Anterior Circulation
3 syndromes
MCA + ACA (ICA occlusion)
17% of ischaemic strokes
Clinical Features
All 3 required: (1) contralateral hemiparesis ± hemisensory loss, (2) homonymous hemianopia, (3) higher cortical dysfunction (dysphasia if dominant / neglect if non-dominant)
Red Flags & Complications
⚠ Malignant MCA oedema (peak 48–72h) — consider decompressive hemicraniectomy if age <60
⚠ Haemorrhagic transformation — highest risk with large infarct volume + reperfusion
⚠ High aspiration risk — formal swallow assessment mandatory before oral intake
Prognosis
Worst prognosis of OCSP subtypes
~60% 1-year mortality. Only 4% functionally independent at 1 year (Bamford 1991). NIHSS typically >15. If thrombolysed/thrombectomised early, outcomes improve substantially (HERMES: NNT 2.6 for ≥1 mRS level improvement).
Expected mRS: 4–6
MCA branch
34% of ischaemic strokes
Clinical Features
2 of 3 TACI criteria, OR isolated higher cortical dysfunction, OR restricted motor/sensory deficit (e.g. monoparesis)
Superior division: face + arm > leg weakness, Broca's aphasia (dominant), contralateral gaze preference
Inferior division: Wernicke's aphasia (dominant), contralateral hemianopia/quadrantanopia, neglect (non-dominant)
Red Flags
⚠ Highest early recurrence rate (~17% at 1 year)
⚠ Inferior division strokes may present without weakness — often misdiagnosed
Prognosis
Moderate prognosis; high recurrence risk
~16% 1-year mortality. Functional independence at 1 year ~55%.
Expected mRS: 1–4
ACA (A2 segment)
Clinical Features
Contralateral leg > arm weakness (motor strip topography)
Abulia / akinetic mutism (bilateral ACA or dominant mesial frontal)
Urinary incontinence (superior frontal involvement)
Prognosis
Generally better than MCA syndromes
Leg weakness can be prolonged but functional arm use is preserved.
Expected mRS: 1–3
Posterior Circulation
5 syndromes
Vertebrobasilar system
24% of ischaemic strokes
Clinical Features
Ipsilateral CN palsy + contralateral motor/sensory deficit, OR bilateral deficits, OR conjugate gaze disorder, OR cerebellar dysfunction, OR isolated hemianopia
Red Flags
⚠ 39% are FAST-negative — high miss rate in ED
⚠ NIHSS systematically underscores posterior circulation deficits
⚠ Basilar occlusion can present with fluctuating symptoms → catastrophic deterioration
Prognosis
Best early functional outcome; highest late recurrence
~19% 1-year mortality. Best functional independence (~62%). However, 20% late recurrence at 5 years.
Expected mRS: 0–3
PICA / vertebral artery
Clinical Features
Ipsilateral: facial numbness (V), Horner's, cerebellar ataxia, hoarseness/dysphagia (IX/X)
Contralateral: spinothalamic sensory loss (pain/temp)
Lateropulsion (falling toward lesion), vertigo, nystagmus
Key absence: NO limb weakness (corticospinal tract spared)
Red Flags
⚠ Severe dysphagia — aspiration risk; NGT often required
⚠ May present as acute vertigo → misdiagnosed as vestibular neuritis. Use HINTS exam
Prognosis
Generally good motor prognosis
Most recover well functionally (mRS 0–2). Dysphagia resolves in ~2/3. Central pain (Déjerine-Roussy) can develop and be debilitating.
Expected mRS: 0–2
Basilar artery (ventral pons)
Clinical Features
Quadriplegia (bilateral corticospinal tracts)
Bilateral facial + bulbar paralysis
Anarthria, aphagia
PRESERVED: consciousness, vertical eye movements, blinking
Red Flags
⚠ MUST be distinguished from coma — patient is fully aware
⚠ EEG shows normal waking patterns (confirms awareness)
⚠ Risk of being inappropriately treated as GCS 3 → premature withdrawal of care
Prognosis
Devastating but not uniformly fatal
Historical 1-year mortality ~60–70%. ~10% achieve partial motor recovery. Long-term survivors report higher quality of life than expected.
Expected mRS: 5 (typically)
Lacunar Syndromes
5 syndromes
Internal capsule / pons
25% of all strokes
Clinical Features
Contralateral face, arm, and leg weakness (proportional)
No sensory loss, visual field deficit, or cortical dysfunction
Prognosis
Best prognosis of lacunar syndromes
~75% achieve functional independence. Motor recovery often substantial over 3–6 months.
Expected mRS: 0–2
VPL thalamic nucleus
Clinical Features
Contralateral numbness / paraesthesiae (face, arm, leg)
All modalities affected (touch, pinprick, proprioception, vibration)
No motor deficit, no cortical signs
Red Flags
⚠ Thalamic pain syndrome (Déjerine-Roussy) can develop weeks–months later
Prognosis
Good functional prognosis; neuropathic pain risk
Most patients return to independence. 8–16% develop chronic thalamic pain syndrome.
