Stroke and TIA

Question 1

Causes of ischaemic stroke.

Answer 1

20% large artery atherosclerosis
20-25% cardiac disease
20-25% small artery disease
5% other causes (dissection, vasculitis, drug abuse)
25-30% cryptogenic stroke

Question 2

Which screening tool can be used to detect stroke in a person in the community?

Answer 2

FAST

Face
Arms
Speech
Time to call 999

Question 3

Which score can help to decide how likely it is that someone has had a stroke?

Answer 3

Rosier Scale Proforma

If equal to or less than 0, can only say stroke is unlikely but not excluded.

Question 4

How may a stroke be classified?

Answer 4

Using Bamford classification-

Total anterior circulation stroke
Partial anterior circulation stroke
Posterior circulation stroke
Lacunar stroke

Question 5

At what point might you see ischaemic changes on CT?

Answer 5

Not until around 4/5 hours after the stroke- when no longer eligible for thrombolysis.

MRI with DWI is much more sensitive for acute ischaemia (can detect within minutes of attack)

Question 6

Which choice of neuroimaging is recommended in acute stroke?

Answer 6

Emergency non-contrast CT of the head.

Question 7

For which patients should brain imaging be performed immediately/urgently?

Answer 7

If there are indications for thrombolysis
On anti-coagulation
Known bleeding risk
Depressed level of consciousness
Unexplained fluctuating/progressive symptoms
Papilloedema, neck stiffness or fever
Severe headaches at onset of symptoms

Question 8

How is eligibility for thrombolysis scored?

Answer 8

Must be YES-
Has symptoms of acute stroke
Measurable deficit on the NIHSS scale
Clear time of onset within 4.5 hours
Patient had a CT brain after onset to exclude haemorrhage.

Question 9

Contraindications for thrombolysis.

Answer 9

Hx of head trauma or stroke within last 3 months
Major surgery in last 2 weeks
Hx of intracranial haemorrhage
Hx suggestive of subarachnoid haemorrhage
Systolic BP>185
Diastolic BP>110
Has any hypertensive medication been used? Can it be improved?
Symptoms rapidly improving
Hx of GI or urinary tract haemorrhage in last 21 days
Arterial puncture at non-compressible site in last 7 days
Recent lumbar puncture
Seizure at onset of stroke
Anti-coagulants or heparin in the last 48 hours

Question 10

How is stroke managed in the initial 24 hours?

Answer 10

Exclude hypoglycaemia and take corrective measures to prevent it.
IV access
Swallow screening
IV fluids- 0.9% saline unless cardiac failure suspected
Monitor temperature- look for signs of infection if high and send off relevant bloods, urine, sputum culture etc.
Monitor oxygen sats- if less than 95% give oxygen and check ABGs. Check for chest infection. Consider chest physiotherapy.

Question 11

How is a stroke defined?

Answer 11

A rapid onset neurological deficit resulting from altered blood flow to the brain lasting >24 hours.
In clinical practice, the term stroke is used synonymously with ischaemic stroke, though technically haemorrhage causing deficit >24 hours is also a stroke.

Question 12

What is an ischaemic stroke?

Answer 12

• 85% of strokes.
  
  • Ischaemia due to cerebrovascular thrombosis or embolus. Emboli typically originate from the heart (AF/MI/IE/valve disease), aortic arch, carotid artery (atheroma or dissection), or vertebral artery (dissection).

Question 13

What is a haemorhagic stroke?

Answer 13

• ntracerebral (intraparenchymal or intraventricular), subarachnoid.
  
  • Causes: vascular abnormality (aneurysm, AVM), HTN, coagulopathy, vasculitis, or amyloidosis.

Question 14

What is a TIA?

Answer 14

• Symptoms last <24 hours.

* Stroke and TIA are collectively known as cerebrovascular events (CVE) or cerebrovascular accidents (CVA).

Question 15

What signs and symptoms might be seen in a patient with stroke/TIA?

Answer 15

• Focal neurological signs, usually ‘negative’ i.e. weak, numb (as opposed to ‘positive’ signs like pain). Onset is sudden, possibly waking from sleep, and symptoms worsen within hours.
  
  • Ischaemic stroke: there may also be signs of an embolic source e.g. murmur (valve disease), fever (infective endocarditis), carotid bruit (carotid artery disease). Loss of consciousness is rare.
  • Haemorrhagic stroke: meningism, headache, and often coma within hours.

Question 16

How is an anterior circulation stroke defined according to the oxford bamford classification?

