Thiamine deficiency after bariatric surgery may lead to Wernicke encephalopathy.

Of special note are neurological complications, which manifest at 3 to 20 months after bariatric surgery and all affect patients experiencing prolonged vomiting. The neurological symptoms include chronic and subacute peripheral neuropathy, acute peripheral neuropathy, burning feet, meralgia paresthetica, myotonic syndrome, posterolateral myelopathy, and Wernicke encephalopathy [1]. Since the number of bariatric surgeries is dramatically expanding and the attention to neurological symptoms increasing, more cases of WE1 are reported, though their percentage in the post-surgery population is decreasing. For example, in the United States 8 cases were reported out of 100,000 surgeries in 2002 and 9 cases were published in 2006–2007 among approximately 400,000 surgeries. In southern Europe a combined total of 6 WE cases among 3241 patients undergoing biliopancreatic diversion were reported. A systematic review of the literature [2] was published in 2008. The report [2] describes 84 cases of WE between 1991 and 2008. Gastric bypass or a restrictive procedure had been performed in 80 cases (95%). Admission to hospital for WE occurred within 6 months of surgery in 79 cases (94%). Frequent vomiting was a risk factor in 76 cases (90%) and had lasted for a median of 21 days before admission. Intravenous glucose administration without thiamine was a risk factor in 15 cases (18%). Brain magnetic resonance imaging identified lesions characteristic of WE in 14 of 30 cases (47%).