Analysis of 256 Cases of Classic Fever of Unknown Origin

Abstract

Objective The causes of fever of unknown origin (FUO) vary depending on the region and time period. We herein present a study of patients with classic FUO where we investigated differences based on patient background factors, such as age and causative diseases, and changes that have occurred over time. Methods We extracted and analyzed data from the medical records of 256 patients ! 18 years old who met the criteria for classic FUO and were hospitalized between August, 1994 and December, 2012. Results The median age of the patients was 55 years (range: 18-94 years). The cause of FUO was infection in 27.7% of the patients (n=71), non-infectious inflammatory disease (NIID) in 18.4% (47), malignancy in 10.2% (26), other in 14.8% (38), and unknown in 28.9% (74). The most common single cause was human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) (n=17). NIID and malignancy were more common in patients ! 65 years old than in patients <65 years old. During 2004During -2012During , compared to 1994During -2003 and "other" causes were decreased, whereas NIID, malignancy, and unknown causes were increased. Conclusion FUO associated with HIV/AIDS is increasing in Japan. In addition, as in previous studies in Japan and overseas, our study showed that the number of patients in whom the cause of FUO remains unknown is increasing and exceeds 20% of all cases. The present study identified diseases that should be considered in the differential diagnosis of FUO, providing useful information for the future diagnosis and treatment of FUO.

Epidemiology of Causes of Fever of Unknown Origin in an Academic Center: A Five-Year Evaluation from 2009 to 2014

“…However, the findings from the current study show almost similar numbers of patients diagnosed with infections and NIIDs. This trend can partly be explained by the exclusion of HIV infected patients, but still comparable to the results from other studies since the 1930's that show a decline in infectious causes of FUO (10,14). The considerable proportion of "unknown" cases in the patient population is also analog to the concerns expressed elsewhere, specifically in the developed world (Horowitz).…”

“…Lymphoma is the common malignancy presenting with FUO; a similar pattern has been reported in a previous evaluation in our setting (21). Considering the insidious nature of lymph node involvement in hematologic malignancies, the findings of other studies confirm the same picture (10).…”

“…The causes and different approaches taken to reach a definitive diagnosis have been widely investigated in the literature (all + Louizidou). For a long time, infectious agents have been the primary cause of FUO (7)(8)(9)(10)(11). Despite the widespread use of antimicrobials, there are rare agents that may present with chronic unexplained fever and require high clinical suspicion (12).…”

Kocuria kristinae septic arthritis associated with infectious endocarditis in a hemodialysis patient with diabetes mellitus: a case report and literature review

“…Because ESRD and diabetes mellitus can both lead to an immunocompromised status and increase susceptibility to unusual infections, [19]. In this context, Japanese investigators have reported that the causes of fever of unknown origin (FUO) are infection (27.7 %), non-infectious inflammatory disease (18.4 %), malignancy [20]. Thus, given the frequency of an unknown cause of FUO, we usually use empirical antibiotics to treat infections of unknown origin until culture results are available.…”

Diagnostic Value of Common Inflammatory Markers on Fever of Unknown Origin

“…As diagnostic methods and tools are developed, most patients can reach a definite diagnosis. However, it is reported that 7z to 51z of FUO cases remain undiagnosed (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). There are more than 200 causes for FUO (14).…”