[Fever of unknown origin, comparing two series with 26 years of difference].

Introduction: 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.