Slowly progressive folate-deficiency myelopathy: Report of a case

Background Folate deficiency is known to be associated with subacute combined degeneration of the spinal cord; however, reports of long-standing cases are rare. Although neurological deficits due to folate deficiency have been reported to respond to folic acid supplementation, the functional outcomes have not been fully elucidated. Objective The aim of the study was to evaluate the clinical features and response to folate supplementation in a patient with folate deficiency manifested over 10 years as a slowly progressive myelopathy. Methods We performed comprehensive clinical screening, electrophysiological testing, and posturography before and after folate supplementation. Results A 49-year-old man had a slowly progressive gait disturbance for 10 years. He had not eaten fresh green vegetables for more than 10 years. Neurological examination revealed spastic paraplegia and absence of any vibration sense in the lower limbs accompanied by a positive Romberg's sign. Serum folate level was low, and plasma homocysteine level was elevated. Levels of blood thiamine and serum cobalamin were normal. We diagnosed the patient with myelopathy due to folate deficiency. Folic acid supplementation led to improvement of his symptoms; posturography and walking speed tests showed partial improvement, while the somatosensory-evoked potentials and central motor conduction time remained unchanged. Conclusions Folate deficiency should be considered as a differential diagnosis of chronic slowly progressive myelopathy. The present case suggests the importance of early diagnosis and treatment before the adverse neurological manifestations of folate deficiency become irreversible.