Wernicke encephalopathy due to hyperemesis gravidarum in pregnancy

Wernicke’s encephalopathy is a life-threatening acute or sub-acute neurological emergency characterized by a triad of ataxia, confusion, ophthalmoplegia caused by thiamine deficiency, mostly observed in chronic alcohol users. Wernicke's encephalopathy due to causes other than alcohol abuse is uncommon and often misdiagnosed.  In pregnancy, it is an unknown pathology, with poor prognosis, which occurs secondarily to hyperemesis gravidarum. We present a rare case of a 30-year-old female with mild learning disability, at 15 weeks of gestational age, with a history of previous hospital admission for severe vomiting and referred to Maternal Mental Health Clinic for abnormal behaviour. She had classic symptoms of Wernicke’s Encephalopathy on presentation, and was immediately treated with thiamine. Her symptoms improved in a few days.