Stroke: Pathophysiology & Treatment Algorithm

1. Pathophysiology of Ischemic Stroke — Cascade Flowchart

Key Steps Explained

2. Acute Stroke Treatment Algorithm — Flowchart

3. Structured Treatment Algorithm (Text Supplement)

Step 1 — Recognition & Prehospital

• Identify stroke signs (FAST: Face, Arm, Speech, Time)
• Prehospital call ahead → Code Stroke activation on arrival

Step 2 — Immediate ED Assessment (ABCs + glucose)

• Airway, breathing, circulation
• Finger-stick glucose (treat hypo- and hyperglycaemia; target 60–180 mg/dL)
• Establish time last seen normal (LSN)
• NIHSS scoring

Step 3 — Emergency Neuroimaging

Step 4 — Reperfusion Decisions

IV Thrombolysis

• Agent: Alteplase 0.9 mg/kg IV (max 90 mg) OR Tenecteplase (single bolus)
• Window: ≤4.5 h from LSN (AHA/ASA 2019 guidelines)
• Key contraindication: BP >185/110 mmHg (must be controlled first), prior intracranial hemorrhage, active bleeding
• Give bolus in CT scanner → start infusion immediately

Endovascular Thrombectomy (EVT)

• Indicated if CTA shows ICA, M1, M2, or basilar artery occlusion
• Window: up to 24 h from LSN if favorable perfusion imaging (DAWN/DEFUSE-3 criteria)
• Can be combined with IV tPA ("bridging therapy")

Step 5 — Medical Support (all stroke patients)

Step 6 — Secondary Prevention (post-acute)

Step 7 — Rehabilitation

• Early mobilisation, speech therapy, physiotherapy
• Stroke unit care reduces mortality and disability independent of thrombolysis

Quick Summary Mnemonic

"Time = Brain" — 1.9 million neurons die every minute without reperfusion

Pathway: Suspect → CT (exclude bleed) → Time window → tPA if eligible → CTA → Thrombectomy if large vessel occlusion → Medical support → Secondary prevention → Rehab

Non-Pharmacological Treatment of Stroke

Phase 1 — Acute Non-Pharmacological Interventions

1. Reperfusion Procedures (Mechanical)

2. Decompressive Hemicraniectomy

• Indicated for malignant MCA infarct with severe cytotoxic oedema
• Most beneficial when performed <48 hours in patients <60 years of age
• Reduces 6-month mortality significantly (RescueICP data)
• Surgical options also include: ventriculostomy (CSF drainage) for raised ICP, evacuation of intracranial haematoma (for haemorrhagic stroke)

3. Temperature Management

• Fever is detrimental — every 1°C rise increases cerebral metabolic demand by 8–13%, escalates glutamate release and free radical production
• Treat all temperatures >38°C aggressively with surface cooling devices
• Targeted hypothermia (32–36°C) is an option in refractory raised ICP, though evidence for routine use in ischaemic stroke is limited

4. Airway & Positioning

• Maintain airway patency; intubate if GCS ≤8 or aspiration risk
• Head-of-bed positioning: generally 0–30° flat to optimise cerebral perfusion pressure in acute phase (unless oedema or aspiration risk mandates elevation)

5. DVT Prophylaxis (Mechanical)

• Pneumatic compression stockings — proven benefit in reducing DVT risk; safe alternative when heparin is contraindicated
• Early mobilisation when medically stable

Phase 2 — Rehabilitation (Post-Acute)

Stroke Unit Care

• Dedicated stroke units with multidisciplinary teams reduce mortality and disability independent of any drug therapy — one of the most evidence-based interventions in stroke care
• Telestroke/telemedicine services extend specialist care to peripheral hospitals
• Standardised stroke order sets and clinical pathways improve outcomes

Core Rehabilitation Therapies

Constraint-Induced Movement Therapy (CIMT)

• Immobilises the unaffected limb to force use of the paretic limb
• Shown to improve hemiparesis even years after stroke, demonstrating neural plasticity
• Evidence supports recruitment of previously unused neural pathways

Emerging Neuromodulation Therapies (Under Investigation)

Swallowing & Nutrition

• All stroke patients require formal swallow assessment before oral intake
• Nasogastric feeding or PEG tube for persistent dysphagia
• Nutritional support prevents aspiration pneumonia (a leading cause of post-stroke mortality)

Psychological & Social Support

• Post-stroke depression affects ~30% of patients — psychological counselling, peer support groups
• Family and carer education on assisting with exercises and preventing learned non-use
• Community reintegration and vocational rehabilitation

Phase 3 — Long-Term Lifestyle Modification (Secondary Prevention)

Summary Framework

NON-PHARMACOLOGICAL TREATMENT OF STROKE
│
├── ACUTE PHASE
│   ├── Mechanical thrombectomy (large vessel occlusion)
│   ├── Carotid endarterectomy / stenting
│   ├── Decompressive hemicraniectomy (malignant MCA oedema)
│   ├── Temperature control (surface cooling)
│   ├── Airway management & positioning
│   └── Mechanical DVT prophylaxis (compression stockings)
│
├── REHABILITATION PHASE
│   ├── Stroke unit care (multidisciplinary team)
│   ├── Physiotherapy — motor recovery, gait
│   ├── Occupational therapy — ADLs
│   ├── Speech therapy — aphasia, dysphagia
│   ├── Constraint-induced movement therapy
│   ├── Swallowing assessment & nutrition support
│   ├── Neuromodulation (TMS, tDCS) — investigational
│   ├── Robotic therapy — investigational
│   └── Psychological support / post-stroke depression
│
└── SECONDARY PREVENTION (Lifestyle)
    ├── Smoking cessation
    ├── Aerobic exercise ≥150 min/week
    ├── DASH/Mediterranean diet
    ├── Weight reduction
    ├── Alcohol restriction
    ├── Sleep apnoea treatment (CPAP)
    └── Glycaemic control through diet

Key principle: Stroke unit care + early multidisciplinary rehabilitation is among the most powerful non-pharmacological interventions available — with outcome benefits equivalent to or exceeding most individual drug therapies. — Harrison's Principles of Internal Medicine 22E