Acute Bilateral Visual Loss as an Atypical Manifestation of Wernicke Encephalopathy Secondary to Hyperemesis Gravidarum: A Case Report and Narrative Literature Review.

Wernicke encephalopathy (WE) is a severe neurological condition caused by thiamine deficiency that remains underreported in pregnancy. We report a clinical diagnosis of WE in a 41-year-old woman, gravida 2, para 1, at 16 weeks of gestation. She presented with acute, painless visual impairment, severe dietary restriction, and marked weight loss secondary to severe hyperemesis gravidarum (HG). Examination revealed reduced visual acuity, horizontal nystagmus, psychomotor retardation, and an ataxic gait. The initial diagnosis was delayed due to her atypical presentation and the absence of MRI or blood thiamine level confirmation. However, empirical treatment with IV thiamine was followed by rapid visual and cognitive recovery within 24 hours. The pregnancy was subsequently complicated by fetal growth restriction and preterm delivery. This case illustrates the necessity of empirical treatment for WE based on clinical criteria in pregnant patients with HG. Recognizing atypical presentations and administering thiamine promptly are critical because delayed treatment may result in irreversible maternal neurological complications and adverse pregnancy outcomes.