Human Parechovirus Encephalitis As an Important Differential Diagnosis of White Matter Lesions in Neonatal Sepsis-Like Illness

Human parechoviruses (HPeVs) are a family of neurotropic viruses that may cause central nervous system infection in the neonatal period, resulting in white matter lesions with a large spectrum of neurological symptoms. Common clinical presentations of infections with HPeV type 3 (HPeV3) are seizures, apnea, irritability, and lethargy. We report on a case of neonatal HPeV encephalitis, diagnosed on the basis of magnetic resonance image (MRI) findings and HPeV3 polymerase chain reaction (PCR). At the age of 4 weeks, the previously healthy infant presented with recurrent severe apnea, lethargy, and mild diarrhea. The child was irritable with the clinical symptoms of a sepsis-like neonatal infection, requiring mechanical ventilation for 7 days. Diagnostic work-up with C-reactive protein, enterovirus PCR, and metabolic tests revealed no abnormalities. CSF protein levels were elevated. MRI at the fourth day of illness revealed diffuse signal intensity changes of the white matter with multiple punctate lesions. The diffusion-weighted images showed areas of restricted diffusion in the periventricular and subcortical white matter, in particular, the frontal white matter, but also the corpus callosum, internal capsule, part of the thalamus, and pyramidal tracts of the brain stem without enhancement after contrast. The pattern of MRI involvement was suggestive of parechovirus encephalitis. HPeV3 PCR was positive in nasopharyngeal swap and stool samples. The infant gradually improved and was discharged on day 18, but developed hemiparesis with a lower limb predominance. HPeV3 should be suspected in neonates with clinical presentation of sepsis-like illness, apnoe, and CNS involvement and tested negative for enteroviruses.