Lesch-Nyhan syndrome (LNS) is a disease characterized by a reduced ability to recycle purines, leading to increased de novo purine synthesis and uric acid production. Patients classically present with an array of hyperuricemic, neurologic, and behavioral symptoms. In this report, we describe a 26-year-old male with a history of LNS and recurrent fevers of unknown origin who presented to the emergency department (ED) with a fever, hypotension, and hypernatremia. We suspect that our patient's presentation was caused by autonomic instability in the setting of LNS leading to excessive free water loss. This report highlights a rare but life-threatening manifestation of LNS.