Stroke Flashcards
What is a stroke?
Clinical syndrome
Caused by sudden interruption of blood supply to the brain
Leads to rapidly developing focal or global neurological disturbances lasting > 24 hours
What is a TIA?
A “mini-stroke”
Very similar symptoms to stroke but last < 24 hours
Most resolve within 1-2 hours
What are the different kinds of stroke?
Ischaemic (85%)
Haemorrhagic (15%)
- 10% strokes due to primary haemorrhage
- 5% due to SAH
What is the epidemiology of stroke (overall)?
- The first episode of stroke affects approximately 230 in 100,000 people per year in the UK
- > 80,000 people in England and Wales are admitted to hospital with acute stroke each year
What is the epidemiology of TIA?
Incidence of the first episode of TIA = ~ 50 in 100,000 people in the UK annually
Name rarer causes of strokes
Cerebral venous thrombosis - commonly seen in pts with prothrombic tendency (e.g., pregnancy, infection, inherited thrombophilia, dehydration, malignancy, primary intercranial HTN)
Carotid artery dissection
What is the pathophysiology of an ischaemic stroke?
- Occlusion of an intracranial vessel → reduced blood flow to the brain regions supplied by the vessel
- Leads to decreased oxygen supply and infarction in that region
- Focal cerebral infarction occurs via two distinct pathways
1. necrotic pathway with a rapid cytoskeletal breakdown
2. apoptotic pathway where ischaemia leads to necrosis and cells become programmed to die, leading to cellular depolarization and free radicals production, causing disruption in the vital functioning of the cells
How quickly do brain tissues die when cerebral blood flow is reduced to 0?
4-10 minutes
What flow value causes brain tissue infarction in an hour?
< 16-18ml/100g tissue per min
What flow value causes brain tissue ischaemia without infarction?
< 20 ml/100g tissue per min causes ischaemia without infarction unless prolonged for several hours
What is the aetiology of an ischaemic stroke?
*Thrombotic (includes lacunar strokes and large vessels occlusions) = atherosclerosis
*Embolic = atrial fibrillation (most common) - also in pts with valvular defect and endocarditis
What is the aetiology of a haemorrhagic stroke?
- Intracranial haemorrhages = uncontrolled HTN (most common)
- Subarachnoid haemorrhages - may occur as a result of AV malformations, berry aneurysms (which occur more commonly in patients with autosomal-dominant polycystic kidney disease) and cerebral angiomas
What is the pathophysiology of a haemorrhagic stroke?
- Spontaneous rupture of small, penetrating arteries deep inside the brain causes disturbance of white matter and neuronal activities within the brain
- Haemorrhagic collections act as mass lesions, causing compression and raised pressure leading to neurological deficits
What is the pathophysiology of TIA?
Acute occlusion of an intracranial vessel
↓
↓blood flow to the brain region supplied by the vessel
↓
decreased oxygen supply and infarction in that region
↓
blood flow returns to normal within 24 hours = resolution of symptoms
What are symptoms of stroke (in general)?
Headache (very sudden - reaches max intensity within 5 mins in SAH)
Slurred speech
Facial weakness
Facial/neck pain
Weak arms and legs (often sudden)
Altered taste and smell
Loss of vision
Urinary incontinence
Confusion/altered level of consciousness/syncope
Impaired pain/temperature sense
Cranial nerve deficit (e.g., Horner syndrome)
What are symptoms of a left hemisphere stroke?
- aphasia
- right-sided sensory loss
- right-sided hemiparesis
- right-sided visual field defect
- dysarthria
- difficulty in calculation
- difficulty writing
What are symptoms of a right hemisphere stroke?
- left-sided sensory loss
- left-sided hemiparesis
- left-sided gaze disturbances
- aphasia
- dysarthria
- spatial disorientation
What is the most commonly used classification system for ischaemic stroke? What does it include?
Bamford classification (a.k.a. Oxford classification system) - categorises strokes based on the initial presenting symptoms and clinical signs
Includes :
*Total anterior circulation stroke (TACS)
*Partial anterior circulation stroke (PACS)
*Posterior circulation syndrome (POCS)
*Lacunar stroke (LACS)
Name the Posterior circulation syndromes (POCs) signs
- cranial nerve impairment
- unilateral or bilateral motor or sensory deficit
- disorder of conjugate eye movement
- cerebellar dysfunction
- homonymous hemianopia (with macular sparing)
- cortical blindness
Name the Total anterior circulation syndromes (TACSs) signs
- hemiplegia and homonymous hemianopia contralateral to the lesion
- aphasia or visuospatial disturbance
- sensory deficit contralateral to the lesion
Name the Partial anterior circulation syndromes (PACSs) signs
Two of the following need to be present for PACS diagnosis
*unilateral weakness (and/or sensory deficit) of the face, arm and leg
*homonymous hemianopia
*higher cerebral dysfunction (dysphasia, visuospatial disorder)
N.B. higher cerebral dysfunction alone is also classified as PACS
What is a lacunar stroke?
