Endocrine Abstracts

Introduction: Thyrotoxic hypokalemic paralysis is a disorder most commonly seen in Asian men. The condition primarily affects the lower extremities. The main characteristic features of this condition are elevated thyroid hormones, hypokalemia and proximal muscle weakness or paralysis.

Cases

Case 1: A 28 year old patient presented to emergency department with 3 day history of progressive weakness of both lower limbs which made him unable to walk. Later the weakness progressed to upper limbs.

Case 2: A 24 year old male presented with a history of recurrent cramps and spasms of the lower limb muscles for a month. He also had a history of acute onset weakness of both lower limbs for 2 days.

Case 3: A 35 year old male presented with repeated episodes of weakness of lower limbs. He was hospitalized thrice for the same complaints and hypokalemia was documented in each episodes.

The laboratory results were notable for a very low potassium level. After excluding other possible causes, thyroid function was done in these cases. T₃ and T₄ were high and TSH was suppressed in all the three. Technituim scan showed diffuse increased uptake in cases 1 and 2 suggesting Graves’ disease. Third case had patchy uptake suggesting MNG. They were started on Carbimazole 30 mg/day and propranolol 60 mg/day. The muscle weakness improved gradually and were discharged on anti-thyroid medications.

Discussion: Thyrotoxic paralysis has a predilection for males of Asian descent. The pathogenesis is not clear but enhanced activity of Na+, K+-ATPase might be the possible etiology. Definitive treatment is correction of the thyrotoxic state along with cautious potassium replacement during the attack.

Conclusion: Hypokalemic paralysis must be included in the differential diagnosis of acute muscle weakness and thyrotoxicosis should be kept in the differential diagnosis especially in Asian men.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.