Answer 16

• Results from occlusion of the internal carotid (ICA), middle cerebral (MCA), or anterior cerebral arteries (ACA).
Total anterior circulation stroke (TACS) is all 3 of the following, and partial anterior circulation stroke (PACS) is number 2 alone or any 2 of 3:
  
  • Motor or sensory deficits – contralateral to the lesion – in 2 out of 3 of the face, arm, and legs. Initially weak, flaccid, and areflexic, later UMN signs and less weakness. These signs alone = lacunar stroke. Predominant leg symptoms suggest ACA stroke, while predominant arm and face symptoms suggest MCA stroke.
  • Impaired higher function: aphasia (if in dominant hemisphere), apraxia, agnosia, hemispatial neglect (if in non-dominant hemisphere), altered level of consciousness. This alone = PACS.
  • Visual field changes, especially homonymous hemianopia. This alone = POCS.

Question 17

How is a posterior circulation stroke defined according to the oxford bamford classification?

Answer 17

• Results from occlusion in the vertebro-basilar system or posterior cerebral artery.
Any of the following presentation(s):
  
  • CN palsy plus contralateral motor or sensory deficits of body.
  • Bilateral motor or sensory defect
  • Eye movement problems.
  • Isolated homonymous hemianopia.
  • Cerebellar lesions.
  • Locked-in-syndrome, due to occlusion of the basilar artery affecting the pons.
  • Lateral medullary syndrome: posterior-inferior cerebellar artery occlusion leads to ipsilateral face signs – Horner’s, loss of temperature and pain sensation, dysarthria, dysphagia, palatal paresis – and contralateral body signs – loss of temperature and pain sensation.

Question 18

How is a lacunar stroke defined according to the oxford bamford criteria?

Answer 18

• Results from small infarct in end artery, usually in the anterior circulation. There is no loss of higher function, but the motor symptoms may be profound as it affects an area of the brain through which many motor white matter tracts pass.
Various presentations, including:
  
  • Unilateral motor and/or sensory deficits.
  • Ataxic hemiparesis: ipsilateral clumsiness and weakness, as opposed to cerebellar dysfunction (POCS) which is just clumsy.
  • Dysarthria and clumsy hand.

Question 19

What are the risk factors for stroke?

Answer 19

• Demographic and lifestyle:
  
  • Demographic: ↑age, male, non-white.
  • Lifestyle: smoking, alcohol, combined pill.
• Vascular risk factors:
  
  • Major CVD risk factors: HTN, diabetes, ↑cholesterol.
  • Existing CVD: heart disease (valvular, IHD, AF), PVD, previous stroke, carotid bruit.
• Abnormal clotting:
  
  • Thrombophilia (e.g. polycythaemia, APS) → ischaemic stroke.
  • Coagulopathy (e.g. warfarin, liver disease) → haemorrhagic stroke.
• Inflammatory and congenital:
  
  • Vasculitis: SLE, TA.
  • Homocystinuria
  • Amyloid angiopathy.
  • Mitochondrial disease.
  • Syphilis

Question 20

What differential diagnosis list would be appropriate in a suspected stroke patient?

Answer 20

• M8S:
  
  • Migraine
  • Sugar: hypoglycaemia.
  • Seizures, especially Todd’s palsy.
  • Sepsis, encephalitis.
  • Syncope
  • SDH
  • Space occupying lesion.
  • Old Strokes with intercurrent illness.
  • Somatisation

Question 21

Which investigations are appropriate/useful in suspected stroke patients?

Answer 21

• Imaging aids diagnosis, while most other tests look for risk factors and complications.
Bloods:
  
  • FBC: polycythaemia, ↓platelets (potential cause of stroke and contraindication to some treatments).
  • ESR: vasculitis.
  • U&Es and LFTs: look for renal, electrolyte, or hepatic causes of neurological symptoms.
  • Coag: looking for stroke cause and prior to initiating thrombolysis or antiplatelets.
  • Glucose
  • Cholesterol
• CV tests:
  
  • ECG: AF.
  • CXR: may show LVF from HTN, large atria as source of embolus, or aspiration pneumonia.
  • Echo: if embolic source suspected.
  • Carotid duplex US for potential endarterectomy candidates i.e. TIA or non-disabling stroke.
• Neuroimaging:
  
  • CT: rules out haemorrhage and tumour, but initially may be normal in ischaemia. Allows thrombolysis to proceed if -ve.
  • CT angiography (CTA): detects large vessel occlusion to identify potential thrombectomy candidates.
  • MRI: shows infarct more clearly and is as sensitive as CT for bleed. However, less widely available.
  • In TIA, CT only indicated acutely if suspecting alternative diagnosis that CT can detect (e.g. bleed). If imaging considered necessary in TIA clinic (e.g. to define ischemic territory or rule out alternative diagnoses), MRI is preferred.

