Early recognition of thiamine deficiency: ocular motor deficits in a patient with nutritional deprivation due to persistent antibiotic-related nausea.

A 73-year-old male presented with new onset dizziness and a 22-kg weight loss due to antibiotic-induced nausea/vomiting. Due to gaze-evoked nystagmus (GEN), thiamine deficiency was suspected. Within 12 h after replacement, his GEN decreased.In patients with nutritional deprivation, new onset GEN should prompt further diagnostics and immediate thiamine supplementation to avoid disease progression.