(849) Pediatric Wernicke Encephalopathy Presenting With Syndrome of Inappropriate Antidiuretic Hormone

Introduction: Wernicke’s encephalopathy is a well described neurologic complication of thiamine deficiency that is classically characterized by a triad of mental confusion, ophthalmoplegia, and gait ataxia. Although commonly linked to alcoholism and thiamine deficiency in adults, it can present in a number of clinical contexts in pediatric patients.

Description: A developmentally delayed 21-month-old male with restrictive dietary habits presented with weight loss, poor appetite, hypoglycemia, and metabolic acidosis. Shortly after his admission, he exhibited staring episodes, changes in muscular tone, and non- purposeful extremity movements. Although clinically euvolemic, he was found to have hyponatremia to 120 mmol/L with elevated urine osmolality. Additionally, he had brain MRI findings consistent with Wernicke’s encephalopathy including abnormal patchy T2/FLAIR hyperintensity along the dorsomedial thalami, mammillary bodies, periaqueductal gray matter, dorsal medulla, and cerebellar vermis. His differential diagnosis included seizures, inborn errors of metabolism, and demyelinating diseases, which were all subsequently ruled out. His mental status improved with thiamine administration and his hyponatremia resolved with fluid restriction.

Discussion: This case highlights the importance of a broad differential for altered mental status in critically ill pediatric patients. The incidence of Wernicke’s encephalopathy in the pediatric population is not well known and the classic triad at presentation is rare. Diagnosis via 2 of 4 Caine criteria (dietary deficiency, oculomotor abnormalities, cerebellar dysfunction, and either altered mental status or impaired memory) as opposed to the classic triad can increase sensitivity for diagnosis. Our patient’s course was complicated by SIADH, diagnosed by hyponatremia, hypoosmolality, urine osmolality above 100 mOsmol/kg H2O, and clinical euvolemia. It is well established that central nervous system disturbances such as traumatic brain injury can lead to SIADH, however WE presenting with SIADH is much less common, and perhaps under-appreciated. In conclusion, increasing awareness among pediatric providers about the possibility of WE and its unique presentations is vital as the prognosis depends on the timing of diagnosis and thiamine supplementation.