To the Editor.—
We wish to report two cases of cobalamin deficiency that produced neurologic deficit in patients with normal hematocrit levels, mean RBC volume, and serum cobalamin levels by radiodilution assay.
Report of Cases.—
Case 1.—The condition of a 50-year-old woman was evaluated because of a three-month history of burning dysesthesias in the arms and legs, and ataxic gait. Two years earlier, the patient had had 45 cm of terminal ileum resected because of ischemic necrosis. Subsequently, she had chronic diarrhea. The neurologic examination showed marked loss of proprioceptive and vibratory sensation in the distal lower extremities, ataxic gait, and hyperactive reflexes with Babinski's signs. The patient had a normal myelogram and normal CSF analysis results, including an unremarkable oligoclonal banding pattern. The serum cobalamin level by radiodilution assay was 334 pg/mL (normal, 300 to 1,000 pg/mL); however, the cobalamin level by microbiologic assay was 113 pg/mL (normal, 130
Ruff RL, Scally J. Reversible Neurological Deficits in Patients With Normal Serum Vitamin B12 Levels. Arch Neurol. 1980;37(4):255. doi:10.1001/archneur.1980.00500530093029