A condition that is characterized by HEADACHE; SEIZURES; and visual loss with edema in the posterior aspects of the CEREBRAL HEMISPHERES, such as the BRAIN STEM. Generally, lesions involve the white matter (nerve fibers) but occasionally the grey matter (nerve cell bodies). The disease is Posterior Leukoencephalopathy Syndrome (EFO_1001829). Also known as: PRES, RPLS, posterior reversible encephalopathy syndrome, reversible posterior leukoencephalopathy syndrome.