Periodic drop thumb, hypokalemia and adrenal adenoma

To report an unusual involvement of focal distal muscles but not proximal muscles in a patient with hypokalemic periodic paralysis [hypoPP]. A middle-aged woman presented with episodic weakness of the bilateral thumbs lasting for 2 years. Hypokalemia and a left adrenal mass were subsequently found. Her weakness subsided after surgical removal of the adrenal mass, which was pathologically proven to be an adrenal adenoma. The findings for this patient should alert physicians to consider focal distal motor paresis due to hypoPP. A preexisting occult trauma may predispose to paralysis at an atypical location in secondary hypoPP