Evolution of venous-pattern brain injury in early infantile parechovirus encephalitis: A serial MRI study from onset to recovery – a case report

Human parechovirus is a major cause of encephalitis in the neonatal and early infantile periods, with the white matter frequently reported as the primary site of pathology. However, the mechanisms underlying the development of these lesions are poorly understood. A female infant with an uneventful prenatal and perinatal history developed a fever on day of life 34. From illness day 2, she experienced clustered seizures, which resolved by day 7. A cerebrospinal fluid (CSF) polymerase chain reaction confirmed the diagnosis of parechovirus encephalitis. Brain magnetic resonance imaging (MRI) revealed multiple areas of reduced apparent diffusion coefficient (ADC) and diffuse white matter abnormalities. During the clinical course, a distinct pattern emerged in which the anterior white matter showed T2 hypointensity, while the posterior white matter exhibited T2 hyperintensity. At the 6-month follow-up, no significant neurological abnormalities were noted. MRI findings in this case can be explained by dysfunction of the cerebral venous system. These observations suggest that the white matter abnormalities observed in parechovirus encephalitis may be of venous origin.