Fever of unknown origin: a review of 80 patients from the Shin'etsu area of Japan from 1986-1992

Fever of unknown origin (FUO) in children: a single-centre experience from Beijing, China

OBJECTIVE

To date, there is no standard diagnostic practice to identify the underlying disease-causing mechanism for paediatric patients suffering from chronic fever without any specific diagnosis, which is one of the leading causes of death in paediatric patients. Therefore, we aimed this retrospective study to analyse medical records of paediatric patients with fever of unknown origin (FUO) to provide a preliminary basis for improving the diagnostic categories and facilitate the treatment outcomes.

DESIGN

A retrospective study.

SETTING

Beijing Children's Hospital.

PARTICIPANTS

Clinical data were collected from 1288 children between 1 month and 18 years of age diagnosed with FUO at Beijing Children's Hospital between January 2010 and December 2017.

INTERVENTIONS

According to the aetiological composition, age, duration of fever and laboratory examination results, the diagnostic strategies were analysed and formulated.

PRIMARY AND SECONDARY OUTCOME MEASURES

The statistical analyses were carried out using SPSS V.24.0 platform along with the χ² test and analysis of variance (p<0.05).

RESULTS

The duration of fever ranged from 2 weeks to 2 years, with an average of 6 weeks. There were 656 cases (50.9%) of infectious diseases, 63 cases (4.9%) of non-infectious inflammatory diseases (NIIDs), 86 cases (6.7%) of neoplastic diseases, 343 cases (26.6%) caused by miscellaneous diseases and 140 cases (10.9%) were undiagnosed. With increasing age, the proportion of FUO from infectious diseases gradually decreased from 73.53% to 44.21%. NIID was more common in children over 3 years old, and neoplastic diseases mainly occurred from 1 to 6 years of age. Among miscellaneous diseases, the age distribution was mainly in school-aged children over 6 years. Respiratory tract infection was the most common cause of FUO in children, followed by bloodstream infections. Bacterial infection was the most common cause in children with less than 1 year old, while the virus was the main pathogen in children over 1 year old.

CONCLUSIONS

The diagnosis of neoplastic diseases and miscellaneous diseases-related diseases still depends mainly on invasive examination. According to our clinical experience, the diagnostic process was formulated based on fever duration and the type of disease. This process can provide a guide for the diagnosis and treatment of paediatric FUO in the future.

Adult-onset Still's disease in focus: Clinical manifestations, diagnosis, treatment, and unmet needs in the era of targeted therapies

BACKGROUND

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology, characterized by a clinical triad of high spiking fever, arthralgia (± arthritis), and evanescent skin rash. Management of AOSD poses several challenges, including difficulty in diagnosis and limited therapeutic options. In this review, we examined whether AOSD and systemic juvenile idiopathic arthritis (SJIA) represent a continuum of the same disease. We also explored the latest available evidence related to prevalence, clinical and laboratory manifestations, complications, diagnostic challenges, novel biomarkers, and treatment options in the era of biologics and identified the unmet needs of patients with AOSD.

METHODS

A comprehensive systematic literature search was performed in the Embase and MEDLINE (via PubMed) literature databases. The search was limited to human studies published in English from inception up to March 2020. Additionally, abstracts presented at various conferences were screened and hand searches were performed. Publications were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 123 publications were identified through the literature search, majority of which were case series and retrospective observational studies. AOSD and SJIA are widely considered part of the same disease spectrum owing to similarities in their clinical and biological features. The clinical presentation of AOSD is highly variable, accompanied by a broad spectrum of disease manifestations. Recent evidence suggests that the AOSD disease course can be classified into two distinct categories: "systemic" and "articular." Furthermore, AOSD patients may experience various life-threatening complications, such as macrophage activation syndrome - reported in as high as 23% of AOSD patients and considered to be the most severe complication characterized by a high mortality rate. The ambiguity in presentation and lack of serologic markers make the diagnosis of AOSD difficult, often leading to a delay in diagnosis. Given these limitations, the Yamaguchi and Fautrel criteria are the most widely used diagnostic tools in clinical practice. It has been observed that a clinical diagnosis of AOSD is generally reached by exclusion while investigating a patient with fever of unknown origin. Recent advances have demonstrated a major role of proinflammatory cytokines, such as interleukin (IL)-1, IL-6, IL-18, and IL-37, and other biomarkers in the pathogenesis and management of AOSD. Owing to the rarity of the disease, there are very limited clinical trials evaluating management strategies for AOSD. The current AOSD treatment paradigm includes non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids initially, conventional synthetic disease-modifying anti-rheumatic drugs in steroid-refractory patients, and biologics in those resistant to conventional treatment. Only a few country-specific guidelines for the management of AOSD have been published, and a treat-to-target approach, as previously recommended for SJIA, is still lacking. Canakinumab is the only FDA-approved biologic for the treatment of AOSD.

