PRES is an uncommon condition characterized by any of the following: altered mental status, seizure, visual disturbance, and headache, in the setting of vasogenic edema, not due to mass lesion. Several conditions have been associated with PRES, including hypertension (HTN), eclampsia, autoimmune conditions, sepsis, certain chemotherapeutic and immunosuppressant medications, and renal disease.
The mechanism of PRES remains unclear, with two predominant hypotheses. The first postulates inflammation causing endothelial dysfunction, leading to vasoconstriction and subsequently hypoperfusion of arterioles, resulting in disruption of the blood-brain barrier. The second theory postulates impaired cerebral autoregulation, due to excessively elevated blood pressure. Hyperperfusion leads to cerebral vessel damage, which then results as endothelial dysfunction and vasogenic edema. Increased inflammatory cytokines in chronic obstructive pulmonary disease (COPD) may affect endothelial function, predisposing to development of PRES.