Hypokalemic paralysis following administration of intravenous methylprednisolone in a patient with Graves' thyrotoxicosis and ophthalmopathy

Glucocorticoids are commonly used in the treatment of patients with thyroid disorders, in particular Graves' ophthalmopathy. Thyrotoxic hypokalemic periodic paralysis (TPP) is an infrequent but potentially serious condition characterised by recurrent episodes of weakness associated with hypokalemia. We describe the development of acute hypokalemic paralysis in a middle-aged Caucasian man with recently diagnosed thyrotoxicosis and severe, active Graves' opthalmopathy who developed progressive flaccid paralysis 12 hours following intravenous administration of methylprednisolone. Rechallenge with the same dose after the patient had been rendered euthyroid did not provoke TPP. Clinicians should exercise caution when administering high-dose glucocorticoids during thyrotoxicosis as there is a risk of provoking hypokalemic paralysis in susceptible patients.