Neuropathy by folic acid supplementation in a patient with anaemia and an untreated cobalamin deficiency: a case report.

The rising rates of bariatric surgery (BS) are accompanied by neurological complications related to nutrient deficiencies. One of the risk factors for neurological complications in BS patients is poor vitamin and mineral supplementation. Prevention, diagnosis and treatment of these disorders are necessary parts of lifelong care after BS. Particularly important for optimal functioning of the nervous system are vitamin B1 , B6 , B12 (cobalamin), E, copper and possibly vitamin B11 (folic acid). In this case report, we narrate about a patient with anaemia and multiple vitamin and mineral deficiencies after Roux-en-Y gastric bypass (RYGB) with an alimentary limb of 150 cm and a biliopancreatic limb of 100 cm. RYGB is associated with an increased risk of vitamin deficiencies, especially a vitamin B12 deficiency. The patient in this case report developed psychiatric-neurological symptoms due to folic acid supplementation in an untreated cobalamin deficiency. Second, we tried to elucidate the vitamin physiology to understand specific mechanisms after BS.