Etiology and Resource Use of Fever of Unknown Origin in Hospitalized Children

Retrospective Analysis of Fever in Pediatric Age: Our Experience over the Last 5 Years

BACKGROUND

Fever is one of the most frequent symptoms highlighted during medical assistance. Due to this great impact, our study has the purpose of analyzing the demographic and laboratory characteristics of patients hospitalized in our center and identifying predictive markers to make the differential diagnosis between infectious and non-infectious fever.

METHODS

Our population included 220 children, collected from January 2017 to August 2022, hospitalized for continuous fever (4 days or more in duration with at least one temperature peak ≥37.5 °C) and excluded cases of discharge against medical advice and/or transfer to other operating units. Demographic (mean age at the time of admission, frequency of hospitalization, and mean days of hospitalization), laboratory, and instrumental variables were analyzed in order to find correlation with fever etiology.

RESULTS

Older age at the time of hospitalization, family history of periodic fever, fever lasting more than 8 days, and longer hospitalization are strongly associated with non-infectious fever, together with anemia, high platelet count, high CRP and ferritin, and hyponatremia at the time of admission. Paracetamol is the preferred antipyretic treatment. Echocardiogram has shown anomalies in patients with infectious fever, while ECG anomalies were detected in non-infectious fever.

CONCLUSIONS

Our data underline the importance of predictive markers, such as clinical and laboratory parameters, to differentiate infectious from non-infectious fevers, but further studies are necessary.

Fever of Unknown Origin

Fever of unknown origin in adolescents is a challenging disease state for which potential underlying etiology can include infectious, non-infectious inflammatory, and malignancy processes. Careful and thorough history (including exposure history), serial examination, and targeted laboratory and imaging testing is critical for these patients. In adolescents in which an etiology is discovered, infectious etiology remains the most prevalent, followed by non-infectious inflammatory diseases. In patients with non-diagnostic overall reassuring work up, the prognosis is typically self-limiting and favorable.

Update on Fever of Unknown Origin in Children: Focus on Etiologies and Clinical Approach

Fever of unknown origin (FUO) can be caused by four etiological categories of diseases. The most common cause of FUO in children is represented by infections, followed by inflammatory conditions and neoplastic causes; a decreasing quote remains still without diagnosis. Despite the fact that several diagnostic and therapeutic approaches have been proposed since the first definition of FUO, none of them has been fully validated in pediatric populations. A focused review of the patient's history and a thorough physical examination may offer helpful hints in suggesting a likely diagnosis. The diagnostic algorithm should proceed sequentially, and invasive testing should be performed only in select cases, possibly targeted by a diagnostic suspect. Pioneering serum biomarkers have been developed and validated; however, they are still far from becoming part of routine clinical practice. Novel noninvasive imaging techniques have shown promising diagnostic accuracy; however, their positioning in the diagnostic algorithm of pediatric FUO is still not clear. This narrative review aims to provide a synopsis of the existent literature on FUO in children, with its major causes and possible diagnostic workup, to help the clinician tackle the complex spectrum of pediatric FUO in everyday clinical practice.

Diagnosis of childhood febrile illness using a multi-class blood RNA molecular signature

BACKGROUND

Appropriate treatment and management of children presenting with fever depend on accurate and timely diagnosis, but current diagnostic tests lack sensitivity and specificity and are frequently too slow to inform initial treatment. As an alternative to pathogen detection, host gene expression signatures in blood have shown promise in discriminating several infectious and inflammatory diseases in a dichotomous manner. However, differential diagnosis requires simultaneous consideration of multiple diseases. Here, we show that diverse infectious and inflammatory diseases can be discriminated by the expression levels of a single panel of genes in blood.

METHODS

A multi-class supervised machine-learning approach, incorporating clinical consequence of misdiagnosis as a "cost" weighting, was applied to a whole-blood transcriptomic microarray dataset, incorporating 12 publicly available datasets, including 1,212 children with 18 infectious or inflammatory diseases. The transcriptional panel identified was further validated in a new RNA sequencing dataset comprising 411 febrile children.

