Sub-acute combined degeneration with an initially normal level of vitamin B12: a case report

INTRODUCTION: The neurological manifestation of vitamin B12 deficiency can occur as a result of peripheral nerve pathology or lateral and posterior column involvement, also known as "sub-acute combined degeneration". This case report demonstrates an unusual presentation of SCD with normal B12 level. CASE PRESENTATION: A 39-year-old man was referred to the outpatient neurology clinic with a two month history of distal upper extremities numbness and fine motor movement difficulties. Initial vitamin B12 level was normal. A repeat MR imaging of the cervical and thoracic spine showed extensive posterior cervical cord flame-shaped lesions. His repeat vitamin B12 level was 41 pg/ml (normal; 200 ph/ml). He received monthly injections of vitamin B12. After six months his symptoms were resolved and his repeat spinal MRI showed resolution of the previous lesions. CONCLUSION: We recommend that every patient presenting with numbness and lesions on a spinal MR imaging should have their vitamin B12 level checked.