Sudden vision loss in pregnancy: Wernicke's encephalopathy in a patient with hyperemesis gravidarum.

Wernicke's encephalopathy, the acute phase of Wernicke-Korsakoff syndrome, is characterised as a triad of altered mental status, ocular signs and ataxia. Our patient presented with hyperemesis gravidarum, which is a rare aetiology of Wernicke's encephalopathy. The patient did not have any oculomotor abnormalities, which are more common and classically described in Wernicke's triad. The sudden visual loss in both eyes can be attributed to acute optic neuropathy. Our case highlights a unique ophthalmic presentation with retinal haemorrhages and optic disc oedema as unusual manifestations of Wernicke's encephalopathy. The dramatic and complete reversal of visual symptoms within 48 hours after starting parenteral thiamine retrospectively supports the diagnosis.