Hypokalemic periodic paralysis is a rare and dramatic complication of hyperthyroidism. This series summarizes the clinical and metabolic features of 10 patients who presented to the Western and Sunshine hospitals in Melbourne, Australia, between 1997 and 2002 with thyrotoxic periodic paralysis (TPP). TPP classically presents with proximal lower-limb weakness in the setting of a low potassium level and biochemical evidence of thyrotoxicosis: low thyroid-stimulating hormone levels along with elevated free thyroxine (FT4) or free triiodothyronine (FT3). The challenge for emergency physicians is to recognize the association with thyroid disease, since features of hyperthyroidism may not be apparent on history and examination. Acute treatment with potassium supplements and long-term management is aimed at achieving an euthyroid state. Thyrotoxic periodic paralysis is more common in Asian populations; however, increasing immigration from Asia will lead to higher TPP prevalence in Western countries.
