Clinical and imaging findings of 11 patients with mild encephalitis/encephalopathy with a reversible splenial lesion

Abstract

Objective To investigate the clinical and imaging features of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). Methods The clinical and imaging data of 11 patients diagnosed with MERS were retrospectively analyzed, including 4 adults and 7 adolescents and children. The clinical and imaging features of these patients were summarized. Results Eleven MERS patients had a history of precursor infection. Encephalopathy symptoms included headache and drowsy in 6 cases, disturbance of consciousness in 3, epilepsy in 2, illusion in 2 and delirium in 1. The symptoms of all the MERS patients obviously alleviated in 2 weeks. MRI showed all cases as isolation of splenium of corpus callosum lesions, including 9 cases of circular abnormal signals in central of splenium of corpus callosum and 2 cases of arc-shaped abnormal signals in splenium of corpus callosum. The abnormal signal showed high-signal on T2-weighted and diffusion-weighted with low-signal on apparent diffusion coefficient images in the splenium of corpus callosum. After the onset of 4 weeks, MRI returned to normal, and the corpus callosum of abnormal signal lesions disappeared. Conclusions Most patients have a history of precursor infection before the onset of the MERS. The clinical manifestations of MERS patients include encephalopathy symptoms such as headache, disturbance of consciousness, seizures, illusion, etc. MRI shows circular or arc-shaped lesions in splenium of corpus callosum, which demonstrate high-signal on diffusion-weighted and low-signal on apparent diffusion coefficient images. Prognosis of MERS patients is mostly good. Some patients' lesions on MRI appear later than the onset of encephalopathy symptoms. Key words: Encephalitis; Consciousness disorders; Epilepsy; Corpus callosum; Magnetic resonance imaging