Why Stroke Assessment Is Examined
Stroke is the second most common cause of death in the UK and a leading cause of adult disability. TIA is a medical emergency — 10% of TIA patients have a stroke within 48 hours, and prompt assessment reduces this risk by 80%. OSCEs test stroke recognition, acute management decisions, TIA risk stratification, and secondary prevention counselling.
⚠️ Red Flag
Time is brain. In ischaemic stroke, approximately 1.9 million neurons are lost every minute of untreated large vessel occlusion. Every OSCE stroke scenario should begin: "I would activate the stroke pathway immediately and get the patient to a stroke unit."
FAST Recognition
| Letter | Domain | What to assess |
|---|---|---|
| F | Face | Unilateral facial droop — ask patient to smile |
| A | Arm | Arm weakness — both arms raised, watch for drift |
| S | Speech | Slurred, word-finding difficulty, or not understanding |
| T | Time | Time of symptom onset (or last seen well) |
FAST-negative strokes — up to 30% of strokes have posterior circulation or non-FAST symptoms: diplopia, vertigo, ataxia, dysphagia, hemianopia, or sudden severe headache (SAH). Use ROSIER (Recognition Of Stroke In the Emergency Room) in hospital for a more complete assessment.
ROSIER Score
| Feature | Score |
|---|---|
| Asymmetric facial weakness | +1 |
| Asymmetric arm weakness | +1 |
| Asymmetric leg weakness | +1 |
| Speech disturbance | +1 |
| Visual field defect | +1 |
| Seizure | -1 |
| Loss of consciousness or syncope | -1 |
Score above 0 = stroke likely. First exclude hypoglycaemia — check blood glucose before scoring.
Types of Stroke
| Type | Proportion | Mechanism |
|---|---|---|
| Ischaemic | 85% | Embolic or thrombotic occlusion of a cerebral artery |
| Haemorrhagic (intracerebral) | 10% | Rupture of a vessel within brain parenchyma |
| Subarachnoid haemorrhage | 5% | Rupture of cerebral aneurysm — thunderclap headache |
Immediate imaging: Non-contrast CT head (distinguishes haemorrhagic from ischaemic — essential before thrombolysis).
Immediate Management — Ischaemic Stroke
Thrombolysis (Alteplase)
| Parameter | Detail |
|---|---|
| Drug | Alteplase (recombinant tPA) 0.9 mg/kg IV (max 90 mg) — 10% as bolus, remainder over 60 minutes |
| Time window | Within 4.5 hours of symptom onset (or last known well) |
| CT requirement | Must exclude haemorrhage first |
Absolute contraindications to thrombolysis:
- Haemorrhage on CT
- Symptom onset over 4.5 hours ago (or unknown onset)
- Seizure at onset (if not certain it is Todd's paresis)
- Active bleeding or recent major surgery (within 14 days)
- Anticoagulation with therapeutic INR or DOAC taken within 48 hours
- Blood pressure above 185/110 mmHg (treat first)
- Platelet count below 100 x 10⁹/L
Mechanical Thrombectomy
- For large vessel occlusion (proximal MCA, ICA, basilar artery)
- Within 6 hours (up to 24 hours with perfusion imaging in selected patients)
- Performed by interventional neuroradiology
- Significantly reduces disability in eligible patients
Supportive Management
- Aspirin 300 mg (if haemorrhage excluded) — start immediately, switch to clopidogrel 75 mg OD at 2 weeks
- Maintain oxygen saturation above 95%
- Target blood pressure below 185/110 if thrombolysing; avoid aggressive lowering otherwise (cerebral autoregulation impaired)
- NBM until swallow screen performed by trained staff
- Admit to hyperacute stroke unit (HASU)
NIH Stroke Scale (NIHSS) — Overview
The NIHSS quantifies stroke severity and guides treatment decisions. It assesses 11 domains (total 0-42):
| Domain | Max score | What it assesses |
|---|---|---|
| Level of consciousness | 3 | Responsiveness and orientation |
| Gaze | 2 | Horizontal eye movement |
| Visual fields | 3 | Hemianopia |
| Facial palsy | 3 | Asymmetric weakness |
| Motor arm (each) | 4 | Drift in outstretched arm |
| Motor leg (each) | 4 | Leg drift at 30 degrees |
| Limb ataxia | 2 | Co-ordination |
| Sensory | 2 | Unilateral sensory loss |
| Language | 3 | Aphasia severity |
| Dysarthria | 2 | Speech clarity |
| Extinction/neglect | 2 | Inattention |
🧠 Mnemonic
NIHSS severity thresholds:
- 0 = no stroke
- 1-4 = minor
- 5-15 = moderate
- 16-20 = moderate-severe
- 21+ = severe
Thrombolysis is generally considered for NIHSS 4-25.
