Paralysis to Analysis: Unmasking Thyrotoxic Periodic Paralysis in a Middle-Aged Male Patient With Undiagnosed Graves Disease.

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism characterized by sudden-onset muscle weakness and hypokalemia due to intracellular potassium shifts. It most commonly affects young Asian men and is rarely seen in older adults or non-Asian populations. We present the case of a 52-year-old Hispanic male patient who experienced episodic bilateral limb weakness and falls over several months, ultimately diagnosed as TPP secondary to previously undiagnosed Graves' disease. Despite normal neurologic imaging and no overt hyperthyroid symptoms, thyroid function testing revealed severe thyrotoxicosis. Treatment with potassium replacement, methimazole, and propranolol led to the resolution of symptoms. This case highlights the importance of maintaining a high index of suspicion for TPP in patients with recurrent weakness, even when demographic and clinical features are atypical.