Marchiafava-Bignami病を併発した双極Ⅰ型障害の1例

A Case of Bipolar Ⅰ Disorder Complicated with Marchiafava-Bignami Disease

抄録

　Marchiafava-Bignami病(MBD)は脳梁に脱髄壊死を生ずる脳器質疾患で，アルコール依存に伴うビタミンB₁欠乏に起因するとされる。在宅生活を送っていた双極Ⅰ型障害の男性症例が，MBDを併発したので報告する。本例では発症3日目のMRIで脳梁膨大部と左側被殻に高信号域を認めた。臨床症状としては意識障害，嚥下障害，構音障害，筋緊張亢進，振戦，原始反射，左手の肢位異常などを認めたが，脳梁離断症候ははっきりしなかった。ただちに開始されたビタミンB群補充療法により比較的順調に回復し，発症83日目のMRIでは脳梁膨大部の高信号域は消失し，左側被殻のそれは軽減していた。退院促進と地域支援の流れの中で，在宅の精神障害者に原疾患と異なる精神神経症状がみられた場合，MBDの可能性も考え早期にMRI検査を行う必要がある。

　Marchiafava-Bignami disease (MBD) is a relatively rare organic brain disease associated with thiamine deficiency resulted from chronic alcohol intake;it is characterized by demyelination and necrosis of the corpus callosum. Here, we present the case of a 47-year-old male outpatient with bipolar Ⅰ disorder complicated with MBD. Three days after the onset of MBD, diffusion-weighted MRI images of his brain showed high signal-intensity lesions in the central portion of the splenium of the corpus callosum and the left putamen. On admission, his signs and symptoms were a disturbance of consciousness, difficulty swallowing, impaired walking, dysarthria, muscle rigidity, tremor, primitive reflexes, and abnormal posture of his left hand but not disconnection syndrome. Using rapid parenteral vitamin B supplementation, he recovered relatively quickly. A follow-up MRI study on day 83 showed no lesions in the splenium but slight ones in the left putamen. Brain MRIs should be performed as early as possible in psychiatric outpatients. Especially those who show variable neuropsychiatric symptoms different from their original psychiatric disorder, and those with chronic alcohol intake and malnutrition. This will aid in ruling out organic brain diseases such as MBD.