CONCLUSION

Emerging evidence supports that AOSD and SJIA represent a continuum of the same disease entity. Despite advancements in the understanding of AOSD, it continues to pose a substantial burden on patients and the healthcare systems, and substantial unmet needs exist across key domains such as the pathway to diagnosis, use of biomarkers in clinical practice, and standardized treatment strategies. Further research and collaboration is crucial for optimizing the diagnosis and management of AOSD patients.

The changing pattern of fever of unknown origin in the Republic of North Macedonia

INTRODUCTION

The study aimed to compare the etiologic spectrum of diseases causing fever of unknown origin (FUO) and methods for definitive diagnosis in a tertiary care hospital in the Republic of North Macedonia during two different time periods.

PATIENTS AND METHODS

There were analysed retrospectively the causes for FUO and final diagnostic approaches in 185 patients with classic FUO that were treated at the University Hospital for Infectious Diseases in Skopje during two time periods. Seventy nine patients were treated during 1991 to 1995 and 106 patients during 2011 to 2015.

RESULTS

When comparing these two periods, infections were present in 46.8% and 29.2% (p = 0.014), non-infective inflammatory disorders in 22.8% and 25.5% (p = 0.674), neoplasms in 10.1% and 13.2% (p = 0.522), miscellaneous in 8.9% and 12.3% (p = 0.461) and undiagnosed cases in 11.4% and 19.8% (p = 0.124), respectively. The most common causes for FUO during the first period were abscesses (8.9%), tuberculosis and systemic lupus erythematosus (7.6% each), whereas in the second period the commonest causes were adult onset Still disease and solid organ neoplasm (7.6% each), polymyalgia rheumatica, abscesses and visceral leishmaniasis (5.7% each). The newer imaging techniques and clinical course evaluation had superior diagnostic significance during the second period.

CONCLUSION

A changing pattern of diseases causing FUO during the examined periods was evident. Infections continue to be the most common cause but with decreasing incidence when compared to 20 years ago. Even nowadays clinical evaluation and follow-up still remain the vital diagnostic tools in determining the etiology of FUO.

Diagnostic approach for patients with unidentified fever according to the classical criteria of fever of unknown origin in the field of autoimmune disorders

Fever of unknown origin (FUO) is caused by various diseases, making differential diagnosis difficult. This study aimed to determine the clinical features of patients with FUO for use in daily medical practice. Medical records of patients who first visited our department for FUO between January 2008 and December 2017 were reviewed. We classified the diagnostic categories as infection, non-infectious inflammation, neoplasm, others, and unidentified through definitive diagnosis and compared the clinical characteristics of patients who fulfilled the criteria of classical FUO and those who did not. The most prevalent diseases in patients who fulfilled the criteria were adult-onset Still's disease, Behçet's disease (BD), and polymyalgia rheumatica, which do not have any specific image inspection or specific serological markers. BD and familial Mediterranean fever were most prevalent in patients who did not fulfill the criteria. All neoplasms fulfilled the criteria of classical FUO. The most useful diagnostic procedure was determined according to the criteria of each disease. The key factor that did not fulfill the criteria was periodic fever continuing for less than 3 weeks. When examining patients with FUO, we should strictly diagnose in accordance with the criteria of each disease and consider diseases that cause periodic fever.

