Summary

Thyrotoxic periodic paralysis (TPP) is a well-known complication of hyperthyroidism, characterised by recurrent flaccid paralysis with hypokalaemia. To date, only five cases of this rare disorder have been reported in Saudi Arabia. Here, we report an additional case involving a 25-year-old Saudi man who presented with lower limb paralysis and severe hypokalaemia. Clinically, he showed symptoms and signs suggestive of Graves’ disease, which was confirmed by laboratory investigations. Carbimazole, a beta-blocker and potassium replacement were administered, resulting in dramatic improvement of the TTP. This case emphasises the importance of considering TPP in patients with acute muscle weakness and the importance of promptly initiating treatment and preventing relapse of TPP.