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
in relation to lacunar strokes, how many areas are affected often
- At least 2 of the 3 areas (face, arm, leg) should be involved in its entity
what is the most commonly affected territory in cerebral infarctions
middle cerebral artery
Sx of a middle cerebral artery infarctions
contralateral hemiparesis
contralateral hemisensory loss
hemianopia
aphasia: if the dominant hemisphere
neglect: non-dominant hemisphere
what does an Anterior cerebral artery (ACA) infarct present with
dysarthria, aphasia
unilateral contralateral motor weakness (leg/shoulder > arm/hand/face)
minimal sensory changes (two-point discrimination - leg/shoulder > arm/hand/face)
left limb apraxia
urinary incontinence
how does an Anterior inferior cerebellar artery (AICA) infarct present
vertigo
ataxia
peripheral facial palsy
hypoacusis
how does a basilar artery occlusion present
sudden death/LOC
‘locked in syndrome’
what is Weber Syndrome
midbrain stroke syndrome that involves the fascicles of the oculomotor nerve
what are Sx of Weber Syndrome
ipsilateral CN III palsy and contralateral hemiplegia or hemiparesis.
what arteries does Weber Syndrome affect
branches of the posterior cerebral artery that supply the midbrain
what are Sx of occlusion of the retinal/ophthalmic artery
amaurosis fugax
in regards to the Tx of stroke, what should be considered if the patient is seen within 4.5 hours
1 - intravenous or intra-arterial thrombolysis (e.g. streptokinase, rtPA)
= 0.9 mg/Kg for Thrombolysis
2 - mechanical thrombectomy
what are absolute contraindications for thrombolysis
- recent severe bleeding
- Hx of intracranial bleeding
- Sx suggestive of SAH
- Known hemorrhagic problems
- recent major surgery - 14 days
- blood pressure more than 185/110 ever after treatment with beta blocker
what are relative contraindications for thrombolysis
- on warfarin (unless INR > 1.6)
- any Hx of CNS damage (neoplasms etc)
- recent traumatic external heart massage
- seizure at onset of stroke
- major surgery or significant trauma in past 3 months
what is given if a patient presents after 4.5 hours or cannot have thrombolysis
aspirin = 300 mg orally once daily
what cardiac arrhythmia is a big risk factor for stroke
AF
what should be stopped in a hemorrhagic stroke
statins and anticoagulants
what is the definition of a TIA
stroke symptoms and signs that resolve within 24 hours
most TIAs resolve fully within 30-60 minutes however
what Ix should TIA patients get
Carotid doppler
