Nuclear Medicine Imaging Tools in Fever of Unknown Origin (FUO): Time for a Revisit and Appropriate Use Criteria

Fever of unknown origin (FUO) is a clinical conundrum for patients and clinicians alike and imaging studies are often performed as part of the diagnostic workup of these patients. Recently, the Society of Nuclear Medicine and Molecular Imaging (SNMMI) convened and approved a guideline on the use of nuclear medicine tools for FUO. The guidelines support the use of 2-18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) in adults and children with FUO. 18F-FDG PET/CT allows the detection and localization of foci of hypermetabolic lesions with high sensitivity, based on 18F-FDG uptake in glycolytically active cells that may represent inflammation, infection, or neoplasia. Clinicians should consider and insurers should cover 18F-FDG PET/CT when evaluating patients with FUO, particularly when other clinical clues and preliminary studies are unrevealing.

Comparison of diagnostic spectrum between inflammation of unknown origin and fever of unknown origin: A systematic review and meta-analysis

BACKGROUND

Patients with inflammation of unknown origin (IUO) and fever of unknown origin (FUO) are commonly considered a single population. Differences in underlying causes between both groups may steer the diagnostic work-up.

METHODS

PubMed, Embase, Web of Science, and ClinicalTrials.gov were searched from July 2009 through December 2023. Studies including both FUO and IUO patients with a sample size of ≥20 were considered. The primary outcome was the difference in the rate of patients affected by predefined diagnostic categories according to meeting FUO or IUO criteria. Data were pooled using random-effects models.

RESULTS

A total of 8 studies met criteria for inclusion, with a total of 1452 patients (466 with IUO and 986 with FUO). The median rate of IUO patients among the included studies was 32 % (range 25-39 %). Patients with IUO had a lower likelihood of infection (OR 0.59 [95 % CI; 0.36-0.95]; I2 0 %). There were no significant differences in the rate of noninfectious inflammatory disorders, malignancies, miscellaneous disorders, or remaining undiagnosed. Comparison of diagnostic subgroups revealed that IUO patients were less likely to have systemic autoinflammatory disorders (OR 0.17 [95 % CI, 0.05-0.58]; I2 42 %) and more likely to have vasculitis (OR 2.04 [95 % CI, 1.23-3.38]; I2 21 %) and rheumatoid arthritis or spondylarthritis (OR 3.52 [95 % CI, 1.16-10.69]; I2 0 %).

CONCLUSION

Based on our findings, there is little reason to assume that FUO and IUO patients would benefit from a different initial diagnostic approach.

Development of a Consensus-Based List of Potential Quality Indicators for Fever and Inflammation of Unknown Origin

With a growing emphasis on value-based reimbursement, developing quality indicators for infectious diseases has gained attention. Quality indicators for fever of unknown origin and inflammation of unknown origin are lacking. An assembled group of international experts developed 12 quality measures for these conditions, which could be validated with additional study.

Molecular Imaging of Infections: Emerging Techniques for Pathogen-Specific Diagnosis and Guided Therapy

Evaluation of patients that may be infected is challenging. Imaging to identify or localize a site of infection is often limited because of the nonspecific nature of the findings on conventional imaging modalities. Available imaging methods lack the ability to determine if antibiotics are reaching the site of infection and are not optimized to follow response to therapy. Positron emission tomography (PET) is a method by which radiolabeled molecules can be used to detect metabolic perturbations or levels of expression of specific targets. The most common PET agent is the glucose analog 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG). 18F-FDG has some applicability to localizing a site of infection, but its lack of specificity limits its usefulness. There is a need for the development of pathogen-specific PET radiotracers to address the imaging shortcomings noted above. Preclinical and clinical progress has been made, but significant challenges remain.

#AMRrounds: a systematic educational approach for navigating bench to bedside antimicrobial resistance

Antimicrobial resistance (AMR) continues to serve as a major global health crisis. Clinicians practising in this modern era are faced with ongoing challenges in the therapeutic management of patients suffering from antimicrobial-resistant infections. A strong educational understanding and synergistic application of clinical microbiology, infectious disease and pharmacological concepts can assist the adventuring clinician in the navigation of such cases. Important items include mobilizing laboratory testing for pathogen identification and susceptibility data, harnessing an understanding of intrinsic pathogen resistance, acknowledging epidemiological resistance trends, recognizing acquired AMR mechanisms, and consolidating these considerations when constructing an ideal pharmacological plan. In this article, we outline a novel framework by which to systematically approach clinical AMR, encourage AMR-related education and optimize therapeutic decision-making in AMR-related illnesses.