Subcortical stroke
Occurs secondary to small vessel disease
No loss of higher cerebral functions (e.g., dysphasia)
Name the Lacunar stroke (LACS) signs
One of the following need to be present for a diagnosis of LACS
- pure sensory stroke
- pure motor stroke
- sensori-motor stroke
- ataxic hemiparesis
What investigations can be done a person with suspected stroke?
Bedside
-ECG (esp. looking for atrial fibrillation)
Bloods
-Baseline (FBCs, U+Es, LFTs, inflammatory markers)
-Coagulation profile
-Blood glucose
Imaging
-CT head – initial investigation of choice
What are the lifestyle advice in managing a stroke?
Lifestyle advice
-smoking cessation
-balanced diet
-increased exercise
-reduction of ETOH consumption
What is the pharmacological treatment of an ischaemic stroke?
Consider thrombolysis if the patient presents to hospital within <4.5 hours of symptoms onset:
- Alteplase – drug of choice
- Start aspirin 24 hours after thrombolysis
Consider thrombectomy with IV thrombolysis if presenting within 6 hours of symptom onset
If thrombolysis is not carried out:
- start aspirin 300mg orally if no dysphagia (or rectally/enterally if dysphagia is present) as a stat dose and continue this dose for 2 weeks
Make sure the patient is started in a PPI
Follow up at 2 weeks and start long term clopidogrel 75mg daily as maintenance
What drug can be offered instead as maintenance if clopidogrel is not tolerated?
- Aspirin 75mg OD with modified release dipyridamole 200mg BD can be used if clopidogrel is not tolerated
- If both clopidogrel and modified release dipyridamole are contraindicated or not tolerated, offer aspirin 75mg OD
- If both clopidogrel and aspirin are contraindicated or not tolerated, offer modified release dipyridamole 200mg BD
What is the pharmacological Mx of a haemorrhagic stroke?
- Control high BP (SBP) – BP should be rapidly lowered if:
- present within 6 hours of onset and SMP between 150-220 mmHg
- present beyond 6 hours of onset and SBP > 220 mmHg
- Aim for SBP target of 130-140mmHg within 1 hour of starting treatment and maintain this for at least 7 days
- Do not offer rapid BP lowering to people who:
have an underlying structural cause (e.g., tumour, AVM or aneurysm)
have a GCS < 6
are going to have early neurosurgery to evacuate the haematoma
have a massive haematoma with poor expected prognosis
Which subgroup of patients with a haemorrhagic stroke should be started on medical Tx initially and not surgical?
- a large haemorrhage and significant comorbidities
- small, deep haemorrhages
- posterior fossa haemorrhage
- lobar haemorrhage without either hydrocephalus or rapid neurological deterioration
- a GCS < 8 (unless due to hydrocephalus)
How should patients with TIA be managed?
For people with TIA within the last week
* Give aspirin as a 300mg loading dose (and then continued for 2 weeks)
- If the patient is already taking aspirin, the dose should be continued
- A PPI can be added if required
- If the aspirin is contraindicated, the patient should be discussed with a specialist team urgently
* Refer them to specialist stoke physician to be seen within 24 hours
- If the patient has a Hx of a bleeding disorder, or is on an anticoagulant they must be admitted and have an urgent CT scan to exclude haemorrhage
If the patient had a TIA > 1 week ago:
* Specialist review should be arranged within 7 days
How should patients with >1 TIA in a week be managed?
Patients who have had > 1 TIA in a week (crescendo TIA), have ongoing neurological symptoms, has severe cardiac stenosis or suspected cardio-embolic causes = URGENT ADMISSION
Describe the ongoing Mx of TIA
- Continue aspirin for 2 weeks
- Change to clopidogrel 75mg after 2 weeks
- A statin e.g., simvastatin 40 mg should also be started immediately and continued long-term
- All patients with TIA and their carers of family members should be given advice regarding signs and symptoms of TIA & stroke and ask them to call 999 if symptoms recur
What are the criteria for having a decompressive hemicraniectomy?
- clinical deficits that suggests infarction in the territory of the middle cerebral artery, with a score > 15 on the NIHSS
- ↓ level of consciousness, with a score of ≥1 on item 1a of the NIHSS
- signs on CT of an infarct of at least 50% at the middle cerebral artery territory
o with or without additional infarction in the territory of the anterior or posterior cerebral artery on the same side or
o with infarct volume > 145cm3, as shown on diffusion-weighted MRI scan
What are conjugate eye movements?
Conjugate eye movements are those that preserve the angular relationship between the right and left eyes.
For example, when you move both eyes left and then right, a conjugate movement is made
Source: http://www.yorku.ca/eye/eyemove.htm#:~:text=Conjugate%20eye%20movements%20are%20those,fall%20into%20the%20conjugate%20category.
What is visuospatial dysfunction?
Someone with visuospatial problems may find it hard to interpret what they see and act appropriately.
Their eyes may be perfectly able, but their brain is not able to make sense of the information their eyes are taking in
Hence they might find it difficult to work out where things are or to judge how quickly something or someone is moving
https://mstrust.org.uk/a-z/visuospatial-problems
