Rinsho Shinkeigaku (Clinical Neurology)

Case Report

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) with a family history: an adult case

Fumiya Kutsuna, M.D.1), Miki Ueno, M.D.1)2), Masahiro Tokuda, M.D.1), Hiroshi Iwanaga, M.D., Ph.D.1) and Keisuke Tsutsumi, M.D., Ph.D.3)

1) Department of Neurology, National Hospital Organization Nagasaki Medical Center
2) Present address: Department of Internal Medicine, Terasawa Hospital
3) Department of Neurosurgery, National Hospital Organization Nagasaki Medical Center

We present an adult case of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). A 26-year-old man with a family history of MERS presented to our hospital owing to dysarthria and dysesthesia of the right side of his body. The duration of these symptoms was approximately 4 hours. T2 and diffusion weighted MRI showed high signal intensity lesions in the bilateral deep white matter. On a 3-week follow-up MRI, the lesions had completely disappeared. We attributed this clinical course and image findings to MERS. The patient had experienced similar symptoms at the age of 8 years old. Furthermore, his younger brother showed a similar clinical history and experienced a few recurrence events during the age of 9-16 years old. The mechanism of MERS remains controversial. However, similar to our case, there are some case reports with a family history. In addition, a previous report has confirmed the existence of a heterozygous variant in the myelin regulatory factor gene in patients with MERS. Some genetic factors may induce MERS, especially with extensive white matter lesions.
Full Text of this Article in Japanese PDF (1718K)

(CLINICA NEUROL, 62: 224−230, 2022)
key words: deep white matter lesion, mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), familial, transient ischemic attack, type 2 lesion

(Received: 7-Sep-21)