Idiopathic Posterior Reversible Encephalopathy Syndrome (PRES) in a 4-Month-Old Infant: A Case Report

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico–radiological syndrome characterized by acute neurological manifestations related to reversible vasogenic cerebral edema. Although increasingly recognized in pediatric populations, it remains exceptionally rare in infants younger than six months, in whom the diagnosis may be particularly challenging. We report the case of a 4-month-old infant with no significant medical history admitted for recurrent generalized tonic-clonic seizures in an afebrile context. Initial clinical, biological, and cranial computed tomography assessments were unremarkable. Brain MRI revealed imaging features consistent with PRES. An extensive etiological workup, including metabolic, infectious, autoimmune, and toxicological investigations, was negative, supporting the diagnosis of idiopathic PRES. The patient responded favorably to antiepileptic therapy, with no recurrence of seizures. This case underscores the importance of considering PRES in the differential diagnosis of seizures in early infancy, even in the absence of identifiable risk factors.