Stroke Flashcards
what are the 2 types of strokes
haemorrhagic (about 10%)
ischaemic (80%)
what are the features of a stroke
rapid onset (seconds-mins) of focal CNS signs and symptoms
what are the important stroke mimics
7 S
Seizures Syncope Sugar (hypo/hyperglycaemia) SOL (tumours/brain abscess/SDH) Severe migraine Sepsis Si-chological/psychology
what are causes of strokes
- small vessel occlusions/cerebral microangiopathy
- thrombosis in situ
- cardiac emboli (AF, endocarditis, MI)
- Atherothromboembolism
- CNS bleeds (BP increase, trauma, aneurysm rupture, anticoagulation, thrombolysis)
how is the cerebral circulation split (anterior and posterior)
anterior - 80% of cerebral flow; middle and anterior cerebral artery
posterior - 20% of cerebral flow; vertebra-basilar system and posterior cerebral artery
Sx of acute stroke
- sudden onset
- focal language problems = aphasia/dysphasia/slurred speech
- visual disturbances = hemianopia/diplopia
- loss of coordination (particularly in loss of posterior circulation)
- headache
what does the symptoms of a stroke depend on
location of the bleed
although unreliable, what signs/Sx point to a haemorrhagic or ischaemic stroke
bleed = meningism, severe headache, coma
ischaemic = carotid bruit, AF, past TIA, IHD
what are the main locations of an infarct in the brain
Cerebral infarct
Brainstem infarct
Lacunar infarct
what is a lacunar infarct
most common type of stroke
results from occlusion of small penetrating arteries
supplies basal ganglia, internal capsule, thalamus and pons
what are Sx suggestive of a cerebral infarct
- contralateral sensory loss or hemiplegia
- initially flaccid (floppy limbs)
- dysphagia
- homonymous hemianopia
- visuo-spatial deficit
what are Sx suggestive of brainstem infarcts
- quadriplegia
- disturbance of gaze and vision
- locked-in syndrome
what are Sx of lacunar infarcts
- No visual field defect
- No new higher cortical or brainstem dysfunction
- Pure motor hemiparesis, or pure sensory deficit of one side of the body, or sensorimotor hemiparesis or ataxic hemiparesis
(dysarthric clumsy hand syndrome or ipsilateral ataxia with crural hemiparesis)
what is intact in lacunar infarcts
cognition/consciousness
except in a thalamic stroke
what is a watershed stroke
watershed zone = between 2 vascular beds where supply is most tenuous
occur at the border between cerebral vascular territories
what is CADASIL
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarct & Leucoencephalopathy
why is CADASIL important and what gene is affected
most common genetic cause of stroke
NOTCH3 gene mutation
how does CADASIL present
40 y/o with migraine, TIA, mood disorders, dementia +/- pseudo bulbar palsy
what will a stroke in the dominant hemisphere cause
normally left hemisphere; think how most people are right handed
language problems
what will a stroke in the non dominant hemisphere causes
spacial awareness problems
what is the first line Ix for suspected stroke and why
Non contrast CT
MRI more detailed but takes too long
what is an MRI useful for
identify old lesions and lesions of non-vascular origin
identify new ischemic lesions
identify bleeds and micro bleeds
what is an early CT sign of a stroke (of the Middle Cerebral artery)
Loss of the insular ribbon sign
- loss of definition of the gray-white interface in the lateral margin of the insular cortex
what are Sx of a POSTERIOR circulation stroke
Cranial nerve palsy Unilateral or bilateral motor or sensory deficit Disorder of conjugate eye movements Cerebellar dysfunction Homonymous hemianopia Cortical blindness
