title: [A clinical review of 449 cases with fever of unknown origin].
abstract: OBJECTIVE
  To investigate the causes of fever of unknown origin (FUO).
  
  
  METHODS
  The clinical data were retrospectively analyzed from patients with FUO hospitalized in Peking Union Medical College Hospital from January 2000 to December 2003. During that period of time, 449 cases fulfilled the criteria of FUO.
  
  
  RESULTS
  Out of the 449 FUO cases, definite diagnosis was eventually achieved in 387 patients (86.9%). The most common causes of FUO were infectious diseases (56.8%), with tuberculosis accounting for 43.6% of cases of infection. Seventy-six patients were suffered from collagen vascular diseases (CVD): with Still's disease, systemic lupus erythematosus and vasculitis accounting for 34.2% (26/76), 18.4% (14/76) and 13.2% (10/76) of the this category, respectively. 16.5% (64/449) of the FUO cases were diagnosed as malignancy. Miscellaneous causes were found in 7.0% of the FUO cases. However, no definite diagnosis had been made in the remaining 62 (13.8%) cases until they discharged from the hospital.
  
  
  CONCLUSIONS
  In most FUO cases the causes can be diagnosed eventually after careful analysis of clinical data. While infectious diseases, especially tuberculosis, were still the most common causes of FUO, CVD and malignancy were also major causes of FUO and the incidence of malignancy were increased with the time.
authors.affiliation: Department of Infectious Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China. mxjun@263.net
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Ma
authors.forename: Ai-xia
authors.initials: AX
authors.lastname: Wang
authors.forename: Guo-hua
authors.initials: GH
authors.lastname: Deng
authors.forename: Rui-yuan
authors.initials: RY
authors.lastname: Sheng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003240:Connective Tissue Diseases / Q000150:complications; D005260:Female; D005335:Fever of Unknown Origin / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D007239:Infections / Q000150:complications; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D012189:Retrospective Studies