stroke Flashcards
what are the different types of stroke ?
Ischemic stroke: cerebral infarction due to insufficient cerebral blood flow (most common 85 percent)
- Embolism
- thrombosis - atherosclerotic plaque rupture
- thromboembolism
- Systemic hypo-perfusion: blood supply to the entire brain is reduced secondary to systemic hypotension (e.g. cardiac arrest)
- Cerebral venous sinus thrombosis: blood clots form in the veins that drain the brain, resulting in venous congestion and tissue hypoxia
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Hemorrhagic stroke: cerebral infarction due to hemorrhage
- intracerebral hemorrhage ( subtypes - intraparenchymal / intraventricular)
- subarachnoid hemorrhage
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Transient ischemic attack: temporary, focal cerebral ischemia that results in neurologic deficits without acute infarction or permanent loss of function
what is the classification used for ischemic stroke ?
Bamford classification (categorises stroke based on the initial presenting symptoms and clinical signs. This system does not require imaging to classify the stroke, instead, it is based on clinical findings alone)
signs worst at onset
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1) Total anterior circulation stroke (TACS)
large cortical stroke - affecting the areas of the brain supplied by both the middle and anterior cerebral arteries
middle cerebral artery is most commonly affected
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2) Partial anterior circulation stroke (PACS)
Partial anterior circulation stroke (PACS) is a less severe form of TACS, in which only part of the anterior circulation has been compromised
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Posterior circulation syndrome (POCS)
posterior circulation syndrome (POCS) involves damage to the area of the brain supplied by the posterior circulation (e.g. cerebellum and brainstem)
basilar artery (BA), formed by the left and right vertebral arteries, branches into a left and right posterior cerebral artery (PCA),
============= Lacunar stroke (LACS)
lacunar stroke (LACS) is a subcortical stroke that occurs secondary to small vessel disease. There is no loss of higher cerebral functions (e.g. dysphasia).
Lenticulostriate arteries
Occlusion is often caused by lipohyalinosis (hyaline arteriosclerosis) secondary to unmanaged hypertension
how can we diagnose Total anterior circulation stroke (TACS) in bamford classification
All three of the following need to be present for a diagnosis of a TACS
- Unilateral weakness (and/or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction (dysphasia, visuospatial disorder)
dysphasia = language disorder marked by deficiency in the generation of speech, and sometimes also in its comprehension
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middle cerebral artery - contralateral weakness and sensory loss mre marked in upper limb and lower half of face
rather than lower limbs
gaze deviation to side of infraction
contraletral homonymous hemianopia - WITHOUT macular sparing (MACULAR sparing -macular vision is preserved despite adjacent visual field defects )
aphasia - if in dominant hemisphere
Hemineglect t if in nondominant hemisphere (usually right MCA territory
a common and disabling condition following brain damage in which patients fail to be aware of items to one side of space
motor neglect -
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anterior cerebral artery
contralateral weakness and sensory loss in the LOWER limbs more marked than upper limbs
- abulia (disinterest and a slowed mental state)
- urinary incontinence
- dysarthria
muscles that are used to produce speech are damaged, paralyzed, or weakened
- transcortical motor aphasia (A type of aphasia characterized by a lack of fluency with intact comprehension and repetition)
how can we diagnose Partial anterior circulation stroke (PACS) in bamford classification
Two of the following need to be present for a diagnosis of a PACS:
Unilateral weakness (and/or sensory deficit) of the face, arm and leg
Homonymous hemianopia
Higher cerebral dysfunction (dysphasia, visuospatial disorder)
how do we diagnose Posterior circulation syndrome (POCS) in bamford classification
One of the following need to be present for a diagnosis of a POCS:
Cranial nerve palsy and a contralateral motor/sensory deficit
Bilateral motor/sensory deficit
Conjugate eye movement disorder (e.g. horizontal gaze palsy)
Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
Isolated homonymous hemianopia
Brainstem - Horner syndrome
Locked in syndrome = complete paralysis of voluntary muscles, except for those that control the eyes.
Top basilar syndrome sudden changes in the level of consciousness, confusion, amnesia, and visual symptoms (eg, hemianopia, cortical blindness, abnormal colour vision , also oculomotir abnormality - vertical gaze palsy Somnolence Hallucination Behaviour abnormality
how do we diagnose lacunar stroke in bamford classification ?
One of the following needs to be present for a diagnosis of a LACS:
Pure motor stroke (most common) : Contralateral hemiparesis of the face, arm, and leg
Pure sensory stroke:
Contralateral numbness and paresthesia of the face, arm, and leg
Sensori-motor stroke
Ataxic hemiparesis: Ipsilateral weakness with impaired coordination (e.g., ataxia, gait instability)
Dysarthria-clumsy hand syndrome : Contralateral facial and hand weakness with dysarthria
Hemiballismus: Contralateral, involuntary, large flinging movements of the arm or leg
what is the aetiology of stroke ?
increase age and male
lifestyle - smoking , alcohol , Combined pill
hypertension , diabetes , hypercholesterolemia
previous stroke
CARDIAC CAUSES - non-valvular atrial fib,
Prosthetic valves. • Acute myocardial infarct with large left ventricular wall motion abnormalities on echocardiography. • Patent foramen ovale/septal defects. • Cardiac surgery. • In- fective endocarditis
thrombophilia - polycethmia , APS (anti phos)
coagulopathy - warfarin , liver disease
vasculitis , SLE , homocysteinurea
Cardiac emboli : Atrial fibrillation!
endocarditis
how to diagnose stroke ?
