Longstanding Phenytoin Use as a Cause of Progressive Dyspnea.

A 54-year-old South African man with a medical history of type 2 diabetes mellitus, seizure disorder, OSA, and latent TB presented to the ER with gradually progressive dyspnea over months. He also reported occasional dry cough and fatigue at presentation but denied fever, chills, chest pain, leg swelling, palpitations, or lightheadedness. He was treated with a course of levofloxacin for presumed community-acquired pneumonia as an outpatient without improvement and had tested negative for COVID-19.