Thyrotoxic Periodic Paralysis: A Review of Cases in the Last Decade

Objective: Thyrotoxic periodic paralysis (TPP) is a rare condition characterized by severe muscle weakness and life-threatening hypokalemia in uncontrolled hyperthyroidism. Given the life-threatening potential of this condition, it is important to better characterize its presentation, management, and likelihood for complications to aid in quicker diagnosis and optimize medical management. Methods: We retrospectively reviewed cases of TPP that occurred at 3 hospitals from 2004 to 2014. Patients included were those presenting with weakness and hypokalemia who were found to have thyrotoxicosis. Results: Nine cases of TPP were identified including 7 Hispanic males and 1 African American male. Six patients developed complications of therapy with rebound hyperkalemia. TPP was the first presentation of thyrotoxicosis for 5 patients. The remaining 4 patients with known hyperthyroidism admitted to several weeks of medication nonadherence prior to their episode of TPP. Conclusion: Our study suggests that TPP may be more common in other ethnicities than previously described, with the majority of our cases occurring in Hispanic males. Physicians should be wary of rebound hyperkalemia as it is a common complication of therapy. Because hypokalemia is related to a transcellular shift and not total body depletion of potassium, supplementation with potassium should be done slowly. Early concurrent treatment with nonselective beta-blockers should be employed, and standardized hospital potassium replacement protocols should be avoided. TPP may be the first sign of thyrotoxicosis. All patients with weakness and hypokalemia should undergo thyroid function testing. Abbreviations: ICD International Classification of Disease ICU intensive care unit TPP thyrotoxic periodic paralysis