Cytokine/chemokine overproduction in parechovirus type 3 encephalitis with bilateral hippocampal lesions: A pediatric case report

Parechovirus type 3 (PeV-3) presents with sepsis-like syndrome in neonates and young infants. PeV-3 has neurotropism and occasionally causes encephalitis. We evaluated the cytokine/chemokine profile in the cerebrospinal fluid of a young infant with PeV-3 encephalitis. The patient was a 1-month-old boy who developed fever, loss of consciousness, and seizures. On admission (2nd day of illness), no abnormalities were found on MRI. Thereafter, head MRI on the 4th day revealed abnormal intensities in the white matter around the bilateral lateral ventricles, corpus callosum, and bilateral hippocampus and amygdala. Although intravenous thiopental failed to stop the seizures, ketamine and phenobarbital were effective. Bilateral hippocampal lesions were unusual in HPeV-3 encephalitis and considered to be caused by super-refractory status epilepticus, indicating the strength of the disease. PeV-3 was detected in the blood, cerebrospinal fluid, nasal discharge, and fecal samples upon admission. The cytokine and chemokine levels in the cerebrospinal fluid were significantly elevated. Characteristically, neopterin levels in the cerebrospinal fluid increased as the white matter lesions appeared. These results suggested that cytokine/chemokine overproduction may be deeply involved in the pathology of the PeV-3 encephalitis. Although super-refractory status epilepticus and cytokine/chemokine overproduction indicated the strength of the disease, our patient was discharged without neurological sequelae and the combination of immunotherapy as well as seizure control may have contributed to the good outcome.