Studies on pathogeny and diagnosis of fever of unknown origin

Objective To analyze the etiology, clinical characteristics and diagnostic methods of fever of unknown origin (FUO), so as to provide a reference for the diagnosis and treatment of FUE. Methods The clinical data of 340 patients with FUO admitted in Tongji Hospital from Jan. 2005 to Dec. 2010 were retrospectively analyzed. The relationship between etiology and gender, age of the patients, and course of fever were comprehensively evaluated, and the diversity of disease spectrum was also analyzed. Results Among the 340 patients analyzed, 295(86.76%) the diagnosis was definitely made. As to the etiology, 150(50.85%) were suffering from infectious diseases, 145(49.15%) non-infectious diseases, and in 45(13.24%) the etiology remained unknown till they were discharged from hospital. Among all of the patients, 186(54.71%) were male and 154(45.29%) were female. No significant difference existed in the ratio of disease distribution between male and female patients, but the incidence of connective tissue disease was significantly higher in female patients than in male patients, while the incidence of lymphoma was significantly higher in male patients than in females. As to the age distribution of the disease, 66 patients (19.41%) were younger than 20 years old, 98 patients (28.82%) were 21-40, 136(40.00%) were 41-60, and 40(11.76%) were older than 60. The mean age of patients suffering from solid tumors was the highest (48.4±17.2 years), and that of adult Still disease was youngest (27.4±11.9 years). The course of fever in 202 patients (59.41%) was shorter than 4 weeks, that of 50 patients (14.71%) was 4-8 weeks, and in 88 patients (25.88%) it was longer than 8 weeks. Febrile course was longest in patients suffering from connective tissue disease, lymphoma and tuberculosis. Conclusions Most of the patients with FUO could be definitely diagnosed prudent inquiry of history, followed by scrupulous physical examination, aided by appropriate instrumental examination, most cases of FUO could be definitely diagnosis. Among these patients, infectious diseases remain the main causes of FUO. The disease spectrum will be diverse due to different gender, age and course of fever.