Nonalcoholic Wernicke Encephalopathy Following Prolonged Intermittent Fasting: A Case Report

Wernicke encephalopathy (WE) is an acute and potentially reversible neurological disorder caused by thiamine deficiency and is most commonly associated with chronic alcohol use. However, it can also occur in nonalcoholic individuals with nutritional deprivation, where diagnosis is often delayed because of low clinical suspicion. We report a case of WE occurring in the setting of prolonged intermittent fasting for weight loss. The patient presented with subacute neurological symptoms, including gait disturbance, visual complaints, and cognitive impairment. Neurological examination revealed findings consistent with encephalopathy, including ocular motor abnormalities and ataxia. Routine laboratory investigations were largely unremarkable, aside from evidence of nutritional deficiency. Initial neuroimaging did not reveal acute abnormalities, while subsequent magnetic resonance imaging (MRI) demonstrated changes compatible with WE. A detailed dietary history identified prolonged fasting with inadequate nutritional intake as the likely contributing factor. The patient was treated with parenteral thiamine and supportive nutritional management, resulting in clinical improvement. This case emphasizes the importance of recognizing nonalcoholic causes of WE in the context of restrictive dietary practices. Early recognition and prompt thiamine replacement are essential to prevent long-term neurological complications, underscoring the need for increased clinical awareness as fasting-based dietary approaches become more common.