Stroke Flashcards
What are the causes of stroke?
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What are the differentials for stroke?
Differential diagnosis
M8S:
Migraine
Sugar: hypoglycaemia.
Seizures, especially Todd’s palsy.
Sepsis, encephalitis.
Syncope
SDH
Space occupying lesion.
OldStrokes with intercurrent illness.
Somatisation
What are the risk factors for stroke
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What Investigations are done in an Acute stroke
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What is the acute management of Stroke?
Acute management of ischaemic stroke
Patients should be approached in the DR ABCDE manner.
Airway protection (in patients presenting with depressed consciousness) and aspiration precautions (in patients presenting with swallowing impairment) are very important.
Subsequent stroke management depends on whether the stroke is ischaemic or haemorrhagic. CT head should be performed on arrival to the emergency department to distinguish ischaemic from haemorrhagic stroke.
Alteplase (tissue plasminogen activator) is indicated in patients presenting within 4.5 hours of symptom onset and with no contraindications to thrombolysis (e.g. recent head trauma, GI or intracranial haemorrhage, recent surgery, acceptable BP, platelet count, and INR).
Mechanical Thrombectomy can be performed in patients with anterior circulation strokes within 6 hours of symptom onset, provided that they have a good baseline functional status and lack of significant early infarction on initial CT scan. Mechanical Thrombectomy can also be performed in posterior circulation strokes up to 12 hours after onset.
If hyper-acute treatments are not offered, patients should receive aspirin 300 mg orally once daily for two weeks. If hyper-acute treatments are offered, aspirin is usually started 24 hours after the treatment following a repeat CT Head that excludes any new haemorrhagic stroke.
What is the chronic management of stroke?
Stroke investigations (post-acute)
Investigations in the post-acute phase aim to further define the cause of the stroke and to quantify vascular risk factors.
Further investigations to determine the cause of the stroke include, for example:
In ischaemic stroke: carotid ultrasound (to identify critical carotid artery stenosis), CT/MR angiography (to identify intracranial and extracranial stenosis), and echocardiogram (if a cardio-embolic source is suspected). In young patients further investigation e.g. a vasculitis screen or thrombophilia screen may be necessary.
In haemorrhagic stroke: serum toxicology screen (sympathomimetic drugs e.g. cocaine are a strong risk factor for haemorrhagic stroke).
Further investigations to quantify vascular risk factors include: serum glucose (all patients with stroke should be screened for diabetes with a fasting plasma glucose or oral glucose tolerance test), serum lipids (to check for raised total cholesterol/LDL cholesterol).
Stroke management (chronic)
The key steps in secondary stroke prevention can be remembered by the mnemonic HALTSS:
Hypertension: studies show there is no benefit in lowering the blood pressure acutely (as this may impair cerebral perfusion) unless there is malignant hypertension (systolic blood pressure >180 mmHg). Anti-hypertensive therapy should, however, be initiated 2 weeks post-stroke.
Antiplatelet therapy: patients should be administered Clopidogrel 75 mg once daily for long-term antiplatelet therapy. In patients with ischaemic stroke secondary to atrial fibrillation, however, warfarin (target INR 2-3. or a direct oral anticoagulant (such as Rivaroxaban or Apixiban) is initiated 2 weeks post-stroke.
Lipid-lowering therapy: patients should be prescribed high dose atorvastatin 20-80 mg once nightly (irrespective of cholesterol level this lowers the risk of repeat stroke).
Tobacco: offer smoking cessation support.
Sugar: patients should be screened for diabetes and managed appropriately.
Surgery: patients with ipsilateral carotid artery stenosis more than 50% should be referred for carotid endarterectomy.
Rehabilitation and supportive management will include an MDT approach with involvement of physiotherapy, occupational therapy, speech and language therapy, and neurorehabiliation.
What is the nihss SCORE?
The NIH Stroke Scale (NIHSS) is a scoring system out of 42, which has been designed as a predictive score of clinical outcome in stroke.
This scoring system is completed on initial assessment of a patient with suspected stroke. It is important for the consideration of thrombolysis and clinical outcome.
