Introduction: Despite its rare occurrence in Caucasians, thyreotoxic periodic paralysis should be evoked in young male Caucasians presenting with episodes of pseudo-paralytic hypokalemia.
Observation: A 37 year-old Caucasian was admitted in intensive care for an acute episode of hypotonic tetraplegia and hypokalemia during which laboratory tests revealed hyperthyroidism due to Basedow's disease. The clinical course was rapidly favourable after a small dose of intravenous potassium. Antithyroid treatment avoided any new occurrence of similar episodes.
Discussion: In Caucasians, sporadic acute paralysis with hypokalemia requires testing for hyperthyroidism. Though it is well know that hypokalemia results from potassium intracellular shift, the underlying mechanism remains poorly elucidated. Treatment includes potassium administration with caution and/or beta blockers but the specific treatment is that of hyperthyroidism.