Higher diagnostic yield of 18F-FDG PET in inflammation of unknown origin compared to fever of unknown origin

OBJECTIVE

18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is an important imaging technique in the workup of fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Studies comparing the diagnostic yield of 18F-FDG PET between both entities are lacking.

METHODS

Retrospective analysis of FUO/IUO patients who underwent 18F-FDG PET between 2000 and 2019 in the University Hospitals of Leuven (Belgium). 18F-FDG PET images were assessed for accuracy and contribution towards the final diagnosis. Logistic regression was performed to evaluate the association between meeting FUO or IUO criteria and diagnostic contribution of 18F-FDG PET with and without adjustment for confounders.

RESULTS

Out of 604 patients, 439 (73%, mean age 56 years, 43% female) underwent 18F-FDG PET imaging, including 349 (79%) classified as FUO and 90 (21%) as IUO. Noninfectious inflammatory disorders were significantly more frequent in the IUO group (37% versus 25%; P = 0.03). 18F-FDG PET imaging had a sensitivity of 93% (89-96%), a specificity of 35% (29-42%), and made a positive contribution to the final diagnosis in 25% (21-29%) of cases. IUO was significantly associated with contributive 18F-FDG PET imaging compared to FUO (aOR 2.21 [95% CI 1.31-3.72]; P = 0.003). Among those with contributive 18F-FDG PET imaging, giant cell arteritis (IUO 25% versus FUO 12%) and polymyalgia rheumatica (IUO 17% versus FUO 1%) were numerically more frequent in the IUO group.

CONCLUSION

The diagnostic contribution of 18F-FDG PET was higher among those with IUO, most likely due to differences in diagnostic spectrum.

Investigator-Determined Categories for Fever of Unknown Origin (FUO) Compared With International Classification of Diseases-10 Classification of Illness: A Systematic Review and Meta-analysis With a Proposal for Revised FUO Classification

Background

Classifying fever of unknown origin (FUO) into categorical etiologies (ie, infections, noninfectious inflammatory, oncologic, miscellaneous, and undiagnosed disorders) remains unstandardized and subject to discrepancies. As some disease classifications change, a systematic review of studies would help physicians anticipate the frequency of illness types they may encounter that could influence care.

Methods

We systematically reviewed prospective FUO studies published across the Medline (PubMed), Embase, Scopus, and Web of Science databases from January 1, 1997, to July 31, 2022. We performed a meta-analysis to estimate associated pooled proportions between the investigator-determined choice of disease category and those determined by the International Classification of Diseases, 10th edition (ICD-10), methodology.

Results

The proportion of patients with a difference between the investigator and ICD-10-adjusted noninfectious inflammatory disorder category was 1.2% (95% CI, 0.005-0.021; P < .001), and the proportion was similar for the miscellaneous category at 1.5% (95% CI, 0.007-0.025; P < .001). The miscellaneous and noninfectious inflammatory disorders categories demonstrated significant across-study heterogeneity in the proportions of patients changing categories, with 52.7% (P = .007) and 51.0% (P = .010) I² , respectively.

Conclusions

Adjusting FUO-associated diagnoses by ICD-10 methodology was associated with a statistically significant risk of over- or underestimation of disease category frequency approximation when using a 5 FUO category system. An FUO diagnostic classification system that better reflects mechanistic understanding would assist future research and enhance comparability across heterogenous populations and different geographic regions. We propose an updated FUO classification scheme that streamlines categorizations, aligns with the current understanding of disease mechanisms, and should facilitate empirical decisions, if necessary.

Etiological spectrum and outcome of fever and inflammation of unknown origin. Does symptom duration matter?

OBJECTIVE

Evidence suggests that the symptom duration may affect the occurrence of certain fever (FUO) and inflammation (IUO) of unknown origin associated conditions. It is unclear if this could potentially guide diagnostic evaluations. We examined the association between symptom duration and diagnostic and prognostic outcomes in FUO/IUO.

METHODS

We retrospectively analyzed a cohort of adult patients meeting criteria for FUO/IUO from a tertiary care center in Belgium between 2000 and 2019. The association between symptom duration and outcomes of interest were estimated by Cox proportional hazards models.

