Mild encephalitis/encephalopathy with a reversible splenial lesion associated with respiratory syncytial virus infection in infants.

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinicoradiologic syndrome typically characterized by transient mild encephalitis or encephalopathy with reversible lesions being found in the splenium of corpus callosum (SCC) by magnetic resonance imaging (MRI). A variety of pathogens including influenza virus, rotavirus, and adenovirus associated with MERS have been reported. However, respiratory syncytial virus (RSV)-related MERS is relatively rare in infants. In this study, we report two Chinese infants who suffered from RSV-related MERS. Both infants manifested as fever, seizure, and altered states of consciousness with confirmed detections of RSV-RNA in the specimens from throat swab. Clinical symptoms/signs such as apnea and shallow breathing were also noted in these two infants. Furthermore, brain MRI images indicated reversible isolated lesions with transiently reduced diffusion in the SCC. Fortunately, both of these two infants recovered completely following treatment within a month. Our study suggests that RSV may serve as a novel causative agent for MERS in infants. Clinicians should focus more attention on RSV-related MERS in infants in order to improve early accurate diagnosis and therapeutic decision making.