Endocrine Abstracts

Background: Hypokalemic thyrotoxic periodic paralysis (HTPP) is a rare but potentially life-threatening complication of hyperthyroidism, characterized by episodic muscle weakness or paralysis. It is primarily associated with Asian populations, although cases have been reported worldwide. The exact pathophysiology of HTPP remains unclear, but it is believed to involve a combination of factors, including hyperthyroidism, genetic predisposition and various triggers such as stress, infection, medications including steroids.

Case Presentation: A 51-year-old male Asian presented to the emergency department with acute onset of generalized weakness affecting both upper and lower limbs. He mentioned receiving an intra-articular corticosteroid injection several hours before the onset of weakness for knee pain in GP Surgery. Physical examination revealed global weakness with reduced power in all limbs. Deep tendon reflexes were diminished. Laboratory tests showed Potassium levels of 1.5mmol/L (3.5-5.3), Thyroid functions TSH <0.01mIU (0.35-4.94), T4 24 pmol/l (9-19.1), T3 22.4 pmol/l (2.4-6), TSH receptor antibody came back positive as 5.2IU/l(0-2.9). The patient was managed with Intravenous potassium, oral Carbimazole 40 mg and propranolol. His weakness was subsequently improved following potassium replacement. A NM thyroid scan revealed diffuse increased uptake with no nodules which was keeping with graves’ disease. On follow up, thyroid functions were improved as T4 13.5, T3 5.5 hence, Carbimazole was reduced to 20 mg. A 6 month follow up revealed complete normalization of thyroid function as TSH 0.36, T4 11.

Conclusion: This case highlights the importance of recognizing HTPP as a potential complication of hyperthyroidism, especially in patients with risk factors such as Asian ethnicity and recent exposure to triggers. Early diagnosis and prompt treatment are essential for preventing severe complications such as arrythmias and ensuring a favourable outcome. Further research is needed to elucidate the precise mechanisms underlying steroid-induced HTPP in Graves’ disease.