Relationships between Causes of Fever of Unknown Origin and Inflammatory Markers: A Multicenter Collaborative Retrospective Study.

OBJECTIVE: Although inflammatory markers, such as the white blood cell (WBC) count, erythrocyte sedimentation rate (ESR) and levels of C-reactive protein (CRP) and procalcitonin, are widely used to differentiate causes of fever of unknown origin (FUO), little is known about the usefulness of this approach. We evaluated relationships between the causes of classical FUO and the levels of inflammatory markers. METHODS: A nationwide retrospective study including 17 hospitals affiliated with the Japanese Society of Hospital General Medicine was conducted. PATIENTS: This study included 121 patients ≥18 years old diagnosed with "classical FUO" (axillary temperature ≥38.0°C at least twice over a ≥3-week period without elucidation of the cause on three outpatient visits or during three days of hospitalization) between January and December 2011. RESULTS: The causative disease was infectious diseases in 28 patients (23.1%), non-infectious inflammatory disease (NIID) in 37 patients (30.6%), malignancy in 13 patients (10.7%), other in 15 patients (12.4%) and unknown in 28 patients (23.1%). The rate of malignancy was significantly higher for a WBC count of <4,000/µL than for a WBC count of 4,000-8,000/µL (p=0.015). Among the patients with a higher WBC count, the rate of FUO due to NIID tended to be higher and the number of unknown cases tended to be lower. All FUO patients with malignancy showed an ESR of >40 mm/h. A normal ESR appeared to constitute powerful evidence for excluding a diagnosis of malignancy. In contrast, the concentrations of both serum CRP and procalcitonin appeared to be unrelated to the causative disease. CONCLUSION: The present study identified inflammatory markers that should be considered in the differential diagnosis of classical FUO, providing useful information for future diagnosis.

Analysis of 256 cases of classic fever of unknown origin.

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 2004-2012, compared to 1994-2003, infections 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.

Diagnostic workup for fever of unknown origin: a multicenter collaborative retrospective study.

OBJECTIVE: Fever of unknown origin (FUO) can be caused by many diseases, and varies depending on region and time period. Research on FUO in Japan has been limited to single medical institution or region, and no nationwide study has been conducted. We identified diseases that should be considered and useful diagnostic testing in patients with FUO. DESIGN: A nationwide retrospective study. SETTING: 17 hospitals affiliated with the Japanese Society of Hospital General Medicine. PARTICIPANTS: This study included patients ≥18 years diagnosed with 'classical fever of unknown origin' (axillary temperature ≥38°C at least twice over a ≥3-week period without elucidation of a cause at three outpatient visits or during 3 days of hospitalisation) between January and December 2011. RESULTS: A total of 121 patients with FUO were enrolled. The median age was 59 years (range 19-94 years). Causative diseases were infectious disease in 28 patients (23.1%), non-infectious inflammatory disease in 37 (30.6%), malignancy in 13 (10.7%), other in 15 (12.4%) and unknown in 28 (23.1%). The median interval from fever onset to evaluation at each hospital was 28 days. The longest time required for diagnosis involved a case of familial Mediterranean fever. Tests performed included blood cultures in 86.8%, serum procalcitonin in 43.8% and positron emission tomography in 29.8% of patients. CONCLUSIONS: With the widespread use of CT, FUO due to deep-seated abscess or solid tumour is decreasing markedly. Owing to the influence of the ageing population, polymyalgia rheumatica was the most frequent cause (9 patients). Four patients had FUO associated with HIV/AIDS, an important cause of FUO in Japan. In a relatively small number of cases, cause remained unclear. This may have been due to bias inherent in a retrospective study. This study identified diseases that should be considered in the differential diagnosis of FUO.

Predicting bacteremia based on nurse-assessed food consumption at the time of blood culture.

BACKGROUND: Bacteremia and its complications are important causes of morbidity and mortality in hospitalized patients. However, the yield of blood cultures is relatively low, with many false-positive results from bacterial contamination. METHODS: We investigated the relationship between patient food consumption and the presence of bacteremia. This was an observational analysis of a cohort of 1179 patients who underwent blood culture analysis between January 2005 and December 2009. Patients with anorexia-inducing conditions, such as gastrointestinal illness and malignant disease treated with chemotherapy, were excluded. Food consumption was rated by nurses as the percentage of food consumed during the meal preceding the blood culture. Groupings were as follows: low consumption (<50%), moderate (>50% to <80%), and high (>80%). RESULTS: Low consumption was observed in 39.8% of patients, moderate in 17.8%, and high in 41.6%. The average body temperature was 38.1 ± 1.1°C. Bacteremia was present in 18.5%, 3.9%, and 1.4% of patients in the low, moderate, and high food consumption groups, respectively. The negative predictive value was 98.3%, suggesting that bacteremia is very unlikely in the setting of good food intake. CONCLUSION: Bacteremia is an unlikely occurrence in hospitalized patients who maintain adequate food consumption at the time of blood culture.