A patient with acute quadriparesis in the emergency department: Unmasking the diagnosis through electrocardiography.

Electrolyte abnormalities may masquerade as acute neurological or cardiac emergencies in the emergency department (ED). In such atypical presentations, a timely bedside electrocardiography (ECG) often provides the earliest and most critical clue, facilitating an accurate diagnosis, guiding appropriate management, and improving patient outcomes. A 32-year-old male presented with rapidly evolving flaccid quadriparesis without sensory or autonomic involvement. A bedside ECG provided a critical clue, revealing a Mobitz type I block with ischemia-mimicking ST-T changes and prominent U waves. This prompted urgent testing, which confirmed profound hypokalemia and hypomagnesemia. Swift intravenous repletion reversed both paralysis and conduction abnormalities within 72 h. Although electrolyte abnormalities are known to produce typical ECG changes, their presentation with conduction disturbances such as Wenckebach block is rare and easily misinterpreted as ischemia or structural heart disease. Prompt recognition of these atypical ECG findings at the bedside is critical to avoid unnecessary invasive workups and to initiate lifesaving electrolyte correction.