Introduction: Many internal medicine conditions may be presented to pain centers and an interdisciplinary and holistic approach is necessary for optimal management. Case Description: A 46 year old man presented to the interdisciplinary pain clinic at Shefa Neuroscience Research Center complaining of periodic weakness, pain and tenderness in proximal lower extremities, anxiety, irritability and weight loss since 3 months ago. On examination and laboratory results, hyperthyroidism and severe hypokalemia were evident. On echocardiography, ejection fraction was 25%. He was admitted in coronary care unit for cardiac monitoring and received propranolol and methimazole. Results: After stabilizing the heart rate and correction of potassium level, paralysis was completely subsided and ejection fraction increased to 55%. He was discharged from the hospital in good situation. Conclusion: Hyperthyroid hypokalemic periodic paralysis is a rare but well-known condition with episodes of muscular weakness or paralysis. It can be diagnosed by good history taking, physical examination, and laboratory evaluation. Appropriate therapy is necessary for treatment and prevention of paralytic episodes. Although the prognosis is usually good, in case of misdiagnosis and maltreatment this condition may be fatal.