Background: Thyrotoxic periodic paralysis (TPP) is a potentially life-threatening complication of thyrotoxicosis, characterized by hypokalemia and muscle paralysis. Objective: TPP, although becoming more prevalent in western countries, is still often not recognized due to lack of familiarity and the subtlety of the thyrotoxic symptoms. Early recognition by emergency physicians can prevent potential mortality. Case Report: A 23-year-old Vietnamese male presented with a 2-h history of complete flaccid quadriplegia and chest tightness. Electrolyte studies revealed a critical potassium level of 1.4 mmol/L. The patient was admitted to the intensive care unit where further workup revealed thyrotoxicosis and the patient was subsequently diagnosed with TPP. Conclusions: TPP should always be considered as a differential in patients, especially in young males of Asian descent with lower-limb paralysis or weakness. We present this case, followed by a review of the literature. (C) 2014 Elsevier Inc.