Stroke Flashcards
What does FAST stand for?
Face
Arms
Speech
Time
In acute stroke, how many neurons die per minute until blood flow is restored, on average?
1.9 million - TIME IS BRAIN
Why do we take patients to Stroke centres?
Acute stroke is an emergency: stroke centres are organised to patients can be assessed by specialists trained in delivering emergency stroke treatment immediately.
How is the NIHSS score calculated?
Level of consciousness:
- Alert (0)
- Not alert, arousable with minimal stimuation (1)
- Not alert, requires repeated stimulation to attend (2)
- Coma (3)
Patient knows month and own age:
- Answers both correctly (0)
- Answers one correctly (1)
- Both incorrect (2)
Patient opens and closes eyes on command:
- Obeys both correctly (0)
- Obeys one correctly (1)
- Both incorrect (2)
Best gaze:
- Normal (0)
- Partial gaze palsy (1)
- Forced deviation (2)
Visual field testing
- No visual field loss (0)
- Partial hemianopia (1)
- Complete hemianopia (2)
- Bilateral hemianopia (blind including cortical blindess) (3)
Facial paresis
- Normal symmetrical movement (0)
- Minor paralysis (1)
- Partial paralysis (2)
- Complete paralysis of one/both sides (3)
Motor function of EACH LIMB
- Normal (0)
- Drift (1)
- Some effort against gravity (2)
- No effort against gravity (3)
- No movement (4)
- Untestable* (0)
Limb ataxia
- None (0)
- One limb (1)
- Two limbs (2)
Pinprick sensation
- Normal (0)
- Mild to moderate decrease in sensation (1)
- Severe to total sensory loss (2)
Language
- No aphasia (0)
- Mild-moderate aphasia (1)
- Severe aphasia (2)
- No speech (3)
Dysarthria
- None (0)
- Mild-moderate slurring (1)
- Severe (2)
- Intubated etc (0)
Extinction and inattention
- Normal (0)
- Inattention/extinction to bilateral simulteanous stimulation in one sensory modality (1)
- Severe hemi-attention/hemi-inattention to more than one modality (2)
Total score is out of 10, tested both before and after treatment.
When can thrombolysis be given?
Within 4.5 hours of a clear onset of symptoms
What is the thrombolysis inclusion criteria?
Must say yes to all
- Symptoms of acute stroke
- Onset in last 4.5 hours
- Measurable deficit on NIHSS
- Absence of haemorrhage on CT scan
What is the thrombolysis exclusion criteria?
Must answer no to all
- Signs suggestive of subarachnoid haemorrhage
- Head trauma, brain/spinal surgery, stroke within 3 months
- Major surgery/ non-head trauma in the last 14 days
- History of any intracranial haemorrhage, cerebral aneurysm, or AVM
- GI, urinary, or gynae haemorrhage within last 21 days/evidence of active bleeding
- Known/confirmed aortic dissection
- Arterial puncture at non compressible site within 7 days
- Recent lumbar puncture in last 10 days
- Currently pregnant
- Systolic over 185 and/or diastolic over 110
- Known/suspected bacterial endocarditis
- Platelet count 1.4 on warfarin
- Heparin/newer oral anticoagulant within last 48 hours/ INR over 1.4 on warfarin
What are two recognised complications of thrombolysis in acute stroke?
- 6% risk of haemorrhage (2-3% considered major/life-threatening
- 7% risk of angioedema (risk increased by treatment with an ACE inhibitor
What is thrombolysis?
Breaks down the offending clot in stroke
- Ischaemic stroke
- Restores cerebral blood flow
- Minimise permanent damage/restore function
- Risk of cerebral haemorrhage
How is thrombolysis given?
0.9mg/kg Alteplase IV infusion over 1 hour
Monitor patient throughout for neurological or physiological changes
What needs to be done on admission when considering thrombolysis?
Ensure:
- Blood tests
- CT scan
- Specialist review
- Decision
- Administer treatment
Consider:
- Early specialist support
- Prompt CT scan
- Check obs
- Check weight
- Consider contraindications
Ask:
- Recent major surgery/bleeding
- Anticoagulants
- Recent strokes, including haemorrhagic
What is the strongest predictor of outcome in acute stroke?
Age and stroke severity
What are the two types of stroke and how often do they occur?
Ischaemic stroke: 8% of all strokes
Haemorrhagic stroke: 15% of all strokes
What type of stroke is TACS?
Total anterior circulation stroke
Occurs in the ACA/MCA
Diagnosis:
All three of the following
1. Unilateral weakness (and or sensory loss) of face, arm and leg
2. Homonymous hemianopia
3. Higher cerebral dysfunction (dysphasia, visuospatial disorder)
What type of stroke is PACS?
