Keito Torikai

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.

Investigation on prediction formulae for calculating erythrocyte sedimentation rate

Dear Editor: The erythrocyte sedimentation rate (ESR) is commonly determined in laboratory blood testing and is often elevated in patients with underlying systemic disorders. In 1983, Miller et al.1 clarified the upper limits of ESR and, since then, these parameters have been widely applied in clinical practice. In a study of the upper limits of ESR based on 26 836 healthy men and 1076 nonpregnant healthy women, Miller et al.1 reported that the maximum values varied in 98% of the study cohort, increasing from 11 mm/h in young men to around 30 mm/h at the age of 65. The corresponding values for women were around 20 and 36 mm/h, respectively. They suggested that the upper ESR limit can be calculated by the following formulae: men, age in years/2; women (age in years + 10)/2. However, no reports have addressed the integrity of these limits. Although some reports have explored the application of these limits for patients aged 2065 years in routine health screening, there has been no mention of the applicability in elderly patients. In 1996, Wetteland et al.2 reported that there was a significant association between ESR level and age (range 2090 years). In 1993, Gillum reported differences in ESRs between Caucasians and Negro races, independent of age, hemoglobin concentration, and certain chronic diseases.3 However, there are currently no reports on differences in ESRs between Asians and other races. Therefore, the aim of this investigation was to assess the normal maximum range of ESR as described by Millar et al.1 and to determine whether this rule is applicable to Asians and the elderly. We retrospectively reviewed the records of 249 patients (85 males and 164 females; mean age, 75.0 years; age range, 6591 years) who were examined at the outpatient department of St. Marianna University Hospital from September 2012 to August 2013. Requirements of participation for this study were age >65 years, Creactive protein ≤0.03 mg/L, and clinical stability (vital signs were stable and afebrile in a few months). Patients with affecting factors for values of ESR were excluded from subjects of this investigation (e.g, anemia, hyper gammopathy, disseminated intravascular coagulation syndrome, polycythemia). The study was approved by ethical committee of St. Marianna University (No. 3128). The median ESR value of males and females was 6 mm/h (range, 131 mm/h) and 12 mm/h (range, 245 mm/h), respectively. The overall median difference between the measured and predicted ESRs was 30 mm/h (range, 150.5 mm/h), 30 mm/h (range, 150.5 mm/h) for males, and 30 mm/h (range, 12.543.5 mm/h) for females. The results of our study indicated that the Millar’s rule for calculating normal maximum ESR values is applicable to patients aged >65 years and Asians. However, a limitation of this study was the lack of control groups for age and race. Individual differences in ESR present an important shortcoming. Various factors, such as age and gender among others, affect ESR.3-5 Thus, a formula to calculate ESR is essential. This study was conducted with Japanese healthy patients includes elderly. Most of the measured values were lower than the predicted value. Our investigation showed that actual ESR mostly fits within the range of the predicted values and may be applicable to both Asians and the elderly (Figures 1 and 2). Erythrocyte sedimentation rate can be used as an index to analyze and evaluate the treatment period, especially in cases that require