Stroke & TIA – Study Notes

The Historical Backdrop 

• 1995 – NINDS Trials (tPA)

  • First large RCTs on thrombolytics in stroke within 3-hour window.

  • Controversial: patient allocation issues, unclear outcome measures (modified Rankin Scale, dichotomous vs. graded outcomes).

  • Sparked debate on “what is a good outcome?” in stroke care.

• Post-1995

  • 13+ subsequent trials, mostly neutral.

  • Despite controversy, led to establishment of stroke centers and industry around tPA.

• 2015 – MR CLEAN, EXTEND-IA, ESCAPE

  • Introduced endovascular therapy: mechanical thrombectomy or intra-arterial tPA.

  • Shift from “time is brain” to neurogeographic risk–benefit analysis (core infarct vs. salvageable penumbra).

  • Advanced imaging (CT perfusion, MRI DWI) guides intervention decisions.

Types of Stroke

1. Ischemic Stroke (80–90%)

   • Thrombotic (local atherosclerotic clot).

   • Embolic (often cardiac source, e.g., atrial fibrillation).

   • Clinical presentation follows vascular distribution.

2. Hemorrhagic Stroke

   • Management differs, particularly in blood pressure targets.

Stroke Syndromes

• MCA (Middle Cerebral Artery)

  • Most common.

  • Contralateral motor/sensory deficits (face/arm > leg).

  • Facial droop spares forehead (dual innervation).

  • Contralateral hemianopsia; gaze deviation toward lesion.

• ACA (Anterior Cerebral Artery)

  • Contralateral leg > arm/face weakness & sensory loss.

• PCA (Posterior Cerebral Artery)

  • Contralateral homonymous hemianopsia, visual agnosia.

  • Minimal motor involvement.

• Vertebrobasilar System

  • Vertigo, brainstem symptoms, cranial nerve findings.

  • Can mimic peripheral vertigo → high suspicion needed.

• Lacunar Strokes

  • Small vessel disease.

  • Pure motor hemiparesis common; no sensory deficits.

TIA (Transient Ischemic Attack)

• Definition: Transient neurologic dysfunction without infarction (confirmed by imaging).

• Symptoms: Usually <30 min (often <10 min).

• Diagnosis: Imaging must show no infarct.

• Key points:

  • Loss of consciousness rarely TIA/stroke (except rare brainstem cases).

  • TIA tends to cause loss of function, not added symptoms.

  • Mimics: hypoglycemia, Todd’s paralysis, seizures, syncope, migraine.

  • ABCD2 score: no longer reliable → do not use.

ED Evaluation

• ABCDs: Airway, Breathing, Circulation, Dextrose (check glucose early).

• Physical exam: Full neuro exam, carotid bruits, cardiac rhythm.

• ECG: Identify atrial fibrillation & concurrent ACS (~5% of stroke patients).

• Head CT (non-contrast): Exclude hemorrhage before thrombolytics.

• Advanced imaging (CTA, CT perfusion, MRI DWI): Identify infarct core vs. penumbra.

Prehospital Innovations

• Mobile Stroke Units (CT-equipped ambulances):

  • Originated in Berlin (STEMO program).

  • Now in several US states.

  • Evidence: No demonstrated improvement in outcomes; very costly.

Management Principles

Blood Pressure

• Ischemic stroke:

  • Do NOT treat unless >220/120 mmHg.

  • If candidate for tPA: must be <185/110 mmHg.

  • Preferred IV agents: Nicardipine, clevidipine.

  • Oral ACE inhibitors (e.g., lisinopril) for long-term control.

• Hemorrhagic stroke:

  • Lower systolic BP to 160–180 mmHg.

  • Nicardipine/clevidipine preferred.

Thrombolysis

• tPA (alteplase): Standard for eligible patients.

• Tenecteplase (TNK): Emerging evidence of superiority in some settings.

• ~6% risk of intracranial hemorrhage.

• Requires informed consent; discuss risks vs. benefits.

Endovascular Therapy

• Large vessel occlusion:

  • Thrombectomy shown to improve outcomes (MR CLEAN, EXTEND-IA, ESCAPE).

  • Some trials show benefit without prior tPA.

  • Trend mirrors MI treatment evolution (thrombolysis → PCI).

Epidemiology

• Stroke Belt: Southeastern US with higher stroke mortality.

  • Contributing factors: poverty, reduced access to care, primary care shortages, comorbidities.

Key Takeaways

• Stroke care has evolved from time-only to tissue-based, neurogeographic decision-making.

• Always rule out mimics (especially hypoglycemia).

• Imaging now defines salvageable tissue and guides intervention.

• BP management differs for ischemic vs. hemorrhagic stroke.

• Endovascular therapy is the frontier, shifting stroke care toward an MI-like model.

• Stroke/TIA remains a dynamic field with rapidly evolving evidence and guidelines.