痴呆を伴う筋萎縮性側索硬化症（ALS-D）の長期経過症例

A Case of Amyotrophic Lateral Sclerosis with Dementia Presenting Long Clinical Course

要旨　痴呆を伴う筋萎縮性側索硬化症（ALS-D）の1例を報告した。本例は当初Pick病と診断されていたが，発症約7年後より運動症状を呈し，全経過約8年で死亡した。本例の特徴は精神症状と運動症状の発現が約7年離れており，全経過約8年と長期の経過を示した点である。ALS-Dでは精神症状と運動症状は発症後1～2年以内に共存するとされているが，本例同様の経過を示す症例が少数ながら報告されている。発病当初Pick病と診断された症例が，数年の経過を経てALS-Dと診断される場合があることを指摘した。また近年注目されている前頭側頭葉変性症（FTLD）における本例の位置づけ，ALS-Dとの関係についても考察した。

　We describe a patient with amyotrophic lateral sclerosis with dementia（ALS-D） displaying a long clinical course. A 68-year-old Japanese male with no family history of note was admitted complaining of severe dysarthria and dysphagia. At 63 years old, Pick's disease was diagnosed on the basis of abnormal behavior, such as “Denkfaulheit" and moria, and temporal lobe atrophy observed on magnetic resonance imaging（MRI）. Five years after onset, dysarthria and dysphagia emerged, and gradually worsened. On admission, muscular weakness of the upper extremities, fasciculation, and exaggerated tendon stretch reflexes were noted. Needle electromyography performed on the left upper and lower extremities revealed neurogenic pattern changes. Based on these findings and clinical course, ALS-D was diagnosed. Due to severe bulbar palsy, verbal communication was impossible. However, neither specific symptoms of dementia nor abnormal behavior was demonstrated, although this latter had been observed 5 years ago, with only short-term memory impairment apparent. MRI disclosed severe knife-edge atrophy of bilateral temporal lobes, most prominently in the anterior regions. SPECT images revealed decreased uptake of tracer in bilateral inferior temporal lobes, predominantly on the left side. The patient died suddenly 4 months after admission, and post-mortem examination was not conducted. Total clinical course was about 8 years.

　Several cases of ALS-D have displayed similar clinical courses to the presented case. Some of these would also have initially been diagnosed as Pick's disease. We speculate that cases displaying psychiatric symptoms for several years and initially diagnosed as Pick's disease may finally be diagnosed as ALS-D upon the eventual emergence of motor symptoms（bulbar palsy）.