[Wernicke encephalopathy : a neuro-ophthalmological side effect of bariatric surgery].

Due to an increase in the worldwide prevalence of obesity and the efficiency of bariatric surgery, this procedure is more often performed. Besides its benefits, it has also disadvantages and may be the cause of nutritional deficiencies. Thiamin deficiency is particularly important to diagnose and to treat early as it can lead to major sequelae and even to death. Wernicke's encephalopathy is the most frequent presentation associating confusion, ataxia, ophtalmoplegia and nystagmus. The full triad is not usually observed, which may lead to sub-diagnosis of this affection. The diagnosis is clinical, biological and radiologic thanks to the brain MRI. Intravenous thiamin supplementation therapy must be administered as fast as possible in order to avoid long-term damages. In the ophthalmological field, the potential sequelae are ophthalmoplegia, nystagmus and optic neuropathy. Therapeutics for nystagmus are pharmacological, surgical and/or optical. We illustrate this condition with a case report of an 18-year-old man developing Wernicke's encephalopathy as early as six weeks after a sleeve gastrectomy.