🧠 The Oxford Community Stroke Project (OCSP) classification is widely used in UK practice to predict stroke prognosis from clinical features alone, before imaging. It divides strokes into four main categories.

📖 Terminology

TACS: Total Anterior Circulation Stroke
PACS: Partial Anterior Circulation Stroke
LACS: Lacunar Stroke
POCS: Posterior Circulation Stroke

Category	Stands for	Key Clinical Features	Typical Vascular Territory
TACS	Total Anterior Circulation Stroke	All three of: • Higher cortical dysfunction (e.g. dysphasia, neglect) • Homonymous visual field defect • Contralateral motor and/or sensory deficit of ≥2 regions (face/arm/leg)	Large MCA territory often including ACA/MCA border-zone; proximal ICA/MCA occlusion.
PACS	Partial Anterior Circulation Stroke	Any one of: • Higher cortical dysfunction alone • Two of the three TACS components • Pure motor/sensory deficit more restricted than TACS	Branch occlusions in MCA or ACA territory; smaller cortical or subcortical infarcts in anterior circulation.
LACS	Lacunar Stroke	Pure lacunar syndromes with no cortical signs: • Pure motor • Pure sensory • Sensorimotor • Ataxic hemiparesis / dysarthria–clumsy hand	Small deep perforating artery infarcts in internal capsule, thalamus, basal ganglia, pons, etc.
POCS	Posterior Circulation Stroke	One or more of: • Brainstem signs (e.g. diplopia, dysarthria, dysphagia, vertigo) • Cerebellar signs (e.g. ataxia) • Isolated homonymous visual loss	Vertebrobasilar system – brainstem, cerebellum, occipital lobes, thalami.

🧾 Classification Suffixes

(S): Syndrome – based on clinical diagnosis before imaging (e.g. TACS)
(I): Infarct – confirmed by imaging (e.g. TACI)
(H): Haemorrhage – confirmed bleed (e.g. TACH)

🌐 Total Anterior Circulation Stroke (TACS)

⚠️ All three of the following must be present:

Higher cortical dysfunction: Dysphasia (usually left hemisphere) or visuospatial neglect (usually right)
Homonymous hemianopia: Visual field loss on the same side in both eyes
Motor/sensory deficit: Face + arm + leg involvement (at least two regions)
Prognosis: 💀 ~40% 30-day mortality; survivors often have severe disability

🌍 Partial Anterior Circulation Stroke (PACS)

✅ Any two of the three TACS features or isolated higher cortical dysfunction:

Dysphasia or visuospatial neglect
Partial homonymous hemianopia
Weakness/sensory loss in face, arm, or leg (not all three)
Prognosis: ⚖️ ~10% 30-day mortality; usually small cortical infarcts

🔬 Lacunar Stroke (LACS)

Pathology: Occlusion of small perforators (internal capsule, thalamus, basal ganglia, pons)
Features: ❌ No cortical signs (no aphasia, neglect, or apraxia)
Syndromes:
- Pure motor hemiparesis
- Pure sensory stroke
- Sensorimotor stroke
- Ataxic hemiparesis
- Dysarthria–clumsy hand
Prognosis: 🙂 <3% 30-day mortality; often good recovery

🌀 Posterior Circulation Stroke (POCS)

Symptoms: Dizziness, vertigo, diplopia, nausea/vomiting, nystagmus, cerebellar signs, Horner’s syndrome
Structures: Brainstem, occipital lobes, thalami (vertebral + basilar supply)
Key Syndromes: “Top of the basilar” – bilateral infarcts with coma, visual and cranial nerve involvement
Signs: Cerebellar ataxia, dysphagia, visual field defects, movement disorders (hemiballismus, chorea)
Prognosis: Variable – many do well, but brainstem involvement can be devastating

🩺 Management Considerations

TACS: Urgent stabilization, thrombolysis/thrombectomy if eligible; monitor for oedema + herniation
PACS: Thrombolysis if eligible; secondary prevention + rehab for language/neglect deficits
LACS: Antiplatelets + vascular risk factor control (esp. hypertension); usually good rehab potential
POCS: Careful imaging and neuro assessment; thrombolysis/thrombectomy possible; manage brainstem/cerebellar complications (e.g. hydrocephalus)

📊 Prognosis Summary

🔴 TACS: Poor prognosis (40% mortality at 30 days)
🟠 PACS: Moderate (10% mortality)
🟢 LACS: Favourable (<3% mortality, good recovery)
🔵 POCS: Variable – depends on extent (mild cerebellar vs severe brainstem stroke)

📚 References

💡 Exam Pearl: If you see all three features (cortical dysfunction + hemianopia + motor/sensory deficit), always call it a TACS until proven otherwise. Prognosis is much worse than PACS or LACS.

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Oxford community stroke project (Bamford)