Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome Associated With Relugolix Therapy for Giant Uterine Fibroids and Anemia: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition characterized by reversible vasogenic edema. Reversible cerebral vasoconstriction syndrome (RCVS) is a disorder characterized by segmental narrowing of the cerebral arteries that causes severe headaches. We report a case of PRES and RCVS development in a 52-year-old woman treated with a gonadotropin-releasing hormone antagonist, relugolix, and oral iron supplementation for uterine fibroids and iron deficiency anemia. In this case, relugolix may have contributed to the onset of PRES and RCVS through estrogen suppression and the resulting endothelial dysfunction. Additionally, gradual treatment of anemia over two months with oral iron alone may have played a role in this case, given that increased intravascular volume and viscosity can precipitate vascular injury and vasoconstriction. To our knowledge, this represents the first reported case of concurrent PRES and RCVS associated with relugolix therapy.