[Involvement of the peripheral and pyramidal nervous system in Crohn disease. Determining role of folic acid deficiency].

We report on the case of a 16-year-old male patient who presented with a peripheral neuropathy remarkable by the severity of pain, the proximal involvement and the association with an underlying myelopathy. All these symptoms coincided with an acute exacerbation of Crohn disease (regional enteritis) involving mainly the duodenojejunal segment, and were ascribed to a major folic acid deficiency, with total recovery following supplementation. In this connection we recall the various neurological symptoms induced by folic acid deficiency. We point out how difficult it is to prove the responsibility of such deficiencies in the production of neurologic diseases, mainly because of the possible intrication with other pathogenic factors: combined deficiencies or direct action of the factor responsible for the deficiency on the nervous system. Guidelines for solving these difficulties are suggested.