posterior circulation stroke)
It can cause the following symptoms: • Cranial nerve palsy (ipsilateral) with contralateral motor/sensory defect • Bilateral motor or sensory defect • Eye movement disorder • Cerebellar signs • Isolated homonymous hemianopia . Posterior, basilar, cerebellar and vertebral arteries
The hallmark of posterior circulation stroke is that of crossed findings; with
cranial findings on the side of the lesion and motor or sensory findings on the
opposite side
LACS (lacunar stroke)
Lacunar stroke (LACS) Can have the following presentations: • Pure motor stroke/hemiparesis • Ataxic hemiparesis • Dysarthria/clumsy hand • Pure sensory stroke • Mixed sensorimotor stroke
Internal capsule (pure motor), Thalamus (pure sensory) or Pons (ataxia, Contralateral hemiparesis and ipsilateral cerebellar signs)
Perforating artery/small vessel disease
Transient Ischaemic Attack (TIA)
Transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia, without acute infarction and over within 24hours
Baseline investigations
Glucose
- too high dont treat with thromboylsis
- hypoglycaemia (neurological deficit)
FBC, U7Es, LFTS, blood glucose, coagulation profile
ECG- look for atrial fibrillation
CT- easy & quick (eclude mimics, distinguish between haemorrhagic/ischaemic, confrim diagnosis, detects complications and salvagebale tissu)
Vascular
-CT angiogram/MR angiogram/doppler ultrasound
Ichaemic vs haemorrhagic
Cannot distinguish clinically ICH more likely if: - Decreased conscious level - Vomiting - Severe headache - Warfarin - Systolic BP >220 mmHg - Progressive symptoms These results are not absolute, cannot without scan
Treatment of stroke
ACUTE THERAPY
- admitt to stroke unit
- thrombolysis if within 4.5 hours
- give IV alteplase
- only for ischaemic stroke - after 4.5 hours
- aspirin 300mg at FRONT DOOR - neurointervention - if thromboylsis fails (retrieve the clot)
NOTE- if AF give warfarin
