Isolated Infratentorial Posterior Reversible Encephalopathy Syndrome (PRES) in Nephrotic Syndrome: A Case Report.

We present a case of infratentorial variant posterior reversible encephalopathy syndrome (PRES), which is a very rare presentation of PRES. Atypical PRES is more common than the typical parieto-occipital PRES. We present a 43-year-old male who presented with acute change in mentation, left gaze deviation, and paraparesis with initial blood pressures of 230/120 with anasarca. In the present admission, his CT showed diffuse infratentorial hypodensity. Computed tomography angiography (CTA) was negative for large vessel occlusion. MRI of the brain without contrast showed fluid-attenuated inversion recovery (FLAIR) change diffusely in the brainstem but also extended to the cerebellum and occipital lobe, along with diffusion restriction seen in different regions, including the brainstem and cortex. The patient improved clinically with the improvement of blood pressure and follow-up imaging in five weeks showed improvement of imaging findings. This presentation helps understand the approach to patients presenting with brainstem edema in the acute phase.