Abstract
Subacute combined degeneration (SCD) is a rare neurological complication of vitamin B12 deficiency, characterized by demyelination of the dorsal and lateral spinal cord. Herein, we describe three cases, who presented with SCD, one related to reduced intake of vitamin B12 because of a vegetarian diet and two related to nitrous oxide exposure during surgery. MR images of our patients revealed symmetrical hyperintense signals in dorsal and lateral columns in T2 weighted series. After treatment with intramuscular B12 injections (1 mg daily for 2 weeks, once weekly thereafter for three months) all patients showed improvement of their symptoms. Abnormalities of the spinal cord on MRI resolved in three months. In conclusion, SCD either due to nitrous oxide exposure or due to reduced intake of vitamin B12 is a reversible condition, when detected and treated early.
Highlights
Vitamin B12 deficiency causes a wide range of hematological, gastrointestinal, and neuropsychiatric disorders [1]
Anemia is a common early manifestation pointing to an underlying vitamin B12 deficiency, neurological symptoms may occur in the absence of hematological abnormalities [2]
In the gastrectomized rat model, vitamin B12 deficiency leads to increased spinal cord synthesis and increased cerebrospinal fluid (CSF) levels of two myelinotoxic cytokines, tumor necrosis factor-alpha (TNF-α) and soluble (s) CD40:sCD40 ligand dyad, and a myelinotoxic growth factor, nerve growth factor (NGF)
Summary
Vitamin B12 deficiency causes a wide range of hematological, gastrointestinal, and neuropsychiatric disorders [1]. The most frequent causes of vitamin B12 deficiency are malabsorption (e.g., pernicious anaemia, gastrectomy, intestinal infections, tropical sprue, terminal ileal conditions including Crohn’s disease, and resection), pancreatic exocrine insufficiency, medications (colchicine, neomycin, and p-aminosalicylic acid), disorders of intracellular cobalamin metabolism (methylmalonic aciduria and homocystinuria), increased requirement (in hyperthyroidism and alpha thalassemia), and inadequate intake with food (e.g., vegetarianism and veganism) [1,2,3]. Nitrous oxide exposure during surgical procedures or recreational use is a rare cause of acute vitamin B12 inactivation [4,5,6]. The spinal cord lesion caused by vitamin B12 deficiency is known as subacute combined degeneration (SCD). We describe three patients, who presented with SCD, one related to reduced intake of vitamin B12 because of a vegetarian diet and two related to nitrous oxide exposure during surgery, with improvement both clinical and radiological after vitamin B12 replacement
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