Key diagnostic characteristics of fever of unknown origin in Japanese patients: a prospective multicentre study

OBJECTIVE

To identify the key diagnostic features and causes of fever of unknown origin (FUO) in Japanese patients.

DESIGN

Multicentre prospective study.

SETTING

Sixteen hospitals affiliated with the Japanese Society of Hospital General Medicine, covering the East and West regions of Japan.

PARTICIPANTS

Patient aged ≥20 years diagnosed with classic FUO (axillary temperature≥38.0°C at least twice within a 3-week period, cause unknown after three outpatient visits or 3 days of hospitalisation). A total of 141 cases met the criteria and were recruited from January 2016 to December 2017.

INTERVENTION

Japanese standard diagnostic examinations.

OUTCOME MEASURES

Data collected include usual biochemical blood tests, inflammatory markers (erythrocyte sedimentation rate (ESR), C reactive (CRP) protein level, procalcitonin level), imaging results, autopsy findings (if performed) and final diagnosis.

RESULTS

The most frequent age group was 65-79 years old (mean: 58.6±9.1 years). The most frequent cause of FUO was non-infectious inflammatory disease. After a 6-month follow-up period, 21.3% of cases remained undiagnosed. The types of diseases causing FUO were significantly correlated with age and prognosis. Between patients with and without a final diagnosis, there was no difference in CRP level between patients with and without a final diagnosis (p=0.121). A significant difference in diagnosis of a causative disease was found between patients who did or did not receive an ESR test (p=0.041). Of the 35 patients with an abnormal ESR value, 28 (80%) had causative disease identified.

CONCLUSIONS

Age may be a key factor in the differential diagnosis of FUO; the ESR test may be of value in the FUO evaluation process. These results may provide clinicians with insight into the management of FUO to allow adequate treatment according to the cause of the disease.

Miliary tuberculosis: Epidemiologicaland clinical analysis of large-case series from moderate to low tuberculosis endemic Country

The aim of this study was to determine the clinical features, and outcome of the patients with miliary tuberculosis (TB).We retrospectively evaluated 263 patients (142 male, 121 female, mean age: 44 years, range: 16-89 years) with miliary TB. Criteria for the diagnosis of miliary TB were at least one of the followings in the presence of clinical presentation suggestive of miliary TB such as prolonged fever, night sweats, anorexia, weight loss: radiologic criterion and pathological criterion and/or microbiological criterion; pathological criterion and/or microbiological criterion.The miliary pattern was seen in 88% of the patients. Predisposing factors were found in 41% of the patients. Most frequent clinical features and laboratory findings were fever (100%), fatigue (91%), anorexia (85%), weight loss (66%), hepatomegaly (20%), splenomegaly (19%), choroid tubercules (8%), anemia (86%), pancytopenia (12%), and accelerated erythrocyte sedimentation rate (89%). Tuberculin skin test was positive in 29% of cases. Fifty percent of the patients met the criteria for fever of unknown origin. Acid-fast bacilli were demonstrated in 41% of patients (81/195), and cultures for Mycobacterium tuberculosis were positive in 51% (148/292) of tested specimens (predominantly sputum, CSF, and bronchial lavage). Blood cultures were positive in 20% (19/97). Granulomas in tissue samples of liver, lung, and bone marrow were present in 100% (21/21), 95% (18/19), and 82% (23/28), respectively. A total of 223 patients (85%) were given a quadruple anti-TB treatment. Forty-four (17%) patients died within 1 year after diagnosis established. Age, serum albumin, presence of military pattern, presence of mental changes, and hemoglobin concentration were found as independent predictors of mortality. Fever resolved within first 21 days in the majority (90%) of the cases.Miliary infiltrates on chest X-ray should raise the possibility of miliary TB especially in countries where TB is endemic. Although biopsy of the lungs and liver may have higher yield rate of organ involvement histopathologicaly, less invasive procedures including a bone marrow biopsy and blood cultures should be preferred owing to low complication rates.