TIA Assessment — ABCD2 Score
TIA = transient neurological deficit resolving completely within 24 hours (usually under 1 hour), no infarction on MRI DWI.
🧠 Mnemonic
ABCD2 score:
- A ge 60 or above = 1
- B lood pressure 140/90 or above at presentation = 1
- C linical features: unilateral weakness = 2; speech disturbance without weakness = 1; other = 0
- D uration: 60 minutes or more = 2; 10-59 minutes = 1; under 10 minutes = 0
- D iabetes = 1
Maximum 7 points.
| Score | 2-day stroke risk | Management |
|---|---|---|
| 0-3 | Low (1%) | Specialist assessment within 24 hours (NICE) |
| 4-5 | Moderate (4%) | Specialist assessment within 24 hours |
| 6-7 | High (8%) | Admit and investigate immediately |
NICE 2019 guidance: All TIA patients should be seen by a specialist within 24 hours of symptom onset, regardless of ABCD2 score.
Secondary Prevention After Stroke/TIA
| Intervention | Detail |
|---|---|
| Antiplatelet | Clopidogrel 75 mg OD (first-line); aspirin + dipyridamole if clopidogrel not tolerated |
| Anticoagulation | Warfarin or DOAC if AF is the cause (not antiplatelets) |
| Blood pressure control | Target below 130/80 mmHg — start 2 weeks after stroke |
| Statin | Atorvastatin 80 mg OD (high-intensity) — start immediately for ischaemic stroke |
| AF management | Rate or rhythm control; anticoagulation with DOAC |
| Lifestyle | Smoking cessation, alcohol reduction, exercise, Mediterranean diet |
| Carotid imaging | Doppler or CT angiography for carotid stenosis — endarterectomy if 50-99% symptomatic stenosis |
Frequently Asked Questions
"What is the difference between a TIA and a stroke?"
A stroke is a focal neurological deficit caused by infarction or haemorrhage that persists for more than 24 hours (old definition) or is confirmed on imaging. A TIA is a transient episode of neurological dysfunction with no evidence of infarction on imaging — classically resolving within 1 hour. The distinction matters because TIA patients are at high short-term stroke risk and require urgent assessment and secondary prevention.
"Why is blood pressure not aggressively lowered in acute ischaemic stroke?"
In the acute phase of ischaemic stroke, the infarcted and penumbral tissue around the core loses cerebral autoregulation. Blood flow in this region becomes pressure-dependent. Aggressive BP lowering reduces perfusion to the ischaemic penumbra, potentially increasing infarct size. Permissive hypertension (up to 180/110 without thrombolysis) is therefore standard. Only lower BP before thrombolysis if above 185/110.
"What is posterior circulation stroke and why is it missed?"
Posterior circulation strokes affect the brainstem, cerebellum, and occipital lobes — supplied by the vertebral and basilar arteries. They do not cause the classic FAST symptoms (facial droop, arm weakness, speech) and are therefore frequently missed. Features include: diplopia, dysphagia, dysarthria, dizziness, ataxia, sudden severe headache, bilateral limb weakness, locked-in syndrome. The 4D score helps risk-stratify posterior circulation TIA presentations.
"When is anticoagulation rather than antiplatelet therapy used after stroke?"
When atrial fibrillation (or another cardioembolic source) is the cause of the stroke. Anticoagulation (warfarin or DOAC) is significantly more effective than aspirin at preventing cardioembolic stroke recurrence. Start timing: NICE recommends starting after 2 weeks for ischaemic stroke (to avoid haemorrhagic transformation) or after 14 days if large infarct — unless AF is paroxysmal and infarct is small, in which case 1 week is reasonable.
"What imaging is required for stroke and TIA?"
Stroke: non-contrast CT head immediately to exclude haemorrhage. MRI brain with DWI sequence (diffusion-weighted imaging) is more sensitive for acute ischaemia — performed within 24 hours where available. TIA: MRI DWI to exclude completed infarction; CT/MRI angiography if posterior circulation or large vessel involvement suspected; carotid Doppler for anterior circulation TIA. Echocardiography and cardiac monitoring (24-hour Holter) to detect AF and cardioembolic source.
Related Posts
- Neurological Examination OSCE — examining for focal neurological deficits in the stroke patient
- Atrial Fibrillation History OSCE — AF as the most common cardioembolic cause of stroke
- Glasgow Coma Scale OSCE — quantifying conscious level in the acute stroke patient