Lhermitte's Sign in Cobalamin (Vitamin B12) Deficiency

LHERMITTE'S sign (electric shock-like dysesthesia produced by neck flexion) was first described by Marie and Chatelin in 1917.1In 1924, Lhermitte et al described in detail a patient with multiple sclerosis and electric dysesthesias.2Since then, Lhermitte's sign has been described in association with tumors of the cervical cord, arachnoiditis, cervical spondylitis, radiation myelitis, subacute combined degeneration of the cord, and nitrous oxide exposure.3-5Recently, we have seen two patients with Lhermitte's sign who were found to have cobalamin (vitamin B12) deficiency. Report of Cases Case 1.— A 38-year-old woman complained of fatigue and electric dysesthesia with neck flexion for several months prior to evaluation. Examination revealed a mild decrease in vibration and position sense in the extremities. Initial laboratory data included a hemoglobin level of 9.3 g/dL, a leukocyte count of 2.6×109/L, and a platelet count of 330 ×109/L. The blood