Adult-onset Still's disease-pathogenesis, clinical manifestations, and new treatment options

Adult-onset Still's disease (AOSD), a systemic inflammatory disorder, is often considered a part of the spectrum of the better-known systemic-onset juvenile idiopathic arthritis, with later age onset. The diagnosis is primarily clinical and necessitates the exclusion of a wide range of mimicking disorders. AOSD is a heterogeneous entity, usually presenting with high fever, arthralgia, skin rash, lymphadenopathy, and hepatosplenomegaly accompanied by systemic manifestations. The diagnosis is clinical and empirical, where patients are required to meet inclusion and exclusion criteria with negative immunoserological results. There are no clear-cut diagnostic radiological or laboratory signs. Complications of AOSD include transient pulmonary hypertension, macrophage activation syndrome, diffuse alveolar hemorrhage, thrombotic thrombocytopenic purpura and amyloidosis. Common laboratory abnormalities include neutrophilic leukocytosis, abnormal liver function tests, and elevated acute-phase reactants (ESR, CRP, ferritin). Treatment consists of anti-inflammatory medications. Non-steroidal anti-inflammatory drugs have limited efficacy, and corticosteroid therapy and disease-modifying anti-rheumatic drugs are usually required. Recent advances have revealed a pivotal role of proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1, IL-6, IL-8, and IL-18 in disease pathogenesis, giving rise to the development of novel targeted therapies aiming at optimal disease control. The review aims to summarize recent advances in pathophysiology and potential therapeutic strategies in AOSD.

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.

Diagnosing unexplained fever: can quick diagnosis units replace inpatient hospitalization?

BACKGROUND

Outpatient quick diagnosis units (QDUs) have become an increasingly recognized alternative to hospitalization for the diagnosis of a number of potentially serious diseases. No study has prospectively evaluated the usefulness of QDU for the diagnosis of unexplained fever.

MATERIALS AND METHODS

We prospectively assessed patients referred to QDU due to fever of uncertain nature (FUN), defined as a temperature > 38 °C during at least 1 week and no diagnosis after a previous evaluation. We also evaluated consecutive patients with FUN who were hospitalized during the same period. QDU and hospital costs were analysed by micro-costing techniques.

RESULTS

We evaluated 176 QDU patients and 168 controls. QDU patients were younger and required fewer investigations than controls. QDU patients had higher prevalence of viral infections (36% vs. 8%, P < 0·001) and lower prevalence of bacterial infections (6% vs. 46%, P < 0·001) and malignancies (2% vs. 14%, P < 0·001). While time-to-diagnosis of QDU patients was longer than length-of-stay of controls (25·82 vs.12·89 days, P < 0·001), 56% of QDU patients only required up to two visits. Cost per QDU patient was €644·59, while it was €4404·64 per hospitalized patient.

CONCLUSIONS

QDU patients with FUN were younger and had less serious diseases than controls including more viral and less bacterial infections and fewer malignancies. Mainly owing to untimely diagnostic reports, time-to-diagnosis was longer in QDU patients. Cost-savings in QDU were substantial. Using objective tools to evaluate the condition severity and general health status of FUN patients could help decide the most appropriate setting for their diagnostic study.

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.

Fever of unknown origin in a Mediterranean survey from a division of internal medicine: report of 91 cases during a 12-year-period (1991-2002)

