Cerebral infarction/understanding Stroke Flashcards
Definition of stroke
sudden onset of focal or global neurological symptoms caused by ischemia or haemorrhage and lasting more than 24 hours.
85% are ischaemic - clot stops blood supply to an area of the brain
15% haemorrhagic - blood leaks into brain tissue
Define TIA
term used if the symptoms resolve within 24 hours.
Most TIAs resolve within 1-60 min
warning sign - 10% stroke recurrence within first 2 weeks of TIA
Causes of ischaemic stroke
Large artery atherosclerosis (carotid) - plaque etc
Cardioembolic (AF) -Valve disease or LV thrombus
small artery occlusion
Causes of haemorrhagic stroke
- primary intracerebral haemorrhage 70%
2. secondary haemorrhage 30%- subarachnoid haemorrhage or anteriovenous malformation
Risk factors of stroke: modifiable and non-modifiable
Modifiable:- Hypertension - most important modifiable RF smoking Obesity Exercise/physical activity Diet/High cholesterol Drugs diabetes
Non-modifiable:- Previous stroke Age Male Family history
What can chronic hypertension exacerbate?
atheroma and increases involvement of smaller distal arteries
What does Hypertension, cigarette smoke and diabetes contribute to?
LDL-C deposition in arterial walls - low-density lipoprotein ‘bad’ cholesterol
Other risk factors
other cardiac causes - recent heart attack etc
oral contraceptives with high estrogen content
hyper-coagulable states - malignancy, genetic
Anterior circulation in the brain
2 internal carotid arteries
2 anterior cerebral arteries
2 middle cerebral arteries
Posterior circulation in the brain
2 vertebral arteries - 1 basilar
3 pairs of cerebellar arteries
2 posterior cerebral arteries
What are the borderzone anastomoses?
between peripheral branches of anterior, middle and posterior cerebral arteries
Functions of frontal lobe
memory voluntary eye movement motor control of speech (dominant) motor cortex urinary continence emotion and personality
If the Middle cerebral artery is affected then what type of weakness is more common
face and arm weakness
If the anterior cerebral artery is affected then what type of weakness is more common
leg weakness
Clinical presentations of stroke
Sudden onset loss of function: Motor (clumsy or weak limb) Sensory (loss of feeling) Speech: Dysarthria/ Dysphasia Neglect / visuospatial problems Vision: loss in one eye (amaurosis fugax) or hemianopia Gaze palsy
ataxia/vertigo/incoordination
True or false: Abnormal movements and severe headache is unusual after stroke?
True
What is the Oxford Community Stroke Project Classification (OCSP)
A clinical classification tool that predicts the site and size of the infarct on CT
What are the 4 classes of stroke
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What does agnosia mean
inability to process sensory information
Name some neglect syndromes/agnosias
Visual agnosia
Sensory agnosia
Anoagnosia (denial of hemiplegia - paralysis of
one side)
Prosopagnosia - failure to recognise faces
Effects of Total Anterior Circulation Syndrome (TACS)
3/3 of effects:- Complete hemiparesis/numbness
Loss of vision on one side (hemianopia)
Loss of awareness on one side (inattention) non-dominant
or dysphasia dominant
What is TACS often caused by?
blocked Carotid or middle cerebral artery
Effects of Partial Anterior Circulation Syndrome (PACS)
2 of 3 TACS criteria
or
One higher cortical deficit:
Inattention or dysphasia
or
Monoparesis
Lacunar syndrome (LACS)
Subcortical stroke
=> secondary to small artery disease/perforation
Movement and sensation pathways
Weakness/numbness of:
Face + arm + leg
Or Face + arm
Or Arm + leg
May have dysarthria - difficult with articulation of speech
Ataxic hemiparesis - weakness and ataxia on the same side
No affect on higher function
Will not have dysphasia, inattention or hemianopia
