title: [Fever of unknown origin, comparing two series with 26 years of difference].
abstract: BACKGROUND
  Fever of unknown origin (FUO) remains a syndrome with difficult approach and changing spectrum. Our aim was to compare two series of FUO patients seen at the Department of Internal Medicine, Hospital de Especialidades Centro Medico La Raza, Mexico City.
  
  
  METHODS
  Data from FUO series from 1979-87 were compared with those from 2004-14 series. We analyzed demographic data, final diagnoses, and diagnostic tests used. We report median and range for numerical variables and frequencies for nominal data, bivariate analysis was done with chi-square or Fisher´s test as needed using SPSS version 17.0 for MAC and open-epi version 3.7.
  
  
  RESULTS
  One hundred twenty seven patients were included in the 1979-87 series and 118 in the 2004-14 series. There were more non-infectious inflammatory diseases (p=0.0004) and less infectious diseases (p=0.024) in the 2004-14 series. We observed no significant differences in neoplastic diseases and undiagnosed cases between the two series. Laboratory tests and their diagnostic utility were similar in both series, but image studies were less useful in the 2004-14 series. Biopsy and laparotomy remained as frequent and useful tools in both series.
  
  
  CONCLUSIONS
  The recent series had more non-infectious inflammatory diseases and less infectious causes of FUO. Invasive studies remain as useful diagnostic aids in a significant number of cases.
authors.affiliation: Departamento de Medicina Interna, Hospital de Especialidades, Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Distrito Federal. moi.casarrubias@gmail.com.
authors.forename: Moisés
authors.initials: M
authors.lastname: Casarrubias-Ramírez
authors.forename: José Alfredo
authors.initials: JA
authors.lastname: Alfaro-Mejía
authors.forename: Juan
authors.initials: J
authors.lastname: De Santiago-Leaños
authors.forename: Sergio Alberto
authors.initials: SA
authors.lastname: Mendoza-Álvarez
authors.forename: Luis Francisco
authors.initials: LF
authors.lastname: Pineda-Galindo
authors.forename: Olga Lidia
authors.initials: OL
authors.lastname: Vera-Lastra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005335:Fever of Unknown Origin / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D007239:Infections / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D007249:Inflammation / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D012189:Retrospective Studies; D055815:Young Adult
keywords: Fever of unknown origin; Infectious diseases; Neoplastic diseases; Non-infectious inflammatory diseases