Posterior Reversible Encephalopathy (PRES) As a Presentation Form of Classical Polyarteritis Nodosa (PAN)

A 21-year-old woman with unremarkable past health presented with an intense headache and visual disturbance, followed by a secondary generalized tonic-clonic focal seizure. She had a history of arthritis, livedo reticularis, myalgia, elevated erythrocyte sedimentation rate, and nonspecific constitutional manifestations (fever and weight loss). Examination revealed new-onset severe hypertension. Complete immunological studies were negative. Electroencephalogram showed abnormalities compatible with secondarily generalized tonic–clonic focal occipital seizures. Brain magnetic resonance imaging (MRI) revealed high signal intensity on T2 in occipital lobes, cerebellum, and brainstem and renal imaging multiple hypoenhancing parenchymal images (renal infarction). Follow-up brain MRI at 3 months showed marked improvement. A diagnosis of polyarteritis nodosa with posterior reversible encephalopathy syndrome was made.