Question 22

How is management of an acute stroke approached?

Answer 22

• Overall approach


Acute stroke management:

* Monitor to prevent ↓O2, ↓glucose, ↓BP, infection.
* Imaging within 1 hour.
* DVT prophylaxis if immobile. Intermittent pneumatic compression 1st line, plus LMWH only if very high risk.
* Admit to specialist stroke ward.
* MDT: speech and language therapy (SALT), physio, and OT.

Question 23

What is important in the management of an acute TIA?

Answer 23

• Refer all patients with suspected TIA for specialist assessement within 24h.

Question 24

How is reperfusion therapy for ischaemic stroke carried out?

Answer 24

• Reperfusion therapy for ischaemic stroke:
  
  • Thrombolysis: alteplase or tenecteplase IV for patients presenting within 4.5 hours of symptom onset.
  • Thrombectomy: consider for patients with large vessel occlusion (on CT/MR angiography) and non-infarcted tissue beyond the occlusion (an ‘ischaemic penumbra’, as seen on CT perfusion or diffusion-weighted MRI). Effective up to 24 hours post symptom onset, though only 10% eligible.

Question 25

How is anti-platelet therapy for ischaemic stroke and TIA carried out?

Answer 25

• tart aspirin 300 mg OD 24 hours after alteplase, or immediately if outside the treatment window or in TIA. Continue for 2 weeks then switch to long-term antiplatelet.
  
  • Consider dual-antiplatelet therapy (aspirin plus clopidogrel) for 3 weeks in high risk TIA (ABCD2 ≥4) or minor ischaemic stroke (NIHSS ≤3).

Question 26

How is a haemorrhagic stroke managed?

Answer 26

• Neurosurgical referral. Few interventions for intracerebral bleeds, but SAH may be coiled or clipped.

Question 27

Which steps are important in the prevention of a second stroke/TIA?

Answer 27

• ntiplatelet: clopidogrel 1st line, aspirin plus modified-release dipyridamole 2nd line.
  
  • Anticoagulation (DOAC or warfarin) instead of antiplatelets if there is AF.
  • Statins for all.
  • Screen for and treat hypertension as per the normal pathway.
  • Carotid endarterectomy or stenting if there is ≥50% carotid artery stenosis. 5% perioperative stroke risk. More likely to be done post-TIA or non-disabling stroke, as after a disabling stroke it’s essentially too late.
  • Lifestyle: improve diet, ↑exercise, ↓smoking, ↓alcohol. No driving for 1 month.

Question 28

How does thrombolysis in ischaemic stroke work and what are the risks and benefits?

Answer 28

• Alteplase is the only licensed thrombolytic agent for ischaemic stroke in the UK. Tenecteplase is an alternative with similar mechanism, risks, and benefits.
Mechanism
A recombinant tissue plasminogen activator (tPA), catalysing plasminogen conversion to plasmin, which degrades fibrin.
Risks and benefits in stroke
  
  • Increased risk of intracranial bleed and 7 day mortality (2% absolute increase). Repeat CT 24 hours after administration to look for haemorrhage.
  • Mortality difference (vs. placebo) evens out by 3-6 months, at which point it shows a 10% absolute increase in the number of people achieving a good functional outcome. This benefit is only achieved if given within 3 hours, and possibly up to 4.5 hours. However, there are questions about the methodological reliability and consistency of this beneficial finding in the literature.

Question 29

What are the cautions and contra-indications to thrombolysis?

Answer 29

• Bleeding:
  
  • Ongoing bleeding (except menstruation).
  • History of CNS bleeding.
• Unstable:
  
  • Seizures at presentation.
  • Uncontrolled HTN >180/110.
• Recent medical history:
  
  • LP in the past week.
  • Ischaemic stroke or head injury within the last 3 months.
  • Surgery or major trauma within the last 2 weeks.
• Cautions:
  
  • Anticoagulated
  • Coagulopathy

Question 30

What possible complications can occur in stroke patients?

Answer 30

• Complications:
  
  • Short-term: DVT, aspiration pneumonia, seizures, cerebral oedema and ↑ICP.
  • Long-term: persistent neurological deficits, epilepsy.

Question 31

What is the prognosis for stroke patients?

Answer 31

• Most recovery happens in first 3 months.
  
  • Overall 20% mortality within 1 month.
  • TACS at 12 months: 50% mortality, 45% disabled, and 5% fine.
  • Non-TACS at 12 months: 15% mortality, 35% disabled, 50% fine.