A patient with Marchiafava-Bignami disease type A transported by ambulance with impaired consciousness and malnutrition was successfully treated after early diagnosis by MRI.

Marchiafava-Bignami disease (MBD) is a very rare disorder characterized by demyelination and necrosis of the corpus callosum. A 53-year-old male was transported to the emergency room with impaired consciousness. On his arrival, he was quite emaciated. CT examination revealed no hemorrhagic lesions whereas MR images showed hyperintense areas throughout the corpus callosum, leading to a diagnosis of MBD. His impaired consciousness improved with treatment, including parenteral thiamine administration. When examining patients with impaired consciousness because of malnutrition, MBD should be taken in consideration and the incorporation of head MR imaging into the examination protocol enables early diagnosis and treatment, and may improve the prognosis.