Unusual Aspect of Posterior Reversible Encephalopathy Syndrome in an Elderly Adult.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) classically occurs in patients presenting with a sudden increase of arterial pressure or eclampsia, but the range of etiologies is very wide. Although the mechanisms underlying PRES remain unclear, research suggests that when the extent of hypertension exceeds the threshold of cerebral blood flow autoregulation, this induces blood-brain barrier disruption that leads to brain edema. Unusual presentations on magnetic resonance imaging (MRI) are possible, including the involvement of frontal or temporal lobes, cerebellar hemispheres, basal ganglia, brainstem, or deep white matter. However, in these atypical locations, edema is mostly accompanied by the classical parieto-occipital region involvement.

CASE REPORT: We report the case of an elderly adult presenting with an unusual presentation of PRES with exclusive involvement of the frontal lobes, associated with severe hypertension. In our case, computed tomography and MRI abnormalities were exclusively localized in the frontal regions without involvement of the classical parieto-occipital regions. A favorable clinical course after hypertension management and complete clearance on an MRI scan at 3 months' follow-up confirmed the diagnosis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: PRES is a condition potentially encountered by many doctors, especially in the emergency department. However, atypical clinical or imaging presentations are possible and could delay the diagnosis. These must be known to begin adequate treatment as quickly as possible.