An intriguing, and somewhat frightening, case of an anion gap metabolic acidosis.S2D: The Symptom to Diagnosis Podcast presents case-based discussions of signs, symptoms, and diagnostics tests to improve clinical reasoning and evidence-based practice. Sponsored by McGraw Hill, S2D features Scott D. C. Stern, MD, FACP Professor of Medicine and Clinical Director of Clinical Pathophysiology and Therapeutics at the University of Chicago Pritzker School of Medicine, and Adam S. Cifu, MD, FACP  Professor of Medicine and Associate Dean for Medical School Academics at the University of Chicago Pritzker School of Medicine.