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.