Despite the availability of all advanced diagnostic tools, fever of unknown origin (FUO) remains a diagnostic challenge for physicians. The objective was to define, through a retrospective study, the categories of the diseases of Sicilian patients admitted at the Department of Clinical Medicine and Emerging Diseases, University of Palermo, Italy, for classical FUO. Using the registration system for patients admitted from 1991 to 2002, 508 charts of patients admitted because of fever were reviewed. Of these, only 91 patients fulfilled the criteria for classical FUO. The origin of FUO was diagnosed in 62 (68.1%) patients. Infection was the most common cause of FUO with 29 cases (31.8% of total of FUO), neoplasms accounted for 13 cases (14.2%), collagen vascular disease for 11 cases (12.0%), and miscellaneous for 9 cases (9.8%). Undiagnosed FUO were 29 (31.8%) and, of them, 22 cases were followed-up for 2 years. A definite diagnosis could be established only in 8 cases, 13 subjects completely recovered and 4 of them died. In the 73.4% of cases, the FUO have been the result of misleading factors in the diagnostic approaches as made by the physician. The results of our study are similar to those already reported by other authors in other populations, with infections as first, neoplasm as second, and collagen vascular diseases as third most important causes of FUO. In our study the prognosis for undiagnosed FUO cases was good, but a definite diagnosis could be established only in few cases. Therefore, further multicentric, prospective studies of good design are required.

The spectrum of diseases causing fever of unknown origin in Turkey: a multicenter study

OBJECTIVE

The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey.

METHODS

A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted.

RESULTS

The mean age of the patients was 42+/-17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37+/-23 days) was significantly longer compared to the patients with ID (25+/-12 days) (p=0.007). In patients with MD, the mean duration of fever (51+/-35 days) was longer compared to patients with ID (37+/-38 days) (p=0.052).

CONCLUSIONS

Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies.

Fever of Unknown Origin in Older Adults

Evaluation of elderly patients who have fever of unknown origin (FUO) requires a different perspective from that needed for young patients. Differential diagnosis often varies with age, and presentation of the disease frequently is nonspecific and symptoms difficult to interpret. Noninfectious diseases are the most frequent cause of FUO in the elderly and temporal arteritis the most frequent specific cause. Tuberculosis is the most common infectious disease associated with FUO in elderly patients. FUO often is associated with treatable conditions in the elderly. Therefore, intensive, accelerated evaluation is necessary, as the lack of physiologic reserve makes this population vulnerable to irreversible changes and functional deterioration.

Fever of unknown origin and cancer: a population-based study

BACKGROUND

Fever of unknown origin is associated with cancer, but the tumour types most commonly involved and the prognostic implications of this relation have not been studied. We aimed to assess the risk of cancer and survival after hospital admission for fever of unknown origin in a nationwide Danish follow-up study.

METHODS

We linked the Danish national registry of patients and the nationwide cancer registry, and assessed cancer risk for 43,205 patients discharged for the first time from Danish hospitals after admission for fever of unknown origin during 1977-97. We compared cancer frequency with that expected on the basis of cancer incidence in the general population, and survival of patients with cancer who had had fever of unknown origin with that of controls (ie, patients with cancer matched for cancer site, age at time of cancer diagnosis, and year of cancer diagnosis).

FINDINGS

Median follow-up was 6.3 years (IQR 2.7-12.3). During the first year of follow-up, 399 cancers were diagnosed in those who had had fever of unknown origin (standardised incidence ratio 2.3 [95% CI 2.1-2.5]). These individuals had an increased risk of developing cancer--in particular haematological malignant disease; sarcoma; and cancers of the liver, brain, kidney, colon, and pancreas. After 1 year of follow-up, individuals had an increased risk of developing haematological malignant disease and cancers of the liver, brain, and kidney. A slightly higher proportion of people diagnosed with cancer within 1 year of hospital discharge after fever of unknown origin had distant metastases compared with controls (101 [34%] of 294 vs 819 [28%] of 2907; prevalence ratio 1.2 [95% CI 1.0-1.4], and had worse survival than did controls (mortality rate ratio 1.4 [95% CI 1.2-1.6]).

INTERPRETATION

Hospital admission for fever of unknown origin is a marker of occult cancer and is associated with a poor outlook.

