A 58-YEAR-OLD woman was admitted with a 6-week history of increasing sensory disturbances of her lower legs and a gradual gait disturbance. She denied experiencing muscle weakness, but walking in the dark was nearly impossible because of difficulty coordinating her gait without optical control. During the previous few years, she had had recurrent problems with gastritis. On neurological examination, a sensory cross-section was found at T4, vibration sense was absent in both legs, and the position sense in her feet was severely impaired. The patient denied any bladder disturbances. There was mild paresis in the musculature of the lower extremity limb girdle. Reflexes were absent in both lower legs, and pyramidal signs were present on her left side. Results of routine hematologic and biochemical blood tests showed megaloblastic anemia (mean corpuscular volume, 120 fL; hemoglobin, 10.5 g/dL; and hematocrit, 33.1%). Serum vitamin B12 was reduced to 160 pg/mL, and the Schilling test revealed a severely impaired resorption of vitamin B12. A gastroscopy indicated atrophic gastritis. T2-weighted images on initial magnetic resonance imaging (MRI) scans showed an impressive hyperintensity of the dorsal column fibers throughout the spinal cord (Figure 1A-D), reflecting severe demyelination and swelling, mainly of the heavily myelinated nerve fibers.1 The patient immediately received cyanocobalamin substitution therapy. Subsequently, a slow but continous neurological remission was observed. After 3 months, deep tendon reflexes of the lower extremities were again apparent, and the pyramidal signs had disappeared. There was only a mild residual sensory cross-section at T12. After a course of therapy with 2 mg of cyanocobalamin twice a week for 9 months, vibration and position sense had normalized, and afferent ataxia had completely disappeared. Only a mild residual dysaesthesia of both thighs was reported. Normalization of laboratory abnormalities and MRI findings (Figure 2A-D) paralleled the clinical improvement.
Wiendl H, Strayle-Batra M, Schulz JB. Very Bright Dorsal Columns: Spinal Magnetic Resonance Imaging in Funicular Myelosis. Arch Neurol. 2002;59(1):147–148. doi:10.1001/archneur.59.1.147
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