RESULTS

Among 602 patients who met criteria for FUO/IUO (mean age 54 years, 43% female), 132 (22%) and 68 (11%) had symptoms for 3-12 months and >12 months, respectively. There were no significant differences in diagnosis or all-cause mortality between a symptom duration of <3 months and 3-12 months. In contrast, those who had a symptom duration of >12 months were less likely to receive a final diagnosis (aHR 0.42, 95% CI 0.30-0.60), in particular a diagnosis of infectious disorders (aHR 0.29, 95% CI 0.12-0.74), malignancies (aHR 0.11, 95% CI 0.03-0.46), and miscellaneous conditions (aHR 0.22, 95% CI 0.07-0.71), but no significant differences were seen in noninfectious inflammatory disorders (aHR 0.74, 95% CI 0.48-1.15) or all-cause mortality (aHR 0.55, 95% CI 0.19-1.54).

CONCLUSIONS

The symptom duration may be used to guide the diagnostic workup among patients with FUO and IUO, in particular those with longstanding symptoms.

Geographic Upon Noninfectious Diseases Accounting for Fever of Unknown Origin (FUO): A Systematic Review and Meta-analysis

Background

Diagnostic outcomes for fever of unknown origin (FUO) remain with notable numbers of undiagnosed cases. A recent systemic review and meta-analysis of studies reported geographic variation in FUO-related infectious diseases. Whether geography influences types of FUO noninfectious diagnoses deserves examination.

Methods

Medline (PubMed), Embase, Scopus, and Web of Science databases were searched systematically using medical subject headings published from January 1, 1997, to March 31, 2021. Prospective clinical studies investigating participants meeting adult FUO defining criteria were selected if they assessed final diagnoses. Meta-analyses were based on the random-effects model according to World Health Organization (WHO) geographical regions.

Results

Nineteen studies with significant heterogeneity were analyzed, totaling 2,667 participants. Noninfectious inflammatory disorders had a pooled estimate at 20.0% (95%CI: 17.0-23.0%). Undiagnosed illness had a pooled estimate of 20.0% (95%CI: 14.0-26.0%). The pooled estimate for cancer was 15.0% (95%CI: 12.0-18.0%). Miscellaneous conditions had a pooled estimate of 6.0% (95%CI: 4.0-8.0%). Noninfectious inflammatory disorders and miscellaneous conditions were most prevalent in the Western Pacific region with a 27.0% pooled estimate (95%CI: 20.0-34.0%) and 9.0% (95%CI: 7.0-11.0%), respectively. The highest pooled estimated for cancer was in the Eastern Mediterranean region at 25.0% (95%CI: 18.0-32.0%). Adult-onset Still’s disease (114 [58.5%]), systemic lupus (52 [26.7%]), and giant-cell arteritis (40 [68.9%]) predominated among the noninfectious inflammatory group. Lymphoma (164 [70.1%]) was the most common diagnosis in the cancer group.

Conclusions

In this systematic review and meta-analysis, noninfectious disease diagnostic outcomes varied among WHO-defined geographies. Evaluation of FUO should consider local variations in disease prevalence.

Prospective Studies Comparing Structured vs Nonstructured Diagnostic Protocol Evaluations Among Patients With Fever of Unknown Origin: A Systematic Review and Meta-analysis

Importance

Patients meeting the criteria for fever of unknown origin (FUO) can be evaluated with structured or nonstructured approaches, but the optimal diagnostic method is unresolved.

Objective

To analyze differences in diagnostic outcomes among patients undergoing structured or nonstructured diagnostic methods applied to prospective clinical studies.

Data Sources

PubMed, Embase, Scopus, and Web of Science databases with librarian-generated query strings for FUO, PUO, fever or pyrexia of unknown origin, clinical trial, and prospective studies identified from January 1, 1997, to March 31, 2021.

Study Selection

Prospective studies meeting any adult FUO definition were included. Articles were excluded if patients did not precisely fit any existing adult FUO definition or studies were not classified as prospective.

Data Extraction and Synthesis

Abstracted data included years of publication and study period, country, setting (eg, university vs community hospital), defining criteria and category outcome, structured or nonstructured diagnostic protocol evaluation, sex, temperature threshold and measurement, duration of fever and hospitalization before final diagnoses, and contribution of potential diagnostic clues, biochemical and immunological serologic studies, microbiology cultures, histologic analysis, and imaging studies. Structured protocols compared with nonstructured diagnostic methods were analyzed using regression models.

