Introduction: Patients in the emergency department may experience sudden decompensation despite initially appearing stable.

Case Presentation: A 37-year-old transgender man presented to the emergency department (ED) with several months of fevers, myalgias, and weight loss. The patient acutely became febrile, tachycardic, and hypotensive after an initially reassuring assessment in the ED.

Discussion: This case takes the reader through the differential diagnosis and work-up of the decompensating patient initially presenting with subacute symptoms.