Expected mRS: 0–1
Haemorrhagic Stroke
6 types
Lenticulostriate arteries
Clinical Features
Contralateral hemiparesis + hemisensory loss
Homonymous hemianopia
Global aphasia (dominant) / neglect (non-dominant)
Ipsilateral gaze deviation ('eyes look toward lesion')
Red Flags
⚠ Haematoma expansion in first 24h (~38%) — repeat CT at 6h
⚠ IVH extension → acute hydrocephalus
⚠ Midline shift > 5mm → consider surgical evacuation
Prognosis
Variable; volume-dependent (ICH Score)
Small ICH (<30mL) with preserved consciousness has reasonable recovery. INTERACT2: intensive BP lowering (SBP <140) improves outcomes.
Expected mRS: 2–6
Superior cerebellar artery
Clinical Features
Acute severe headache, nausea/vomiting
Ipsilateral limb ataxia / gait ataxia / inability to walk
Dysarthria
NO limb weakness initially (unless brainstem compression)
Red Flags
⚠ NEUROSURGICAL EMERGENCY — rapid deterioration from brainstem compression
⚠ Surgical evacuation if ≥3cm diameter OR GCS declining OR hydrocephalus
⚠ Decerebrate posturing = brainstem compression → immediate surgery
Prognosis
Bimodal: excellent if early surgery; devastating without
Most 'surgically treatable' ICH. With early decompression, can achieve excellent recovery (mRS 0–2). Without surgery, brainstem compression is often fatal.
Expected mRS: 0–2 (post-surgery) / 5–6 (untreated)
Aneurysmal rupture (~85%)
Clinical Features
Thunderclap headache ('worst headache of my life') — sudden onset, maximal at onset
Meningism (neck stiffness, photophobia)
Loss of consciousness (transient or sustained)
Grading: Hunt-Hess I (mild headache) → V (coma)
Red Flags
⚠ Rebleeding: highest risk first 24h. Aneurysm must be secured within 24h (Class I)
⚠ Delayed cerebral ischaemia (DCI): peak day 4–14. Nimodipine 60mg q4h × 21 days
⚠ Acute hydrocephalus → urgent EVD
⚠ Avoid prophylactic phenytoin (worse cognitive outcomes). Use levetiracetam if needed
Prognosis
30-day mortality ~35%
Hunt-Hess I–II: ~85% good outcome. Grade III: ~50%. Grade IV–V: <20%. Survivors: ~50% have permanent cognitive deficits.
Expected mRS: 0–2 (low grade) / 4–6 (high grade)
Complications & Red Flags
Across all stroke subtypes
Haemorrhagic Transformation
Timing: 24h–14d (peak 48–72h)
Risk: Large infarct, reperfusion, anticoagulation, AF
ECASS: HI1/HI2 (petechial, asymptomatic) vs PH1/PH2 (parenchymal haematoma — PH2 causes clinical deterioration). Repeat CT if any decline post-thrombolysis.
Cerebral Oedema & Herniation
Timing: 24–96h (peak 48–72h)
Risk: TACI, large MCA, younger patients
Malignant MCA oedema: ~80% fatal without intervention. Decompressive hemicraniectomy if age <60, declining GCS, >50% MCA territory. NNT 2 for survival.
Aspiration Pneumonia
Timing: First 7 days (highest risk days 1–3)
Risk: Dysphagia (~37–78%), reduced consciousness, brainstem stroke
Nil by mouth until formal swallow assessment. Pneumonia is leading cause of non-neurological death post-stroke.
VTE (DVT / PE)
Timing: Days 2–14+
Risk: Immobility, hemiparesis. DVT up to 50% without prophylaxis
Pneumatic compression (Class I). LMWH from day 1–2 for ischaemic. For ICH: pneumatic immediately; pharmacological after 48h if stable.
Seizures
Timing: Early <7d; Late >7d
Risk: Cortical involvement (lobar ICH >> deep ICH)
Early seizures: 2–6% ischaemic, ~28% lobar ICH. Do not prophylax routinely. In SAH: avoid phenytoin (worse cognition).
Post-Stroke Depression
Timing: Weeks to months (peak 3–6 months)
Risk: Pre-existing depression, severe disability, social isolation
Affects ~19–33%. Impairs rehab engagement. Screen with PHQ-9. SSRIs first-line.
Prognostic Scores
Quick reference
ICH Score
Hemphill et al. Stroke 2001
GCS 3–4
2
GCS 5–12
1
GCS 13–15
0
ICH volume ≥30 cm³
1
IVH present
1
Infratentorial origin
1
Age ≥80 years
1
30-Day Mortality
0
0%
1
13%
2
26%
3
72%
4
97%
5
100%
NIHSS → Prognosis
Saver & Altman, Stroke 2012
0–5
Minor
~70–80% independent (mRS 0–2)
6–10
Moderate
~45–55% independent
11–15
Moderate–Severe
~20–35% independent
16–20
Severe
~10–20% independent
>20
Very Severe
<5% independent; high mortality
Hunt-Hess Grade (SAH)
AHA/ASA 2023 SAH Guideline
I
Asymptomatic or mild headache
~70% good outcome
II
Moderate–severe headache, nuchal rigidity
~60% good outcome
III
Drowsy, mild focal deficit
~50% good outcome
IV
Stupor, moderate–severe hemiparesis
~20% good outcome
V
Coma, decerebrate posturing
<10% good outcome