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Images in Neurology |

Vitamin B12 Deficiency

Ken Nakamura, MD, PhD; Pratik Mukherjee, MD, PhD; Raymond A. Swanson, MD
Arch Neurol. 2004;61(6):960. doi:10.1001/archneur.61.6.960.
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A 50-year-old man was initially seen with a 2-month history of bilateral lower extremity paresthesias and electric shock–like sensations with neck flexion (Lhermitte sign). He had maintained a strict vegetarian (vegan) diet for more than 15 years. Examination revealed markedly impaired lower extremity vibratory and joint-position sensation, with relative preservation of pain and temperature. Strength and reflexes were normal. The serum vitamin B12 level was less than 50 pg/mL (37 pmol/L) (reference range, 211-911 pg/mL [156-672 pmol/L]). Test results for antiparietal cell and anti-intrinsic factor antibodies were negative. Three months after the initiation of intramuscular repletion, the patient's vitamin B12 level had normalized and his symptoms had partially resolved.

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T2-weighted magnetic resonance imaging of the thoracic spine revealed abnormal T2 prolongation in the bilateral dorsal columns (arrows) extending from the level of T3 to T11. A, A sagittal section of T2-T4. B, An axial section at T7.

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