Human Parechovirus Meningoencephalitis: Neuroimaging in the Era of Polymerase Chain Reaction–Based Testing

Abstract

Human parechovirus infection is an increasingly recognized cause of neonatal meningoencephalitis. We describe characteristic clinical features and brain MR imaging abnormalities of human parechovirus meningoencephalitis in 6 infants. When corroborated by increasingly available polymerase chain reaction-based testing of the CSF, the distinctive MR imaging appearance may yield a specific diagnosis that obviates costly and time-consuming further clinical evaluation. In our study, infants with human parechovirus presented in the first 35 days of life with seizures, irritability, and sepsis. MR imaging consistently demonstrated low diffusivity within the thalami, corpus callosum, and subcortical white matter with a frontoparietal predominance. T1 and T2 shortening connoting white matter injury along the deep medullary veins suggests venous ischemia as an alternative potential pathogenetic mechanism to direct neuroaxonal injury.

Brain MR Imaging of Patients with Perinatal Chikungunya Virus Infection

“…19 The main differential diagnoses for neonatal brain CHIKV infection in the acute phase are rotavirus and parechovirus infections, which have similar imaging patterns, though most cases of rotavirus encephalitis are asymptomatic. 20,21 In the case series of Sarma et al 21 of neonatal parechovirus meningoencephalitis, 1 patient underwent a longitudinal follow-up at 3 months and did not present with cystic lesions. This finding is in marked contrast to those of our patients with perinatal chikungunya.…”

“…However, other authors described the development of extensive cystic leukomalacia at the 4-month follow-up in a patient with parechovirus infection. 21 Some data suggest that preterm neonates are at higher risk of severe cystic leukoencephalomalacia in parechovirus infection. 21 Whether prematurity is also a risk factor for the development of cystic encephalomalacia in perinatal CHIKV infection needs further investigation.…”

“…21 Some data suggest that preterm neonates are at higher risk of severe cystic leukoencephalomalacia in parechovirus infection. 21 Whether prematurity is also a risk factor for the development of cystic encephalomalacia in perinatal CHIKV infection needs further investigation. In the chronic phase, differential diagnoses for cystic lesions include herpes simplex infection and hypoxic-ischemic encephalopathy.…”

Longitudinal brain magnetic resonance imaging of children with perinatal Chikungunya encephalitis

“…Other diseases can also cause lesions similar to those observed in patients with vertically transmitted CHIKV infection, such as hypoxic-ischaemic encephalopathy, and neonatal infection by herpes simplex virus, parechovirus, enterovirus and rotavirus. 10 Necrosis secondary to hypoxic-ischaemic injury results in loss of periventricular white matter, passive ventriculomegaly with irregular margins and thinning of the corpus callosum. Cavitations represent end-stage disease.…”

“…In addition, it should be noted that distinguishing CHIKV perinatal infection from enterovirus, rotavirus and neonatal herpes simplex encephalitis by imaging studies alone may be impossible. 10 Therefore, perinatal infection with CHIKV should be considered in the differential diagnosis of neonatal sepsis, when the mother was symptomatic in the peripartum period. Despite this, the MRI aspect of brain lesions secondary to mother-to-child CHIKV transmission is different from other congenital infections, such as cytomegalovirus, Zika, rubella and toxoplasmosis, which can cause microcephaly, cerebral calcifications and malformations of cortical development, which are not seen in CHIKV infection.…”