Posterior reversible encephalopathy is a distinctive syndrome associated with different diseases and drugs. Disease evolution is frequently favorable with an adequate treatment. Damage typically involves parietal-occipital lobes even if a more anterior diffusion has been described. Here, we report the case of a woman affected by Polyarteritis Nodosa, who suddenly complicated with decreased consciousness and seizures, during an acute hypertensive state. MRI imaging showed increased T2 and FLAIR signal in posterior regions. Her neurological evolution was positive, according to arterial pressure correction, although the systemic vasculitis was still ongoing, hence affecting final prognosis.