FINDINGS

We identified 161 transcripts that classified patients into 18 disease categories, reflecting individual causative pathogen and specific disease, as well as reliable prediction of broad classes comprising bacterial infection, viral infection, malaria, tuberculosis, or inflammatory disease. The transcriptional panel was validated in an independent cohort and benchmarked against existing dichotomous RNA signatures.

CONCLUSIONS

Our data suggest that classification of febrile illness can be achieved with a single blood sample and opens the way for a new approach for clinical diagnosis.

FUNDING

European Union's Seventh Framework no. 279185; Horizon2020 no. 668303 PERFORM; Wellcome Trust (206508/Z/17/Z); Medical Research Foundation (MRF-160-0008-ELP-KAFO-C0801); NIHR Imperial BRC.

Evaluation of CRP as a marker for bacterial infection and malaria in febrile children at the Douala Gyneco-Obstetric and Pediatric Hospital

BACKGROUND

C reactive protein (CRP), a marker for the presence of inflammation, has been extensively studied for distinguishing bacterial from non-bacterial infection in febrile patients, but its role in excluding malaria in the febrile child has not been thoroughly evaluated.

METHOD

This was a cross-sectional study at the Douala Gyneco-Obstetric and Pediatric Hospital which included all patients between the ages of one month and 16 years presenting with fever. Consenting patients received complete clinical examinations, then venous blood samples were collected and tested for CRP values, bacterial infection and malaria.

RESULTS

Samples of 220 children were analyzed. 142/220 had viral infections, 50/220 had malaria and 49/220 had bacterial infections. 7/220 had both malaria and bacterial infection. There was no significant difference between mean CRP values in malaria and bacterial infection (p = 1), but CRP means were significantly higher in malaria/bacterial infection than in viral infection (p<0.0001). Area Under the Receiver Operating Characteristics Curve (AUROC) values were 0.94 for malaria and 0.86 for bacterial infection, with a calculated cut-off of 23.6mg/L for malaria and 36.2mg/L for bacterial infection. At these cut-offs, CRP had a Positive Predictive Value (PPV) of 68.75% and 85.00% for malaria and bacterial infection respectively, with a Negative Predictive Value (NPV) of 94.74% and 89.05% respectively.

CONCLUSION

CRP can effectively exclude malaria and bacterial infection in febrile children in low-resource settings without the need for additional tests.

Early application of metagenomics next-generation sequencing may significantly reduce unnecessary consumption of antibiotics in patients with fever of unknown origin

BACKGROUND

Metagenomic next-generation sequencing (mNGS) is a novel nucleic acid method for the detection of unknown and difficult pathogenic microorganisms, and its application in the etiological diagnosis of fever of unknown origin (FUO) is less reported. We aimed to comprehensively assess the value of mNGS in the etiologic diagnosis of FUO by the pathogen spectrum and diagnostic performance, and to investigate whether it is different in the time to diagnosis, length of hospitalization, antibiotic consumption and cost between FUO patients with and without early application of mNGS.

METHODS

A total of 149 FUO inpatients underwent both mNGS and routine pathogen detection was retrospectively analyzed. The diagnostic performance of mNGS, culture and CMTs for the final clinical diagnosis was evaluated by using sensitivity, specificity, positive predictive value, negative predictive value and total conforming rate. Patients were furtherly divided into two groups: the earlier mNGS detection group (sampling time: 0 to 3 days of the admission) and the later mNGS detection group (sampling time: after 3 days of the admission). The length of hospital stay, time spent on diagnosis, cost and consumption of antibiotics were compared between the two groups.

RESULTS

Compared with the conventional microbiological methods, mNGS detected much more species and had the higher negative predictive (67.6%) and total conforming rate (65.1%). Patients with mNGS sampled earlier had a significantly shorter time to diagnosis (6.05+/-6.23 vs. 10.5+/-6.4 days, P < 0.001) and days of hospital stay (13.7+/-20.0 vs. 30.3 +/-26.9, P < 0.001), as well as a significantly less consumption (13.3+/-7.8 vs. 19.5+/-8.0, P < 0.001) and cost (4543+/-7326 vs. 9873 +/- 9958 China Yuan [CNY], P = 0.001) of antibiotics compared with the patients sampled later.

