Hypokalemic Periodic Paralysis in Hyperthyroidism–Rare Event

Thyrotoxic periodic paralysis is a rare condition with only sporadic cases described in the medical literature. It occurs as a neuromuscular disorder characterized by recurrent attacks of severe muscle weakness associated with low serum potassium and thyrotoxicosis. We report the unusual case of a 21-year-old man who complained of lack of strength in his legs and generalized weakness in his upper and lower limbs, severe hypokalemia was detected during routine laboratory examinations. Thyrotoxic periodic paralysis as the underlying cause was suggested by suppressed thyroid stimulating hormone, elevated free T3 and free T4, and the presence of thyroid stimulating hormone-receptor antibodies. Treatment with intravenous potassium, an antithyroid drug, nonspecific beta-blocker, and anxiolytic agents resulted in a rapid resolution of symptoms. We also discuss the pathogenesis and characteristics of this rare disorder by reviewing the current medical literature.