A Case of Posterior Reversible Encephalopathy Syndrome Presenting as Obstructive Hydrocephalus

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiographic disorder classically consisting of subcortical edema bilaterally in the cerebral hemispheres. Extensive white matter hyperintensities are observed typically in the occipital and parietal regions on T2 weighted imaging without diffusion restriction (1). Cases of predominant brainstem involvement, without the classic aforementioned subcortical involvement, are uncommon (2,3) with one study estimating it to comprise 4% of those diagnosed with PRES (2). We present a rare case of brainstem PRES who presented with obstructive hydrocephalus and signs of raised intracranial pressure (4, 5).