SEP 26, 2008
The authors of the current study describe the case of a 31-year-old woman who developed bilateral posterior ischemic optic neuropathy (PION) and cerebral border zone and anterior (thoracic) spinal cord area watershed infarcts after dramatic correction of malignant hypertension. The case was supported by full clinical and neuroimaging documentation. The authors concluded that all three infarctions were the result of autoregulatory failure in the face of relative hypotension.
The patient had presented with severe systemic hypertension (270/120 mm Hg) and anemia (hematocrit of 27.1 percent). She was given agents that lowered her blood pressure to 120/80 mm within one day. This relative hypotension and subsequent autoregulatory failure produced widespread watershed infarcts of the sort that are seen after long spinal cord surgeries complicated by anemia and hypotension and that have been associated with PION.
This article provides several interesting take-home points in addition to the obvious management issue that practitioners should take care not to lower blood pressure too dramatically in malignant hypertension patients. The optic nerves, anterior spinal cord, and grey/white cerebral border zone seem to share a special vulnerability to this type of watershed infarct often associated with hypotension and anemia. There are upper and lower limits to systemic blood pressure that exceed the capacity for autoregulation, especially in these tissues.
Dr. Sadun is a consultant to Allergan, Inc., and Pfizer Ophthalmics.