Partial anterior circulation stroke
Occurs in the MCA/ACA
Diagnosis:
2 of the following
1. Unilateral weakness (and or sensory loss) of face, arm and leg
2. Homonymous hemianopia
3. Higher cerebral dysfunction (dysphasia, visuospatial disorder)
What type of stroke is POCS?
Posterior circulation syndrome
Occurs in the posterior circulation
Diagnosis: 1 of the following 1. Cerebellar or brainstem syndrome 2. Loss of consciousness 3. Isolated homonymous hemianopia
What type of stroke is LACS?
Lacunar syndrome
Occurs subcortically due to small vessel disease
Diagnosis: 1 of the following 1. Unilateral weakness (and/or sensory deficit of face and arm, arm and leg of all 3) 2. Pure sensory stroke 3. Ataxic hemiparesis
What happens during the ischaemic cascade?
There is a lack of oxygen, so anaerobic respiration occurs.
Less ATP is produced as it is less effective than aerobic respiration.
When ATP-reliant Na+/Ca2+ ion transport pumps fail, intracellular calcium levels get too high, triggering the release of glutamate
This excites other neurons. They then bring in Ca2+ themselves, and more glutamate is released.
This is called EXCITOTOXICITY.
What is cytotoxic oedema?
When anaerobic respiration occurs in the brain, ATP-reliant Na+/K+ pumps fail.
Na+ builds up in the neurons as it is not pumped out.
Water in the ECF then rushes in due to the osmotic gradient to dilute Na+, causing oedema within the neurons.
How do you diagnose a transient ischaemic attack (TIA)?
Transient: Patient must have fully recovered before diagnosis is made (within 24 hours) If patient still has symptoms this would be a stroke
Ischaemic: Neurological symptoms need to fit with territory of artery - upper motor neurone signs, no isolated dizziness or memory loss
Attack: sudden onset, neurological symptoms have a sudden onset
What is a crescendo TIA?
A crescendo TIA refers to two or more episodes of TIA within a week
Requires urgent specialist evaluation
What are some common differentials for TIAs?
Syncope Atypical seizures Migraine Temporal arteritis Retinal haemorrhage or detachment Hypoglycaemia Labrynthine disorders associated with vertigo (such as BPPV)
What should a GP do with a patient with a suspected TIA, according to NICE guidance?
Refer urgently to a TIA clinic to be seen within 24 hours
Which investigations are performed in a TIA clinic?
- Height, weight, and BMI
- Blood glucose
- Blood ests including FBCC, U&Es. LFTs and lipids
- ECG
How is the CADVASC score used?
CHADVASC is used to calculate a patient’s stroke risk in patients with atrial fibrillation
It takes into account:
- Age
- Previous TIA/stroke
- Prrevious MI/PAD/aortic plaque
- Patient’s sex
- Diagnosed heart failure or left ventricular dysfucntion
- Hypertension
- Diabetes I/II
How should patients with carotid artery stenosis be treated?
If the patients is hound to have significant stenosis (50%+) then they should have an endarterectomy within 2 weeks
Patients with non-significant stenosis should be treated by controlling risk factors such as blood pressure, lifestyle advice, and hyperlipidaemia
In a patient with non-significant carotid stenosis, what would the management be?
Management of risk factors:
Start anticoagulation (warfarin) immediately in atrial fibrillation
(NOT antiplatelets like clopidogrel or aspirin)
Treat blood pressure
Treat cholesterol
Doing the above would reduce the patient’s stroke risk.
For how long after a TIA should a patient avoid driving?
At least 4 weeks
If the stroke symptoms are progressive, what is this suggestive of?
Intracranial haemorrhage
What is the management for an intracranial haemorrhage?
- Bloods: FBC, U&Es. LFTs
- Blood glucose
- INR
- CXR
Give prothrombin complex to reverse patient anticoagulation
Consider why patient may have had haemorrhage and tackle cause
What are some vascular risk factors for a TIA/stroke?
- Peripheral vascular disease
- Hypertension
- Diabetes
- Smoking
- Ischaemic heart disease
- Carotid stenosis
What are some thrombotic risk factors for a TIA/stroke?
- Polycythaemia
- Combined oral contraceptive pill
- Clotting disorders
- Atrial fibrillation
When do we give antiplatelets vs anticoagulation?
Antiplatelets are generally provided as prevention for future ischaemic strokes
However if a definite cardiac cause is identified, such as atrial fibrillation, anticoagulation is given.
What is the mechanism of action of aspirin?
It both reduces inflammation and fever, as well as thinning the blood
Aspirin binds irreversibly to COX, an enzyme involved in inflammation
COX normally acts upon arachidonic acid and converts it into prostaglandins
Aspirin prevents this and therefore reduces the formation of prostaglandins
This reduces inflammation
In clotting, COX also acts upon arachidonic acid, causing the release of thromboxane A2.
When aspirin prevents this, it prevents platelets from clumping together and causing clots.