CONCLUSIONS

mNGS could significantly improve the detected pathogen spectrum, clinical conforming rate of pathogens while having good negative predictive value for ruling out infections. Early mNGS detection may shorten the diagnosis time and hospitalization days and reduce unnecessary consumption of antibiotics.

Antibiotic Use and Respiratory Viral PCR Testing Among Pediatric Patients With Nosocomial Fever

Objective Pediatric patients admitted to the hospital often develop fevers during their inpatient stay, and many children are empirically started on antibiotics. The utility of respiratory viral panel (RVP) polymerase chain reaction (PCR) testing in the evaluation of nosocomial fevers in admitted patients is unclear. We sought to evaluate whether RVP testing is associated with the use of antibiotics among inpatient pediatric patients. Patients and methods We conducted a retrospective chart review of children admitted from November 2015 to June 2018. We included all patients who developed fever 48 hours or more after admission to the hospital and who were not already receiving treatment for a presumed infection (on antibiotics). Results Among 671 patients, there were 833 inpatient febrile episodes. The mean age of children was 6.3 years old, and 57.1% were boys. Out of 99 RVP samples analyzed, 22 were positive (22.2%). Antibiotics were started in 27.8% while 33.5% of patients were already on antibiotics. On multivariate logistic regression, having an RVP sent was significantly associated with increased initiation of antibiotics (aOR 95% CI 1.18-14.18, p=0.03). Furthermore, those with a positive RVP had a shorter course of antibiotics compared to those with a negative RVP (mean 6.8 vs 11.3 days, p=0.019). Conclusions Children with positive RVP had decreased antibiotic exposure compared to those with negative RVP results. RVP testing may be used to promote antibiotic stewardship among hospitalized children.

Etiology and clinical characteristics of pediatric acute fever among hospitalized children in an endemic malaria transmission area of Cameroon in Central Africa

Acute fever in the majority of children in resource-limited countries is attributable to malaria and often treated without laboratory evidence. The aim of the study was to characterize acute pediatric infectious fevers (APIF) in the pediatric department of the Douala Laquintinie Hospital. A cross-sectional study was conducted among children aged 2 months to 15 years who were admitted with an acute fever (anal temperature ≥ 37.5°C less than 5 days in infants and 7 days in adolescents). 200 children were included and followed up during their hospitalization. The mean age was 3.7 (IQ25-75: 1-4.6) years. More than 3 out of 5 patients (62.5%) came from another health facility and anemia accounted for 29% of the reasons for consultation associated with fever. The main symptoms were vomiting (28%), cough (26%), convulsions (21%) and diarrhea (20%). Skin-mucosal pallor (43.0%) and hepatosplenomegaly (26.0%) were the most common physical signs encountered. Among febrile children, 116/200 (58%) were infected with at least 1 pathogen, and 1/200 (0.5%) had a fever of unknown etiology. Malaria (53% vs 80.5% presumptive) associated with anemia (95.3% of cases) was the most common pathology associated with APIF, followed by pneumonia (19.5%), meningitis (11.5%) and urinary tract infections (10% vs 54.5% presumptive). Malaria was over-diagnosed on admission and over-treated as well as urinary tract infection. A better understanding of common pathogens carriage, a better capacity for improved diagnosis and a better applied clinical algorithm for febrile illnesses in children are needed.

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.

[Fever of unknown origin]

