A 58-year-old man with hypertension and diabetes presents with acute left-sided weakness and speech difficulty. MRI brain shows an acute infarct in the left middle cerebral artery (MCA) territory. Which feature best distinguishes cardioembolic stroke from atherothrombotic stroke in this patient?

Explanation

## Distinguishing Cardioembolic from Atherothrombotic Stroke ### Key Clinical Features **Key Point:** Cardioembolic stroke classically presents with sudden onset and maximal neurological deficit at presentation, whereas atherothrombotic stroke typically shows gradual onset with stepwise progression over hours. ### Comparison Table | Feature | Cardioembolic Stroke | Atherothrombotic Stroke | | --- | --- | --- | | **Onset** | Sudden, maximal at presentation | Gradual, stepwise over hours | | **Progression** | Maximal immediately | Progressive worsening | | **Location** | Cortical, embolic distribution (MCA > ACA > PCA) | Lacunar or large vessel territory | | **Prodrome** | Absent | TIA or stuttering symptoms common | | **Risk factors** | Atrial fibrillation, cardiac disease, valvular disease | Hypertension, diabetes, smoking, hyperlipidemia | | **Recurrence** | Higher early recurrence risk | Lower early recurrence | ### Pathophysiological Basis **High-Yield:** Cardioembolic strokes occur when a thrombus from a cardiac source (AF, MI, valvular disease) lodges in a cerebral artery, causing sudden occlusion. The deficit is maximal immediately because the vessel is suddenly blocked. In contrast, atherothrombotic strokes develop gradually as atherosclerotic plaque progressively narrows a vessel, allowing time for collateral circulation to develop. Symptoms may fluctuate as the thrombus forms and partially dissolves (TIA-like episodes). ### Clinical Pearl **Clinical Pearl:** A patient with acute stroke presenting with sudden onset of maximal deficit and a history of atrial fibrillation or recent MI should raise suspicion for cardioembolic stroke. Conversely, a patient with gradual symptom onset and a history of TIAs is more consistent with atherothrombotic disease. ### Diagnostic Implications **Tip:** On examination, cardioembolic strokes often present with cortical signs (aphasia, neglect, visual field defects) because emboli preferentially lodge in cortical branches of the MCA. Atherothrombotic strokes more commonly cause lacunar syndromes or pure motor/sensory deficits.