Ischaemic Stroke

Related Subjects: |Acute Stroke Assessment (ROSIER/NIHSS) |Atrial Fibrillation |Atrial Myxoma |Causes of Stroke |Ischaemic Stroke |Cancer and Stroke |Cardioembolic stroke |CT Basics for Stroke |Endocarditis and Stroke |Haemorrhagic Stroke |Stroke Thrombolysis |Hyperacute Stroke Care |Hypertension |Thrombophilia testing |Cerebral Venous Sinus thrombosis |Small Vessel Disease |CADASIL |CARASIL

📖 About

• Sudden onset focal neurological deficit due to reduced cerebral blood flow → infarction.
• ~80% of all strokes are ischaemic (rest haemorrhagic).
• Stroke includes brain, spinal cord, and retinal ischaemia (WHO definition).
• Diagnosis increasingly based on imaging (CT/MRI DWI) rather than just time.

🔎 Trial of Org 10172 in Acute Stroke Treatment (TOAST)

• Large-artery atherosclerosis
• Cardioembolism
• Small-vessel occlusion (lacunar)
• Other determined aetiology
• Undetermined aetiology (cryptogenic)

🧠 Causes

• Large Arterial Thrombosis: Atherosclerosis of ICA/MCA/PCA, plaque rupture, distal embolisation.
• Embolism: AF, endocarditis, LV thrombus post-MI, mitral stenosis, atrial myxoma, paradoxical embolus (PFO), aortic arch plaque, dissection.
• Small vessel disease: Lipohyalinosis → lacunar strokes (<15 mm) in internal capsule, basal ganglia, thalamus, pons.
• Venous thrombosis: Sinus thrombosis with secondary venous infarction ± haemorrhage.
• Low flow: Hypotension/shock → watershed infarcts.
• Cryptogenic: No clear cause despite work-up.

⚠️ General Risk Factors

• Hypertension, diabetes, hyperlipidaemia, smoking, age
• Arterial dissection (trauma, fibromuscular dysplasia, Marfan/Ehlers-Danlos)
• Vasculitis (GCA, PAN, Behçet’s, lupus)
• Prothrombotic states (Factor V Leiden, Protein C/S deficiency, antiphospholipid, malignancy)
• Migraine with aura, OCP/oestrogens

🩻 Investigations

• Bloods: FBC, U&E, LFT, glucose, lipids, ESR/CRP.
• ECG (AF, MI, LVH, cardiomyopathy).
• CXR (exclude cardiopulmonary causes, but don’t delay CT).
• CT Head (urgent): exclude haemorrhage. Early signs: dense MCA sign, loss of insular ribbon, grey-white loss.
• MRI DWI: more sensitive, esp. for small/early infarcts.
• Further tests (senior decision): carotid Doppler, echocardiogram, Holter (AF), vasculitis/thrombophilia screen in young.

🧾 Clinical Syndromes

• MCA: Contralateral hemiplegia (face/arm > leg), hemisensory loss, homonymous hemianopia, aphasia (dominant), neglect (non-dominant).
• ACA: Leg > arm weakness, urinary incontinence, apathy/abulia, primitive reflexes.
• Vertebrobasilar: CN palsies, contralateral weakness, sensory loss, ataxia, Horner’s syndrome.
• Lacunar: Pure motor, pure sensory, dysarthria-clumsy hand, ataxic hemiparesis.

💊 Management

• Thrombolysis: Alteplase if onset <4.5 hrs, NIHSS 4–25, CT excludes haemorrhage.
• Mechanical thrombectomy: Consider if large vessel occlusion (MCA/ICA, ≤6 hrs; up to 24 hrs in selected).
• Antiplatelet: Aspirin 300 mg OD x2 weeks then clopidogrel 75 mg OD long term. (Dual therapy not routine except in minor stroke/TIA, short course).
• Anticoagulation (AF): Start between 3–14 days depending on infarct size (TIA day 1, small stroke day 3, moderate day 6, large stroke ≥2 wks).
• BP control: Avoid acute lowering unless BP >220/120 or candidate for thrombolysis (<185/110).
• Lipids: Atorvastatin 80 mg after 48 hrs (unless contraindicated).
• Glucose: Keep 4–11 mmol/L. Avoid hypoglycaemia.
• Fluids/Nutrition: Swallow screen. NG feeding if unsafe swallow. IV fluids if nil orally.
• Oxygen: Only if sats <95%.
• VTE prophylaxis: Intermittent compression stockings. LMWH only if high-risk immobile.
• Surgery: Hemicraniectomy for malignant MCA infarct in <60 yrs.
• Carotid endarterectomy: If symptomatic carotid stenosis >70% and mild/moderate stroke.
• Rehab: Early supported discharge, MDT therapy essential.

📚 Key Classification: TOAST

• Large-artery atherosclerosis
• Cardioembolism
• Small vessel occlusion
• Other determined
• Undetermined (cryptogenic)