Fieber unklarer Genese wird diagnostiziert, wenn das Fieber (meist definiert als Körpertemperatur ≥ 38,3 °C, gemessen rektal oder am Trommelfell) länger dauert als erwartet, also nach 5 bis 10 Tagen. Die Ursachensuche kann sich schwierig gestalten und bedarf der erhöhten Aufmerksamkeit des erfahrenen Allgemeinpädiaters in Zusammenarbeit mit pädiatrischen Infektiologen, Rheumatologen und Onkologen, der Pflege, Radiologen und anderen. In etwa der Hälfte der Fälle findet sich am Ende doch eine Infektion; weitere Ursachen sind primär entzündliche oder onkologische sowie nichtentzündliche Erkrankungen. Einzelne Ursachen mit der Gefahr des schweren Verlaufs müssen sofort behandelt werden. Ansonsten gibt es ein klares Primat der Diagnostik, die klug geplant und sowohl zielstrebig als auch breit durchgeführt wird. Anamnese, physikalischer Befund, Laborbestimmungen, apparative Diagnostik, bildgebende und histologische Untersuchungen können zur Diagnose beitragen. Die Eltern sind durch die Ungewissheit hindurchzuführen, und dem Kind sollte die Situation möglichst erleichtert werden. Es kommen auch Spontanheilungen vor. Die probatorische Gabe von Antibiotika führt selten zur Besserung. Nach weitgehendem Ausschluss von Infektion, Malignom und zunehmendem Leiden unter dem Fieber selbst, können bei hoher Entzündungsaktivität, unter dem Verdacht auf einen hyperergen Status und nach ausführlicher Aufklärung Glukokortikoide angesetzt werden. Das Management des Fiebers unklarer Genese ist eine der großen Herausforderungen der Pädiatrie.

Role of FDG-PET/CT in children with fever of unknown origin

PURPOSE

To determine the role of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET)/computed tomography (CT) in children with fever of unknown origin (FUO).

METHODS

This retrospective single-center study included 110 children (0-18 years) with FUO who underwent FDG-PET/CT between 2010 and 2019. The diagnostic value of FDG-PET/CT for identifying cause of fever was calculated, treatment modifications after FDG-PET/CT were assessed, and logistic regression analyses were performed to identify clinical and biochemical factors associated with FDG-PET/CT outcome.

RESULTS

In 53 out of 110 patients (48%), FDG-PET/CT identified a (true positive) cause of fever. Endocarditis (11%), systemic juvenile idiopathic arthritis (5%), and inflammatory bowel disorder (5%) were the most common causes of FUO. In 42 patients (38%), no cause of fever was found on FDG-PET/CT. In 58 out of 110 patients (53%), treatment modifications were made after FDG-PET/CT. FDG-PET/CT achieved a sensitivity of 85.5%, specificity of 79.2%, positive predictive value of 84.1%, and negative predictive value of 80.9%. On multivariate logistic regression, C-reactive protein was positively associated with finding a true positive focus of fever on FDG-PET/CT (OR = 1.01 (95% CI 1.00-1.02) per mg/L increase in CRP), while leukocyte count was negatively associated with finding a true positive focus of fever (OR = 0.91 (95% CI 0.85-0.97) per 109 leukocytes/L increase).

CONCLUSION

FDG-PET/CT is a valuable diagnostic tool in the evaluation of children with FUO, since it may detect a true underlying cause in almost half (48%) of all cases where none was found otherwise. It allows full-body evaluation in patients without disease-specific symptoms on one examination. CRP and leukocyte count were significantly associated with FDG-PET/CT results, which may contribute to a priori assessment on the outcome of FDG-PET/CT. Future research could be aimed at evaluating more patient-specific factors to prospectively estimate the added value of FDG-PET/CT in children with FUO.

Fever of unknown origin: a retrospective review of pediatric patients from an urban, tertiary care center in Washington, DC

BACKGROUND

Fever of unknown origin (FUO) continues to challenge clinicians to determine an etiology and the need for treatment. This study explored the most common etiologies, characteristics, and average cost of hospitalization for FUO in a pediatric population at an urban, tertiary care hospital in Washington, DC.

METHODS

Records from patients admitted to Children's National Health System between September 2008 and April 2014 with an admission ICD-9 code for fever (780.6) were reviewed. The charts of patients 2-18 years of age with no underlying diagnosis and a temperature greater than 38.3 ºC for 7 days or more at time of hospitalization were included. Final diagnoses, features of admission, and total hospital charges were abstracted.