Determine the time of onset of symptoms
time of stroke onset determines whether thrombolytic therapy is an option
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1) Noncontrast head CT (first-line imaging)
detection of ischemic changes that occur after 6–24 hours (cannot be used to reliably identify earlier ischemia)
INDICATED IN ALL PATIENTS suspected of having an acute stroke to rule out intracranial hemorrhage BEFORE administering thrombolytic therapy
ct angiography
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Diffusion-weighted MRI
- Allows identification of
ischemia earlier than a CT (within 3–30 minutes after onset) - Allows detection of hyperacute hemorrhage
Evaluates reversibility of ischemic injury
Perfusion-weighted imaging (PWI): visualizes areas of decreased perfusion
Perfusion-diffusion mismatch MRI:
allows identification of the penumbra (or “tissue-at-risk”)
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lab
initial serum glucose
coagulation parameteres - INR PTT
thrombocytopenia
ear vasculitis
ECG - atrial fib
echo - if embolic suspected
what is the acute management of stroke ?
A-E
2 large bore IV access
blood pressure - only treated if were is hypertension emergency - such as encephalopathy and aortic dissection
ideally aim for 185/110
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//check blood glucose//
-keep blood glucose 4-11mmol/l
hypoglycemic - intravenous (IV) bolus of dextrose 10% 2.5 mL/kg
hyperglycemia with subcutaneous insulin on a sliding scale
nill by mouth
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//urgent CT within 4 hours of onset - for thrombolysis to start //
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minimum neurological examination determine time of onset identify risk factors for ischemic GCS pupillary examination NIHSS score - severity score
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NBM until swallow assessment
order FBC , UE, LFT , crp , clotting
ECG - Cardiac monitoring (for at least 24 hours)
cardiac echo
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withhold aspirin/ warfarin / LMWH until CT confirm no bleed or hemorrhage
once haemorrhagic stroke is excluded
give aspirin 300mg PO/PR -continue for 2 weeks, then switch to long-term antithrombotic treatment
antithrobolytic agent
haemorrhage has been excluded, provided
the onset of symptoms was ≤4.5h ago
thrombolytic agent of choice is alteplase
always do CT 24hr post lysis to identify any bleeds
thrombectomy - large artery occlusion in the proximal anterioir circulation
admit to stroke unit
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if hemorrhagic
immediate neurosurgical
Blood pressure management in ICH: The optimal
If systolic BP is > 220 mm Hg,
promptly lower to 140–180 mm Hg, e.g., using nicardipine AND/OR labetalol
If systolic BP is 150–220 mm Hg and no contraindications to antihypertensive agents: Consider BP lowering on an individual basis in consultation with a specialist.
agents include:
ACE inhibitors, e.g., enalapril or ARBs
Furosemide
Anticoagulation reversal
Stop all anticoagulants and antiplatelet agents.
Administer reversal agents as soon as possible to patients with an INR > 1.4 to reduce the risk of hematoma expansion.
Vitamin K or PCC: to reverse the effects of warfarin
Protamine: to reverse the effects of heparin-based therapy
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swallow assessment - uses X-rays in real time (fluoroscopy) to film as you swallow. You’ll swallow a substance called barium that is mixed with liquid and food
carotid doppler
cardiac echo
why is blood glucose important in stroke and why do we have to check it and do Ct before thrombolysis can be administered ?
Blood glucose is often elevated in acute stroke, and higher admission glucose levels are associated with larger lesions, greater mortality and poorer functional outcome. In patients treated with thrombolysis, hyperglycemia is associated with an increased risk of hemorrhagic transformation of infarcts
or stroke mimic
Transient hypoglycemia is well known to produce a stroke-like picture with hemiplegia
Its a common occurrence in diabetic patients receiving pharmacologic treatment
which imaging method is most sensitive to an infract ?
diffuse weighted MRI is most sensitive to ague infarct but CT helps rule out primary hemorrhage
why should thrombolysis be started at 4.5hr or less after exclusion of haemorrhage ?
benefits of thrombolysis outweigh the risks in this window - BEST RESULTS ARE WITHIN 90 mins
what is the prevention techniques for stroke
preventing further strokes
control risk factors -primary prevention :
- treat hypertension
- DM
- hyperlipedemia
- quit smoking
- exercise
- lifelong anticoagulation in AF and prosthetic heart valves
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secondary prevention
anti platelet agents after stroke - 2 weeks of aspirin 300mg
switch to long term clopidogrel monotherapy
what score in afib ca be used to calculate risk of stroke in patients with AF ?
CHA2 DS2 VASC score
Offer anticoagulation in patients with a score of 2 or above.
Do not offer stroke prevention therapy in patients with AF if <65y and CHA2DS2VASC score is 0 for men or 1 for women
bleeding risk with anticoagulation therapy is using ?
HAS-BLED score
H- hypertension >160 A abnormal liver or renal function = 1/2 S sroke B bleeding tendency L abile inr E more than 65 yrs D drugs aspirin / NSAIDS , alcohol 1/2
out of 9
3 or more high risk iof bleeding = review oral anticogulants
usually to asses quality of afib care
