A 66-year-old man suffers prolonged hypotension during emergency laparotomy. On waking he has weakness of both arms with relative sparing of the legs, and sensory loss in a cape-like distribution over the shoulders. MRI shows infarction in the border zone between the anterior and middle cerebral artery territories bilaterally. This pattern of infarction results from which mechanism?
- A Hypoperfusion at the distal fields of two adjacent arterial territories ✓
- B Cardioembolic showering to distal cortical branches
- C Venous sinus thrombosis with venous infarction
- D Occlusion of a single lenticulostriate perforator
Correct answer: A. Hypoperfusion at the distal fields of two adjacent arterial territories
Explanation
Watershed or border-zone infarcts occur at the junctions between the terminal territories of major cerebral arteries, where perfusion pressure is lowest. Systemic hypotension, cardiac arrest, or critical carotid stenosis preferentially injures these zones, classically producing bilateral arm weakness with facial and leg sparing, the so-called person-in-a-barrel distribution. Emboli lodge in cortical branches rather than border zones, and single perforator occlusion gives a small deep lacunar infarct.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.