Subclinical hyperthyroidism presenting with hypokalemic periodic paralysis in the emergency department

Subclinical hyperthyroidism (SH) is a condition in which blood levels of Thyroxine (T4) and Triiodothyronine (T3) are normal in the presence of low levels of thyroid-stimulating hormone (TSH). Patients with SH have either no symptoms or mild nonspecific symptoms. Hypokalemic periodic paralysis (HPP) is one of the rare presentations of overt hyperthyroidism; however, only a few cases are reported to date to occur with SH. This case report presents a case of a young Asian male who was admitted to the emergency department (ED) with paralysis of the lower extremities that progressed to the upper extremities and neck muscles in 2 days. Clinically, he was euthyroid; however, his thyroid profile revealed normal levels of T3 and T4 with undetectable TSH levels. This case report aims to add to the limited literature on SH that presents with HPP in the ED.