Thiamine Deficiency Secondary to Anorexia Nervosa: An Uncommon Cause of Peripheral Neuropathy and Wernicke Encephalopathy in Adolescence

IntroductionWe present a developmentally appropriate adolescent boy who presented with upper and lower extremity glove-and-stocking paresthesias, distal weakness, vertigo, high-pitched voice, inattention, ataxia, and binocular diplopia after a voluntary 59-kg weight loss over 5 months.Clinical InvestigationsExtensive investigations revealed serum thiamine levels <2 nmol/L. Brain magnetic resonance imaging revealed symmetric abnormal T2 prolongation of the mammillary bodies. Nerve conduction studies were consistent with axonal, length-dependent polyneuropathy. Together, these findings were diagnostic for peripheral polyneuropathy and Wernicke encephalopathy secondary to thiamine deficiency.ConclusionThis patient illustrates that eating disorders can be an uncommon cause of rapidly progressive paresthesias, weakness, and neurological decline due to thiamine deficiency.