Makindo Medical Notes

🧠 Watershed infarcts occur in the border zones between two or more cerebral arterial territories. These regions are particularly vulnerable to hypoperfusion 🌊, especially during systemic hypotension or severe carotid disease. 💡 They account for ~10% of all ischemic strokes.

📖 About

• 🧩 Found at junctions of major arteries (ACA, MCA, PCA).
• Two main types: Cortical Border-Zone (CBZ) & Internal Border-Zone (IBZ).
• Pathophysiology: ↓ cerebral perfusion ± microemboli.

⚠️ Aetiology

• Severe systemic hypotension (e.g. shock, perioperative drops).
• Carotid artery stenosis or occlusion.
• 💉 Microemboli contributing to cortical infarcts.

🗺️ Cortical Border-Zone Infarcts

• Between distal ACA–MCA–PCA territories.
• Wedge-shaped infarcts in parietal/frontal cortex.
• Often unilateral, linked to hypoperfusion or emboli.

🏞️ Internal Border-Zone Infarcts

• Between cortical vessels & deep perforators (lenticulostriate, Heubner).
• Often due to profound hypotension or severe carotid/MCA stenosis.
• Appear as linear/band-like lesions parallel to lateral ventricles.

🧩 Risk Factors

• Rapid BP reduction in hypertensives.
• Perioperative hypotension 🛠️.
• Shock (cardiac arrest, sepsis, dehydration).
• Severe carotid stenosis.
• Low cardiac output (e.g. heart failure).

🩺 Clinical Presentation

• Varies by cortical/subcortical area affected.
• Common: weakness/paralysis, sensory loss, visual field defects, aphasia.
• “Man-in-the-barrel” syndrome 🧍‍♂️: proximal upper & lower limb weakness > distal.

🔬 Investigations

• 🧪 Bloods: FBC, U&E, LFTs, glucose, cardiac enzymes, lactate.
• 🖥️ Imaging: MRI-DWI (gold standard), CT, CTA/MRA.
• 🩻 Carotid duplex for stenosis, echo for embolic source, ECG for arrhythmias.

💊 Management

• 💧 Restore perfusion: cautious BP optimisation, fluids for hypovolaemia.
• 🫀 Treat underlying cause: carotid revascularisation, cardiac management.
• 🛡️ Secondary prevention: antiplatelets, statins, BP control, lifestyle modification.
• 🧑‍⚕️ Rehabilitation: physio, OT, speech therapy as needed.

📈 Prognosis

• Outcome depends on infarct size & speed of perfusion restoration.
• Early rehab improves recovery 💪.

📚 References

• Caplan LR, Hennerici M. Arch Neurol. 1998;55(11):1475-1482.
• Derdeyn CP, Powers WJ. In: Barnett's Stroke, 5th ed. Elsevier Saunders; 2011.
• Bladin CF, Chambers BR. Stroke. 1993;24(12):1925-1932.