Fever of unknown origin-predictors of outcome. A prospective multicenter study on 164 patients

BACKGROUND: To date, the studies that have been done on fever of unknown origin have mostly been descriptive. Therefore, we know the etiogical spectrum and how it has changed since 1966 for many regions of the world. However, we do not know if there are clinical or laboratory predictors of severe outcome. Being able to estimate the severity of the disease early on would allow one to determine how intensive the diagnostic work-up should be. METHODS: A multicenter cohort study was carried out on 164 consecutive patients who met the classic, modified criteria of fever of unknown origin. The study lasted 2 years (1997-1998) and included a follow-up period of another 2 years. The main outcome measured was the final diagnosis established at the end of follow-up. RESULTS: When the white cell count was abnormal, the relative risk for a serious disease was 1.49 (CI: 1.15-1.94; p=0.004), when anemia was present, the relative risk was 1.55 (CI: 1.21-1.98; p=0.003), and for high alanine aminotransferase (ALAT), bilirubin, or lactate dehydrogenase (LDH), the relative risks were 1.57 (CI: 1.21-2.02; p=0.010), 1.57 (CI: 1.18-2.08; p=0.007), and 3.43 (CI: 1.81-6.48; p=0.0002), respectively. In multivariate analysis, the odds ratios for serious diseases were 2.7 (CI: 1.17-6.4; p=0.02) for abnormal white cell count, 2.8 (CI: 1.14-7.16; p=0.02) for anemia, 4.3 (CI: 1.6-11.5; p=0.003) for high serum bilirubin, and 5.3 (1.5-18.6; p=0.009) for high serum ALAT. CONCLUSIONS: In patients having a fever of unknown origin, anemia, abnormal white cell count, and high ALAT and bilirubin are independent predictors of severe outcome.

Fever of unknown origin in adults: 40 years on

A revision of the criteria of fever of unknown origin (FUO), established in 1961, is desirable because of important evolutions in medical practice and the emergence of new patient populations. The development of rapid laboratory tests and powerful diagnostic tools, such as ultrasonography, computed tomography and magnetic resonance imaging often makes hospitalization unnecessary and new categories of patients such as those with HIV infection, neutropenia, immunosuppression and nosocomial illness require an approach different from classical FUO. The more then 200 reported causes of FUO can be classified into four diagnostic categories; infections, tumours, noninfectious inflammatory diseases (NIID) and miscellaneous. A uniform classification system is highly wanted to allow comparison between different series. The reports of the 1990s show slight changes in the distribution of causes, namely less infections, less tumours, more NIID and more undiagnosed cases. A uniform diagnostic strategy cannot be determined. The initial investigation should be directed by potentially diagnostic clues revealed by extensive history, meticulous physical examination and a standard set of laboratory tests. 18Fluoro-deoxy-glucose-positron-emitted-tomography is a new valuable total body scintigraphy in the search for the site of origin of the fever. In view of the rather good long-term prognosis, a wait-and-see strategy may be more appropriate than a systematic staged approach. Elderly patients and patients with episodic fever represent two specific groups of classical FUO that require a distinct approach. HIV-associated, nosocomial and neutropenic FUO should be considered as separate clinical entities.

FEVER OF UNKNOWN ORIGIN

Forty six patients of fever of unknown origin in Service Hospitals who met the standard criteria were studied between 1989 and 1997. Infectious diseases contributed 21 patients (45.65%) of which 13 (28.26%) were diagnosed to have tuberculosis. Eight patients each (17.39%) of malignancies and collagen vascular diseases were seen, solid tumours were found in 5 patients. One (2.17%) patient had intrabdominal abscess. No diagnosis was made in 4 (8.69%) patients. The pattern and height of fever bore no correlation to aetiology. Serially repeated radiograph of chest was the most contributory investigation giving diagnostic information in 41.3%. Tissue/body fluid biopsy and cytology, serology, ultrasonography, computerised tomography and laparotomy were other useful investigations.

Fever of unknown origin

Fever of unknown origin (FUO) is defined as a temperature elevation of 101 degrees F (38.3 degrees C) or higher for 3 weeks or longer, the cause of which is not diagnosed after 1 week of intensive in-hospital investigation. This article discusses the causes, diagnosis, and treatment of FUOs.