Stroke Flashcards
What is a stroke?
Represents a sudden interruption in the vascular supply of the brain.
Remember that neural tissue is completely dependent on aerobic metabolism so any problem with oxygen supply can quickly lead to irreversible damage.
What are the 2 types of stroke?
- ischaemic
2. haemorrhagic
Ischemic stroke
‘Blockage’ in the blood vessel stops blood flow (85% of cases)
Ischemic stroke risk factors
- Age, hypertension
- smoking
- hyperlipidaemia
- diabetes mellitus
- Cardio embolism - atrial fibrillation
What are the 2 sub-types of ischemic stroke?
- Thrombotic stroke
2. Embolic stroke
Thrombotic ischemic stroke
Thrombosis from large vessels e.g. carotid
Embolic ischemic stroke
Usually a blood clot but fat, air or clumps of bacteria may act as an embolus
Atrial fibrillation is an important cause of emboli forming in the heart
Hemorrhagic stroke
Blood vessel ‘bursts’ leading to reduction in blood flow (15% of cases)
Sub-types of Hemorrhagic stroke
- Intracerebral haemorrhage
2. Subarachnoid haemorrhage
Risk factors for Hemorrhagic stroke
>
age hypertension arteriovenous malformation anticoagulation therapy
The FAST-screening tool
Tool used by the public for recognition of stroke
> (Face/Arms/Speech/Time)
ROSIER
A variant of FAST called the ROSIER (recognition of stroke in emergency room) score is useful for medical professionals in the emergency department to differentiate from stroke mimetics.
Brainstem infarction symptoms
May result in more severe symptoms including quadriplegia and lock-in-syndrome
Cerebral hemisphere infarcts symptoms
- contralateral hemiplegia
- contralateral sensory loss
- homonymous hemianopia
- dysphasia (language impairment)
Investigations for stroke
- CT
* MRI
What are the 2 options for management of ischemic stroke?
- Thrombolysis (IV Alteplase)
* Thrombectomy
What is the criteria for being able to use thrombolysis for the management of ischemic stroke?
- Patients present with 4.5 hours of onset of stroke symptoms
- Patient has not had a previous intracranial haemorrhage, uncontrolled hypertension, pregnant etc
- Thrombolysis can be started IF haemorrhagic stroke has been excluded by appropriate imaging techniques such as CT scan.
Before thrombolysis can be given to a ischemic stroke patient, hemorrhagic stroke has to be excluded by imaging; what drug is given after the H. stroke has been excluded?
Once haemorrhagic stroke has been excluded patients should be given aspirin 300mg as soon as possible and antiplatelet therapy should be continued.
When should thromboectomy be given to ischemic stroke patients?
Offer after 4.5 hours to people who have:
- acute ischaemic stroke and
- confirmed occlusion of the proximal anterior circulation demonstrated by computed tomographic angiography (CTA) or magnetic resonance angiography (MRA)
When can thromboectomy be given between 6 and 24 hours as the time window for thromboectomy is only up to 6 hours?
Offer thrombectomy as soon as possible to people who were last known to be well between 6 hours and 24 hours previously (including wake-up strokes):
- who have acute ischaemic stroke and confirmed occlusion of the proximal anterior circulation demonstrated by CTA or MRA and
- if there is the potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume
What is the time window for thrombolysis in ischemic stroke patients?
Needs to be given within four and a half hours
What is the time window for thromboectomy in ischemic stroke patients?
4.5 to 6 hours
What drug should be given to all ischemic stroke patients asap who have had a intracerebral haemorrhage excluded by imaging?
- aspirin 300 mg orally if they do not have dysphagia or
2. aspirin 300 mg rectally or by enteral tube if they do have dysphagia.
How long should aspirin be continued in ischemic stroke patients?
Continue aspirin daily 300 mg until 2 weeks after the onset of stroke symptoms, at which time start definitive long-term antithrombotic treatment.
Start people on long-term treatment earlier if they are being discharged before 2 weeks.
TIA
Stroke symptoms last less than 24 hours although in the vast majority of cases the duration is much shorter, typically 1 hour or so.
Management for TIA
Give aspirin 300 mg immediately, unless contraindicated e.g. the patient has a bleeding disorder or is taking an anticoagulant (needs immediate admission for imaging to exclude a haemorrhage)
Crescendo TIA
If the patient has had more than 1 TIA
Criteria for specialist outpatient stroke review of TIA
More than 1 TIA (‘crescendo TIA’) or has a suspected cardioembolic source or severe carotid stenosis:
> Admission or observation urgently
Suspected TIA in the last 7 days:
> arrange urgent assessment (within 24 hours)
Suspected TIA more than a week previously:
> refer for specialist assessment as soon as possible within 7 days
Management of hemorrhagic stroke
Anticoagulants and antithrombotic medications should be stopped to minimise further bleeding.
If a patient is anticoagulated this should be reversed as quickly as possible.
Vitamin K/Prothrombin complex for warfarin reversal
What is used for reversal of warfarin?
Vitamin K/Prothrombin complex for warfarin reversal
When should oxygen be administered in stroke?
Oxygen saturation drops below 95%.
What is the systolic blood pressure targets in stroke management?
Offer if they have a systolic blood pressure between 150 and 220 mmHg.
Aim for a systolic blood pressure target of 130 to 140 mmHg within 1 hour of starting treatment and maintain this blood pressure for at least 7 days.
When should anti-hypertensive therapy be given in stroke management?
Patients with acute intracerebral haemorrhage
Offer if they have a systolic blood pressure between 150 and 220 mmHg.
Anterior cerebral artery
Supplies most midline portions of the frontal lobes and superior medial parietal lobes of the brain.
Associated symptoms anterior cerebral artery occlusion
Contralateral hemiparesis and sensory loss, lower extremity > upper
Disinhibition and speech perseveration
Primitive reflexes (eg, grasping, sucking reflexes)
Altered mental status
Impaired judgment
Middle cerebral artery
Supply the majority of the lateral surface of the hemisphere, except the superior portion of the parietal lobe (via the ACA) and the inferior portion of the temporal lobe and occipital lobe (via the PCA).
In addition, they supply part of the internal capsule and basal ganglia.
Associated symptoms of middle cerebral artery occlusion
Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Associated symptoms posterior cerebral artery occlusion
Contralateral homonymous hemianopia with macular sparing
Visual agnosia
Posterior cerebral artery
Supply the posterior medial parietal lobe and the splenium of the corpus callosum, inferior and medial part of the temporal lobe including the hippocampal formation, and the medial and inferior surfaces of the occipital lobe.
Weber’s syndrome symptoms
Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity
Symptoms of anterior inferior cerebellar artery (lateral pontine syndrome) lesions
Symptoms are similar to Wallenberg’s, but:
Ipsilateral: facial paralysis and deafness
Symptoms of Retinal/ophthalmic artery lesions
Amaurosis fugax - a painless temporary loss of vision in one or both eyes.
What syndrome is caused by Basilar artery stroke (brain stem infraction)
‘Locked-in’ syndrome
Wallenberg syndrome
Lateral medullary infarction caused by an occlusion of the posterior inferior cerebellar artery (PICA) or the vertebral artery.
What is Weber’s syndrome?
Ipsilateral third nerve palsy with contralateral hemiplegia - caused by midbrain strokes - weber syndrome is also known as midbrain stroke
