Pearls & Oy-sters: Iatrogenic relative hypotension leading to diffuse internal borderzone infarctions and coma

Abstract

Pearls & Oy-sters: Iatrogenic relative hypotension leading to diffuse internal borderzone infarctions and coma PEARLS• Isolated hypoperfusion is more likely to cause internal borderzone infarcts and less likely to cause cortical borderzone infarcts.• Cortical borderzone infarction should raise suspicion for an embolic etiology.• Diffuse subcortical infarcts from hypoperfusion can lead to poor neurologic outcome. OY-STER• Patients who present with severe hypertension should have their blood pressure initially lowered by no more than 25% to reduce the chance of cerebral, coronary, or renal ischemia.CASE REPORTS We present 2 patients with hypertensive emergency who developed extensive watershed infarcts after their blood pressure was rapidly lowered.The first patient was a 50-year-old man admitted to an outside hospital with shortness of breath and an initial blood pressure of 204/108 mm Hg. He was diagnosed with hypertensive emergency and started on IV nicardipine drip, which dropped his blood pressure to 102/66 mm Hg within a few minutes. His blood pressure remained in this range for 2 hours, and he became unarousable. Attempts were made to increase his blood pressure with fluids though his level of consciousness did not improve. MRI diffusion-weighted imaging (DWI) subsequently revealed numerous infarcts in the bilateral internal borderzone (IBZ) (figure, A). Vascular imaging revealed intracranial atherosclerosis with moderate narrowing of multiple arteries. He was transferred to our hospital for further care, and remained in a vegetative state until discharge on hospital day 74.The second patient was a 41-year-old man who presented to the hospital with chest pain and was found to have a descending aortic dissection with a blood pressure of 235/144 mm Hg. An IV nicardipine drip was initiated to prevent extension of the dissection, and the patient became unarousable when the blood pressure dropped to 114/52 mm Hg, where it remained for approximately 3 hours. Subsequent MRI DWI revealed numerous foci of IBZ and corpus callosum infarctions, seen in the figure, B. Carotid ultrasound studies did not reveal any significant stenosis in the external or internal carotid arteries. Follow-up imaging performed 2 months after the initial imaging showed the expected evolution of the known infarcts with no new infarcts noted. The patient died on hospital day 86 without regaining consciousness.DISCUSSION Watershed strokes comprise approximately 10% of all ischemic strokes and are characterized by infarction localized to the borderzones between major vascular territories in the brain. Watershed strokes can occur in the IBZ or cortical borderzone (CBZ), seen in the figure, C. The cortical borderzones are located at the junctions of the distal branches of the anterior, middle, and posterior cerebral artery territories. Internal borderzones are located at the junctions of the distal branches of the anterior, middle, and posterior cerebral artery territories with the deep perforating arteries, including the lenticulostriate arteries...

Neuroimaging mimics of anoxic brain injury: A review

“…4 States with preserved oxygenation but impaired perfusion result in a border zone (or watershed) distribution of ischemia affecting predominantly the deep white matter of the corona radiata and sometimes the cortical border zones, although isolated cortical border zone infarction should raise suspicion for an embolic etiology. 5 In contrast, states of poor oxygenation with relatively preserved perfusion (eg, carbon monoxide poisoning) selectively injure the populations of cells most susceptible to metabolic insult. 3 The typical pattern of imaging findings in patients with anoxic brain injury is driven by the selective vulnerability of different cell populations to injury.…”