A score < 4 is associated with a good clinical outcome. A high score (> 22) indicates a significant proportion of the brain is affected by ischaemia, and as such, there is higher risk of cerebral haemorrhage with thrombolysis. A score ≥ 26 is often considered a contraindication to thrombolysis.
Contraindications for thrombolysis
Contraindications to thrombolysis:
Absolute
- Previous intracranial haemorrhage
- Seizure at onset of stroke
- Intracranial neoplasm
- Suspected subarachnoid haemorrhage
- Stroke or traumatic brain injury in preceding 3 months
- Lumbar puncture in preceding 7 days
- Gastrointestinal haemorrhage in preceding 3 weeks
- Active bleeding
- Pregnancy
- Oesophageal varices
- Uncontrolled hypertension >200/120mmHg
relative
- Concurrent anticoagulation (INR >1.7)
- Haemorrhagic diathesis
- Active diabetic haemorrhagic retinopathy
- Suspected intracardiac thrombus
- Major surgery / trauma in the preceding 2 weeks
When is a thrombectomy done?
Mechanical thrombectomy is an exciting new treatment option for patients with an acute ischaemic stroke. NICE incorporated recommendations into their 2019 guidelines. It is important to remember the significant resources and senior personnel to provide such a service 24 hours a day. NICE recommend that all decisions about thrombectomy take into account a patient’s overall clinical status:
NICE recommend a pre-stroke functional status of less than 3 on the modified Rankin scale and a score of more than 5 on the National Institutes of Health Stroke Scale (NIHSS)
Offer thrombectomy as soon as possible and within 6 hours of symptom onset, together with intravenous thrombolysis (if within 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)
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):
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
Consider thrombectomy together with intravenous thrombolysis (if within 4.5 hours) as soon as possible for people last known to be well up to 24 hours previously (including wake-up strokes):
who have acute ischaemic stroke and confirmed occlusion of the proximal posterior circulation (that is, basilar or posterior cerebral artery) 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 advice would you give them regarding driving?
stroke or TIA: 1 month off driving, may not need to inform DVLA if no residual neurological deficit
multiple TIAs over short period of times: 3 months off driving and inform DVLA
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chronic neurological disorders e.g. multiple sclerosis, motor neuron disease: DVLA should be informed, complete PK1 form (application for driving licence holders state of health)
When is carotid endartectomy done?
patients with ipsilateral carotid artery stenosis more than 50% should be referred for carotid endarterectomy.
How many recover after stroke?
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Scoring systems used in stroke?
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Cardiac causes of stroke
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Mechanism of anti platelet agents?
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Whats the CHADSVASC score?
NICE categorise CHA2DS2-VASc scores as:
Low risk - 0 (if a woman has no other risk factors gender is no longer significant).
Intermediate risk - 1
High risk ≥ 2 - anticoagulation.
NICE CG 180 recommend anticoagulation in all patients with a score of 2 or more. It should be considered in men with a score of 1. In women with a score of 1 due to gender, NICE do no consider this an indication for treatment.
What is the HASBLED score
The HAS-BLED score helps the identification of those at risk of significant bleeding on anticoagulation therapy.
A point is given for each of the following factors shown. HAS-BLED can be used to remember the factors though this does combine drugs and alcohol, as well as abnormal liver function and abnormal renal function to make it fit. The prescence of each of these factors scores an individual point.
What are the different types of AF
Atrial fibrillation (AF) refers to irregular atrial contraction, caused by chaotic impulses. AF is increasingly common, NHS studies indicate a prevalence of 1-2% in the UK. It is a major cause of morbidity, in particular stroke, which is largely preventable with appropriate anticoagulation.
AF can be classified as paroxysmal, persistent or permanent:
Paroxysmal
Recurrent (more than 1 episode ≥30 seconds in duration).
Terminates spontaneously within 7 days (usually within 48 hours of presentation).
Persistent
Lasts longer than 7 days or requires termination by pharmacological / electrical cardioversion.
