Neonatal Rotavirus-Associated Leukoencephalopathy Is One of the Main Causes of Fifth-Day Fits.

Our province recently experienced an outbreak of neonatal rotavirus-associated leukoencephalopathy. This study aimed to verify whether rotavirus-associated leukoencephalopathy constituted fifth-day fits, which prevailed in Europe and Australia between the 1970s and mid-1980s. Of 118 full-term neonates who were admitted between 2008 and 2017 due to seizures, those who fulfilled the following criteria for fifth-day fits were included: healthy full-term neonates prior to seizures; absence of perinatal asphyxia; seizure onset during 4-6 days of age; and no known cause of neonatal seizures. Overall, 54 patients (45.8%) met the criteria for fifth-day fits. Of them, 44 patients (81.5%) also had rotavirus-associated leukoencephalopathy. The mean annual incidence of fifth-day fits was 5.4 cases, which peaked in 2012-2013 (13 cases) and became zero in 2017. Fifth-day fits with rotavirus-associated leukoencephalopathy accounted for 37.2% of neonatal seizures, which peaked at 70.6% in 2012, and gradually reduced to zero in 2017. Concordance of clinical features between rotavirus-associated leukoencephalopathy and fifth-day fits and their epidemic-like features suggest that rotavirus-associated leukoencephalopathy is one of the main causes of fifth-day fits.