stroke

 The five major etiologies of ischemic stroke, particularly of embolic and thrombotic origin, can be categorized according to source or mechanism. Here's a structured breakdown using your starting framework and standard stroke classification schemes (like TOAST):

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1. Cardioembolic Stroke

• Emboli originate in the heart.

• Common causes:

  • Atrial fibrillation (most common)

  • Infective endocarditis (vegetations)

  • Valvular heart disease (e.g., rheumatic mitral stenosis)

  • Mechanical prosthetic valves

  • Left ventricular thrombus (e.g., post-MI or cardiomyopathy)

  • Patent foramen ovale (PFO) or atrial septal defect (ASD) with paradoxical embolism

  • Cardiac tumors (e.g., atrial myxoma)

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2. Large Artery Atherosclerosis (Extracranial or Intracranial)

• Thrombotic or artery-to-artery embolic stroke due to atherosclerotic plaque rupture or stenosis.

• Includes:

  • Extracranial: Carotid bifurcation plaque rupture or occlusion

  • Intracranial: Atherosclerosis of MCA, ACA, PCA, basilar, vertebral arteries

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3. Small Vessel Disease (Lacunar Stroke)

• Due to lipohyalinosis or microatheroma in small penetrating arteries.

• Affects:

  • Lenticulostriate arteries (to basal ganglia)

  • Thalamoperforating arteries

  • Common in chronic hypertension, diabetes, and aging

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4. Stroke of Other Determined Etiology

• Less common but identifiable causes, including:

  • Aortic arch atheroma (e.g., ulcerated plaque)

  • Hypercoagulable states (antiphospholipid syndrome, cancer)

  • Arterial dissection (carotid or vertebral)

  • Vasculitis or autoimmune arteriopathies

  • Moyamoya disease

  • Septic emboli (from endocarditis, often affecting MCA territory)

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5. Cryptogenic Stroke (Embolic Stroke of Undetermined Source - ESUS)

• No clear etiology identified after standard workup (CTA/MRA, echo, telemetry).

• Common considerations:

  • Paroxysmal AF (missed on short-term monitoring)

  • PFO/ASD (paradoxical embolism)

  • Aortic arch plaques

  • Occult malignancy or thrombophilia

  • Nonbacterial thrombotic endocarditis (e.g., Libman-Sacks)

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Summary Table

Etiology	Mechanism	Examples
1. Cardioembolic	Embolus from heart	AFib, endocarditis, PFO, valve disease
2. Large artery atherosclerosis	Artery-to-artery embolism or thrombus	Carotid plaque, intracranial stenosis
3. Small vessel disease	Lipohyalinosis / microatheroma	Lacunar infarcts (HTN, DM)
4. Other determined causes	Varied (dissection, vasculitis, etc)	Moyamoya, aortic plaques, septic emboli
5. Cryptogenic (ESUS)	Unknown	PFO, occult AF, hypercoagulable states