Subacute combined degeneration of the spinal cord despite prophylactic vitamin B12 treatment

Abstract

We describe a 35 year-old man presenting with a four-week history of non-painful limb paraesthesias and unsteady gait causing falls. On examination he had an ataxic gait associated with dorsal column sensory loss. He had a medical history of a partial gastrectomy six years prior and anaemia. He had received monthly intramuscular hydroxycobalamin injections since the gastrectomy. Laboratory tests revealed normal vitamin B12 and holotranscobalamin levels, a reduced serum caeruloplasmin of 0.05 g/L (normal: 0.22–0.58 g/L), a copper-to-caeruloplasmin ratio of 1.9 μmol/L (11.0–22.0 μmol/L) and a reduced 24-hour urinary copper concentration of <0.30 μmol/L (0–0.3 μmol/L). Cerebrospinal fluid analysis, nerve conduction studies, electromyography and visual-evoked responses were unremarkable. MRI revealed abnormal hyperintense signal in the cervical dorsal columns. Hypocupric myelopathy was diagnosed and he was treated with daily oral elemental copper. Three months later, his walking and balance had improved although there was no change noted on MRI.