NEURO 25: Stroke

1. Pathophysiology of Ischemic & Hemorrhagic Stroke (IS, HS)

Think of a stroke as a brain attack where blood flow is disrupted, leading to brain damage.

🧠 Ischemic Stroke (IS) (85% of strokes)

• Cause: A clot blocks blood flow to part of the brain.

• Analogy: Imagine a clogged pipe stopping water from reaching a plant, and the plant starts to wilt. That’s what happens to brain cells—they die if they don’t get oxygen!

• Main causes (TOAST classification):

  • Large artery atherosclerosis (plaque buildup)

  • Small artery disease (lacunar strokes)

  • Cardioembolism (clots from the heart, e.g., in AFib)

  • Cryptogenic strokes (mystery strokes, unknown cause)

  • Other causes (e.g., arterial dissection)

🧠 Hemorrhagic Stroke (HS) (15% of strokes)

• Cause: A blood vessel bursts, leading to bleeding in the brain.

• Analogy: Instead of a clogged pipe, imagine a burst pipe flooding the area. Blood irritates brain tissue and increases pressure, causing damage.

• Types:

  • Intracerebral Hemorrhage (ICH): Bleeding directly into the brain.

  • Subarachnoid Hemorrhage (SAH): Bleeding into the space around the brain, usually from an aneurysm.

💡 Key takeaway: Ischemic = clot blocks oxygen; Hemorrhagic = vessel bursts and leaks blood. Both lead to brain cell death but in different ways.

2. Signs & Symptoms of IS and HS

🚨 FAST is the classic way to recognize a stroke:

• Face drooping

• Arm weakness

• Speech difficulty

• Time to call 911

Other symptoms:

• Ischemic Stroke: Sudden numbness, confusion, trouble walking, vision issues.

• Hemorrhagic Stroke: Sudden severe headache ("worst headache of my life"), nausea, vomiting, loss of consciousness, seizures.

💡 BIG difference: Hemorrhagic strokes often have a thunderclap headache, while ischemic strokes are more about weakness and slurred speech.

3. Diagnostic Criteria of IS vs. HS

The key test = CT scan!

• Ischemic Stroke: Appears dark (hypodense) on CT (since it’s a lack of blood supply).

• Hemorrhagic Stroke: Appears bright (hyperdense) due to bleeding.

• Other tests: CT angiography (to look at blood vessels), MRI (better for small strokes), ECG (to check for AFib), blood tests (rule out mimics like hypoglycemia).

💡 CT is done ASAP because treating ischemic stroke with blood thinners could be deadly if it’s actually a hemorrhagic stroke.

4. Goals of Therapy for IS & HS

• Prevent death & disability

• Minimize brain damage

• Restore blood flow in IS or stop bleeding in HS

• Prevent future strokes (secondary prevention)

• Control blood pressure & risk factors

5. Hyperacute Management of IS (within the first hours!)

🕒 Time = brain! The faster you treat, the better the outcome.(WITHIN 24 HOURS OF ONSET)

🩸 Ischemic Stroke (IS): Remove the clot!

1. Thrombolysis (clot-busting drugs) within 4.5 hours of onset.

   • Alteplase (tPA) 0.9mg/kg

   • Tenecteplase (TNK) single bolus: 0.25mg/kg

   • Risks? Bleeding! Need to rule out hemorrhage first.

** NO blood thinners (antiplatelet OR anticoagulation) within 24 hours of thrombolysis and before repeat CT head

• NIHSS done for 48-72 hours before and after thrombolysis

1. Endovascular Therapy (EVT) / Mechanical Thrombectomy

   • Physically removes the clot using a catheter.

   • Best for large artery blockages up to 24 hours after symptoms start.

     • CRITERIA:

       • 18 years or older

       • Clot is visible on CT-A and accessible

       • Pre-stroke Modified Rankin Score 0-1

       • NIHSS of 6 or greater

💡 Key timing rules:

• If < 4.5 hours = tPA (clot-busting drug).

• If < 24 hours + large clot = EVT (catheter to remove clot).

BLOOD PRESSURE CONTROL

1. If eligible for thrombolysis:

   1. 185/110 mmHg x 24 hours

2. If ineligible for thrombolysis:

   1. <220 mmHg

**Avoid quickly reducing blood pressure —> lower by only ~15% in first 24 hours

6. Acute Management of IS (first 24-48 hours)

👩‍⚕ Ischemic Stroke (IS):

• Antiplatelets (to prevent new clots)

  • ASA (Aspirin) + Clopidogrel for 21 days, then ASA alone.

    • ASA 160-325 mg STAT, 80-325 mg daily

  • DAPT trials (CHANCE, POINT) show dual therapy is better than aspirin alone.

    • DAPT reduces risk of stroke in first 90 days

    • Higher risk of major hemorrhage at 90 days

    • Moderate-severe risk of bleeding

• Statins for LDL < 1.8 mmol/L (aggressive lipid control).

7. Secondary Prevention (Long-Term Prevention of IS )

🚀 Goal: Prevent another stroke!

✅ For ISCHEMIC stroke:

• Antiplatelet SAPT therapy (ASA or clopidogrel)

• Blood pressure control (target <140/90 mmHg; <130/80 if diabetic/lacunar stroke).

  • Perindopril 4 mg daily + Indapamide 2.5 mg daily

    • ACEI/ARB + Thiazide diuretic or CCB

• Lipid lowering (statin, LDL <1.8 mmol/L).

  • Atorvastatin 80 mg daily

  • Rosuvastatin 40 mg daily

    • Can add Ezetimibe or PCSK9i

• Anticoagulation if due to AFib (DOAC > Warfarin).

  • Restarting therapy:

    • TIA = 1 day

    • Small, non-disabling infarct = 3 days

    • Moderate stroke = 6 days

    • Large stroke = 12 days

• Lifestyle: Stop smoking, Mediterranean diet, exercise, manage diabetes.

7. HEMORRHAGIC STROKE

1) ABCs

2) Screening for surgical intervention

3) STOP/REVERSAL of causative agents (antiplatelet, anticoagulant)

• Warfarin = Vit K

• Dabigatran - Idarucizumab

• Rivaroxaban, Apixaban, Edoxaban = Andexanet alfa

• Heparin = Protamine Sulfate

• LMW Heparin = Andexanet alfa OR Protamine Sulfate

• Fondaparinux = Andexanet alfa

4) Blood pressure stabilization

• Target <140-160 for first 24-48 hours post ICH

• Parenteral labetolol, hydralazine, nicardapine, enalapril

Restarting anticoagulation:

• Start after repeat CT-H and consult with neurology

💡 Summary of Key Takeaways!

• Ischemic = clot, Hemorrhagic = burst vessel.

• CT scan immediately to differentiate!

• Ischemic stroke = thrombolysis (tPA) + thrombectomy if eligible.

• Hemorrhagic stroke = control bleeding & BP (<140 mmHg).

• Secondary prevention = BP, cholesterol, blood thinners (only for IS)