特異的なMRI所見にて診断し得た亜急性連合性脊髄変性症の1例――22例のMRI所見のレビュー―

A Case of Subacute Combined Degeneration of the Spinal Cord Diagnosed by Characteristic Findings of Magnetic Resonance Imaging : Case Report and Review of 22 Cases

Ⅰ．はじめに

　Vitamin B₁₂（VB_12）欠乏時に生じる亜急性連合性脊髄変性症は稀な疾患だが，MRIの普及以来，報告例が増加している．一般的に亜急性連合性脊髄変性症は後索症状を中心とする症状を呈するが，症状完成前にMRIにて早期診断の可能性がある．われわれは両手指のしびれ感のみで発症したが，血液生化学的検査および頸髄MRIにて亜急性連合性脊髄変性症と診断し，VB₁₂投与により軽快した症例を経験したので報告する．

Subacute combined degeneration (SCD) is a rare cause of demyelination of the dorsal and lateral columns of the spinal cord,and is a neurogenic complication due to vitamin B12 deficiency. This report concerns a patient with progressive sensory disturbance,but no abnormal neurological findings. A 73-year-old man with gastrectomy presented with a 6-month history of gradually worsening tingling in both hands. Magnetic resonance imaging (MRI) of the cervical spine clearly showed symmetrical high-signal areas on T2WI involving the posterior columns of the cervical cord from C2 through C6. A diagnosis of SCD of the spinal cord was considered and confirmed by laboratory findings. The patient was treated with vitamin B12 supplements and showed gradual improvement in his clinical symptoms. Repeat MRI of the cervical spine after 3 months indicated a slight decrease in the area of the abnormal signal. Among all the possible causes of myelopathy,SCD of the spinal cord,involving neurological complications due to vitamin B12 deficiency,is one of the less often encountered diseases. Nevertheless,SCD should be considered in the differential diagnosis of all spinal cord,peripheral nerve,and neuropsychiatric disorders.