RESULTS

110 patients qualified for this study. The majority of patients (n = 42, 38.2%) were discharged without a diagnosis. This was followed closely by infection, accounting for 37.2% (n = 41) of patients. Rheumatologic disease was next (n = 16, 14.5%), followed by miscellaneous (n = 6, 5.4%) and oncologic diagnoses (n = 5, 4.5%). The average cost of hospitalization was 40,295 US dollars.

CONCLUSIONS

This study aligns with some of the most recent publications which report undiagnosed cases as the most common outcome in patients hospitalized with FUO. Understanding that, often no diagnosis is found may reassure patients, families, and clinicians. The cost associated with hospitalization for FUO may cause clinicians to reconsider inpatient admission for diagnostic work-up of fever, particularly given the evidence demonstrating that many patients are discharged without a diagnosis.

Comparison of initial and final diagnoses in children with acute febrile illness: A retrospective, descriptive study: Initial and final diagnoses in children with acute fever

BACKGROUND

This study aimed to elucidate the etiologies and diagnostic errors of early-phase pediatric fever without an obvious cause.

METHODS

This single-center, retrospective, descriptive study included 1334 febrile children hospitalized at Beppu Medical Center in Japan between 2014 and 2018. Eligibility criteria were age ≤12 years, axillary temperature ≥38.0°C, and fever duration ≤7 days at admission. Initial diagnoses on the day of admission and final diagnoses at defervescence were divided into initial fever with identified source (FIS) and initial fever without source (FWS) and final FIS and final FWS, respectively. The etiology of initial FWS and diagnostic discordance between initial FIS and final FIS were investigated.

RESULTS

Of the 1334 participants, 94 (7.0%) were diagnosed with initial FWS. Among patients with initial FWS, final diagnoses were confirmed in 40 (43%), including Kawasaki disease in 17, urinary tract infection in 5, bacteremia in 4, exanthem subitum in 3, and the others in 11. Among the 1275 patients diagnosed with final FIS, diagnostic discordances between initial and final diagnoses were observed in 131 patients (10%). The multiple logistic regression analysis identified increased serum C-reactive protein value at admission (odds ratio [OR]: 1.09; 95% confidence interval [CI]: 1.06-1.13), exanthem subitum (OR: 409; 95% CI: 119-1399), and Kawasaki disease (OR: 14.3; 95% CI: 8.7-23.3) as independent risk factors for diagnostic discordance.

CONCLUSION

Exanthem subitum and Kawasaki disease may be undiagnosed or misdiagnosed in febrile children with fever duration ≤7 days.

The impact of global budgeting in Taiwan on inpatients with unexplained fever

Unexplained fever is one of the most common and difficult diagnostic problems faced daily by clinicians. This study evaluated the differences in health service utilization, health care expenditures, and quality of care provided to patients with unexplained fever before and after global budget (GB) implementation in Taiwan.The National Health Insurance Research Database was used for analyzing the health care expenditures and quality of care before and after implementation of the GB system. Patients diagnosed as having unexplained fever during 2000-2001 were recruited; their 2000-2001 and 2004-2005 data were considered baseline and postintervention data, respectively.Data of 259 patients with unexplained fever were analyzed. The mean lengths of stay (LOSs) before and after GB system implementation were 4.22 ± 0.35 days and 5.29 ± 0.70 days, respectively. The mean costs of different health care expenditures before and after implementation of the GB system were as follows: the mean diagnostic, drug, therapy, and total costs increased respectively from New Taiwan Dollar (NT$) 1440.05 ± NT$97.43, NT$3249.90 ± NT$1108.27, NT$421.03 ± NT$100.03, and NT$13,866.77 ± NT$2,114.95 before GB system implementation to NT$2224.34 ± NT$238.36, NT$4272.31 ± NT$1466.90, NT$2217.03 ± NT$672.20, and NT$22,856.41 ± NT$4,196.28 after implementation. The mean rates of revisiting the emergency department within 3 days and readmission within 14 days increased respectively from 10.5% ± 2.7% and 8.3% ± 2.4% before implementation to 6.3% ± 2.2% and 4.0% ± 1.7% after implementation.GB significantly increased LOS and incremental total costs for patients with unexplained fever; but improved the quality of care.