Posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a subacute condition characterised by a variety of neurological manifestations, most commonly visual disturbances, seizures, and altered consciousness. Despite its name, the syndrome is not invariably reversible, and the radiological lesions indicative of vasogenic oedema may occur in several brain regions rather than being confined to the posterior cerebral hemispheres. The most frequently affected areas are the dorsal parieto-occipital regions, with white matter always being more severely affected than the cortex. The underlying pathophysiology is based on endothelial dysfunction, most commonly resulting from a rapid increase in blood pressure that exceeds the upper limit of cerebral autoregulation. However, approximately 20% of cases occur in normotensive patients. In such cases, endothelial injury is thought to be mediated by circulating cytokines released in response to direct endothelial damage caused by drugs, toxins, or various systemic diseases. Successful treatment and the potential reversibility of the syndrome depend on prompt diagnosis and immediate therapeutic intervention. Management is directed toward the underlying pathogenic mechanism and may include blood pressure control or withdrawal of the offending drug or toxin. In addition to therapeutic approaches, this review also discusses the clinical course and prognosis of the disease.