Permanent
Refractory to cardioversion.
Sinus rhythm cannot be restored or maintained.
AF is accepted as a final rhythm.
What can cause AF?
Aetiology
A large number of conditions may predispose too AF.
Cardiac
Hypertension IHD Valvular disease (RHD) Cardiomyopathy Non-cardiac
Respiratory COPD Pneumonia Pulmonary embolism Pleural effusion Lung cancer Endocrine Thyrotoxicosis Diabetes mellitus Infection Electrolyte disturbances Drugs Bronchodilators Thyroxine Lifestyle
Alcohol
Caffeine (contribution is debated, there is no evidence that at normal levels of consumption caffeine causes AF)
athophysiology
Despite the range of risk factors and causative conditions, common changes to the electrophysiology of the heart may occur.
Atrial myocardium
Atrial myocardium has a number of interesting electrophysiological properties. It possesses a short action potential with a refractory period that reduces with an increasing rate.
These properties permit rapid contraction.
Generation of arrhythmia
As mentioned, AF is caused by disruption of the electrophysiology in the atrial myocardium. Many mechanisms have been proposed with varying degrees of evidence to support their existence. Most likely, they occur simultaneously.
Two of the most commonly discussed mechanisms are:
Multiple wavelets - proposes that wavefronts (spontaneous waves of excitation) become fragmented resulting in multiple daughter wavelets.
Autonomic foci - these foci, located primarily in the pulmonary veins, act to initiate AF.
Ultimately, the physiological sinoatrial node rhythm is superseded by these rapid and chaotic impulses.
What investigations and treatment options are available for AF?
anagement of AF may be achieved with rate or rhythm control.
Underlying causes should be identified and treated. Patients may be anticoagulated to reduce the risk of thrombo-embolic events.
Rate control
Most common type of management. Aimed at controlling rapid heart rate.
First line therapies:
Beta blockers (e.g. metoprolol) Rate-limiting calcium channel blockers (e.g. verapamil). Other therapies:
Digoxin monotherapy - may be used in sedentary patients (in active patients sympathetic action may easily overcome the effects of digoxin).
Sotalol - should only be prescribed by a cardiologist due to life-threatening side effects.
Rhythm control
Cardioversion is aimed at reverting the heart back to a normal (sinus) rhythm.
Decision made by specialists, may be indicated when:
New onset
Identifiable reversible cause.
Heart failure (caused by or exacerbated by AF).
There are two forms of cardioversion:
Electrical - typically indicated in AF that has been present > 48hrs.
Pharmacological - amiodarone, sotalol.
In new-onset AF establishing time of onset is important. Firstly, ventricular rate should be appropriately controlled. If onset < 48hrs, immediate cardioversion can take place. If > 48hrs or timing is uncertain, anticoagulation (for at least three weeks) is required before cardioversion. This is due to potential thrombus generation in the atrial appendage.
Anticoagulation
Anticoagulation may take two main forms:
Vitamin K antagonists (e.g. warfarin): has been the mainstay for many years. Regular INR measurements required.
Direct-acting oral anticoagulants (DOACs): newer agents such as Rivaroxaban (direct Xa inhibitor) and Dabigatran (direct thrombin inhibitor).
If the above are contraindicated dual anti-platelet therapy (aspirin and clopidogrel) may be used. Aspirin or clopidogrel monotherapy is no longer advised.
Ablation therapy
Catheter and surgical ablation therapy offers an additional treatment option. NICE recommends its use when drug treatment has failed. The potential risks and benefits should be discussed with the patient. It is a complex procedure requiring mapping of circuits and can fail.
What are the complications of AF
notable complications include
cardiac tamponade
stroke
pulmonary valve stenosis
success rate
around 50% of patients experience an early recurrence (within 3 months) of AF that often resolves spontaneously
longer term, after 3 years, around 55% of patients who’ve had a single procedure remain in sinus rhythm. Of patient who’ve undergone multiple procedures around 80% are in sinus rhythm
How can stroke’s be classified?
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What are the cerebellar stroke syndromes and how do they present?
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