Thyrotoxic periodic paralysis induced by pulse methylprednisolone.

We present a young Thai man who developed acute flaccid paralysis after receiving pulse methylprednisolone for chronic inflammatory demyelinating polyneuropathy. Hypokalemia from intracellular shift was confirmed by calculation of transtubular potassium gradient (TTKG). His muscle strength and serum potassium fully recovered with a small amount of potassium replacement. Graves' disease was subsequently diagnosed and treated with radioactive iodine. We suggest that acute paralysis after the use of steroids should raise a suspicion of thyrotoxic periodic paralysis (TPP). The potential mechanisms of steroid-induced TPP are discussed.