RESUMO
Beriberi neuropathy (thiamine deficiency) and Guillian-Barre Syndrome (GBS) both can present with areflexia and progressive ascending weakness. A physical examination can be equivocal between the two. In cases where GBS is suspected clinically but initial work-up with cerebral spinal fluid (CSF) studies and magnetic resonance imaging (MRI) of the spine are not diagnostic, nerve conduction study/electromyography (NCS/EMG) should be done to evaluate beriberi neuropathy. Presumptive treatment should be started while awaiting confirmation from nutritional laboratory investigations. Here we present a rare case of a GBS mimic involving a 17-year-old patient with food restriction that led to thiamine deficiency causing beriberi neuropathy and Wernicke encephalopathy.