Fever of Undetermined Origin

The spectrum of underlying diseases, which those caring for patients with fever of undetermined origin (FUO)¹ must initially consider, remains sufficiently complex to challenge all clinicians from neophyte to maven. Indeed, students, house officers, and attending physicians alike tend to view these cases as rather unique opportunities to unleash their full complement of clinical and laboratory skills. However, the ever-proliferating array of diagnostic procedures to which patients with FUO can be subjected in pursuit of a treatable illness makes it imperative to meticulously plan and individualize all diagnostic evaluations. Thus, the review by Esposito and Gleckman in the May Archives (139:575-579, 1979) serves as a timely reminder of the importance of a considered, step-by-step approach to patients with FUO. These authors put into perspective the diagnostic problems of persistent fever as viewed first from the physician's initial patient contact in the office and then in the in-hospital setting. Esposito