SCRN Anatomy, Physiology, and Pathophysiology of Stroke 2 — Questions and Answers
Question 1: Which cerebral artery supplies the lateral surface of the frontal and parietal lobes, including the primary motor cortex of the upper extremity?
- Anterior cerebral artery
- Middle cerebral artery (Correct answer)
- Posterior cerebral artery
- Basilar artery
Correct answer: Middle cerebral artery
The middle cerebral artery (MCA) supplies the lateral hemispheres including the motor and sensory cortex for the face, arm, and hand.
Question 2: A patient presents with bilateral leg weakness and urinary incontinence after a stroke. Which artery territory is most likely affected?
- Middle cerebral artery
- Posterior cerebral artery
- Anterior cerebral artery (Correct answer)
- Posterior inferior cerebellar artery
Correct answer: Anterior cerebral artery
The anterior cerebral artery (ACA) supplies the medial hemisphere including the leg area of the motor cortex; bilateral ACA involvement causes bilateral leg weakness and incontinence.
Question 3: During cerebral ischemia, the ischemic penumbra is best defined as:
- Irreversibly infarcted tissue at the stroke core
- Hypoperfused but potentially viable tissue surrounding the infarct core (Correct answer)
- The zone of reactive hyperemia following reperfusion
- Necrotic tissue resulting from hemorrhagic transformation
Correct answer: Hypoperfused but potentially viable tissue surrounding the infarct core
The ischemic penumbra is electrically silent but metabolically viable tissue surrounding the infarct core that can be salvaged with timely reperfusion.
Question 4: Which ion flux occurs first during the depolarization phase of ischemic neuronal injury?
- Potassium efflux
- Sodium influx (Correct answer)
- Chloride efflux
- Magnesium influx
Correct answer: Sodium influx
During ischemic depolarization, failure of the Na⁺/K⁺-ATPase pump leads to massive sodium influx, followed by water entry and cytotoxic edema.
Question 5: Lacunar infarcts are most commonly caused by:
- Cardioembolism from atrial fibrillation
- Large artery atherosclerosis of the carotid bifurcation
- Lipohyalinosis of small penetrating arteries (Correct answer)
- Venous thrombosis of the superior sagittal sinus
Correct answer: Lipohyalinosis of small penetrating arteries
Lacunar infarcts result from lipohyalinosis or microatheroma of small penetrating arteries (< 15 mm diameter), most commonly in the basal ganglia, thalamus, and internal capsule.
Question 6: A 58-year-old patient develops sudden onset diplopia, dysphagia, and ipsilateral facial numbness with contralateral body numbness. Which syndrome does this represent?
- Weber syndrome
- Wallenberg (lateral medullary) syndrome (Correct answer)
- Benedikt syndrome
- Millard-Gubler syndrome
Correct answer: Wallenberg (lateral medullary) syndrome
Wallenberg syndrome results from posterior inferior cerebellar artery occlusion causing ipsilateral facial and contralateral body pain/temperature loss, dysphagia, dysarthria, and Horner syndrome.
Question 7: Which mechanism accounts for the majority of hemorrhagic strokes in elderly hypertensive patients?
- Rupture of a saccular (berry) aneurysm
- Arteriovenous malformation rupture
- Hypertensive lipohyalinosis with vessel rupture (Correct answer)
- Cerebral amyloid angiopathy
Correct answer: Hypertensive lipohyalinosis with vessel rupture
Chronic hypertension causes lipohyalinosis of small penetrating vessels, making them prone to rupture and causing intracerebral hemorrhage, typically in the basal ganglia, thalamus, pons, or cerebellum.
SCRN Anatomy, Physiology, and Pathophysiology of Stroke 2
Which cerebral artery supplies the lateral surface of the frontal and parietal lobes, including the primary motor cortex of the upper extremity?