Main Outcomes and Measures

Overall diagnostic yield was the primary outcome.

Results

Among the 19 prospective trials with 2627 unique patients included in the analysis (range of patient ages, 10-94 years; 21.0%-55.3% female), diagnoses among FUO series varied across and within World Health Organization (WHO) geographic regions. Use of a structured diagnostic protocol was not significantly associated with higher odds of yielding a diagnosis compared with nonstructured protocols in aggregate (odds ratio [OR], 0.98; 95% CI, 0.65-1.49) or between Western Europe (Belgium, France, the Netherlands, and Spain) (OR, 0.95; 95% CI, 0.49-1.86) and Eastern Europe (Turkey and Romania) (OR, 0.83; 95% CI, 0.41-1.69). Despite the limited number of studies in some regions, analyses based on the 6 WHO geographic areas found differences in the diagnostic yield. Western European studies had the lowest percentage of achieving a diagnosis. Southeast Asia led with infections at 49.0%. Noninfectious inflammatory conditions were most prevalent in the Western Pacific region (34.0%), whereas the Eastern Mediterranean region had the highest proportion of oncologic explanations (24.0%).

Conclusions and Relevance

In this systematic review and meta-analysis, diagnostic yield varied among WHO regions. Available evidence from prospective studies did not support that structured diagnostic protocols had a significantly better rate of achieving a diagnosis than nonstructured protocols. Clinicians worldwide should incorporate geographical disease prevalence in their evaluation of patients with FUO.

Large Scale SARS-CoV-2 Molecular Testing and Genomic Surveillance Reveal Prolonged Infections, Protracted RNA shedding, and Viral Reinfections

Large-scale SARS-CoV-2 molecular testing coupled with whole genome sequencing in the diagnostic laboratories is instrumental for real-time genomic surveillance. The extensive genomic, laboratory, and clinical data provide a valuable resource for understanding cases of reinfection versus prolonged RNA shedding and protracted infections. In this study, data from a total of 22,292 clinical specimens, positive by SARS-CoV-2 molecular diagnosis at Johns Hopkins clinical virology laboratory between March 11th 2020 to September 23rd 2021, were used to identify patients with two or more positive results. A total of 3,650 samples collected from 1,529 patients who had between 2 and 20 positive results were identified in a time frame that extended up to 403 days from the first positive. Cycle threshold values (Ct) were available for 1,622 samples, the median of which was over 30 by 11 days after the first positive. Extended recovery of infectious virus on cell culture was notable for up to 70 days after the first positive in immunocompromised patients. Whole genome sequencing data generated as a part of our SARS-CoV-2 genomic surveillance was available for 1,027 samples from patients that had multiple positive tests. Positive samples collected more than 10 days after initial positive with high quality sequences (coverage >90% and mean depth >100), were more likely to be from unvaccinated, or immunosuppressed patients. Reinfections with viral variants of concern were found in 3 patients more than 130 days from prior infections with a different viral clade. In 75 patients that had 2 or more high quality sequences, the acquisition of more substitutions or deletions was associated with lack of vaccination and longer time between the recovered viruses. Our study highlights the value of integrating genomic, laboratory, and clinical data for understanding the biology of SARS-CoV-2 as well as for setting a precedent for future epidemics and pandemics.

Geographic Variation of Infectious Disease Diagnoses Among Patients with Fever of Unknown Origin (FUO) – A Systematic Review and Meta-analysis

Background

Fever of unknown origin (FUO) investigations yield a substantial number of patients with infectious diseases. This systematic review and meta-analysis aimed to quantify more common FUO infectious diseases etiologies and to underscore geographic variation.

Methods

Four databases (PubMed, Embase, Scopus, and Web of Science) were searched for prospective studies reporting FUO rates among adult patients from 1 January 1997 to 31 March 2021. The pooled proportion for infectious diseases etiology was estimated using the random-effects meta-analysis model.

Results

Nineteen prospective studies were included with 2667 total cases. No studies were available for Africa or the Americas. Overall, 37.0% (95.0% confidence interval [CI], 30.0%–44.0%) of FUO patients had an infectious disease etiology. Infections were more likely from Southeastern Asia (pooled proportion, 0.49 [95% CI, .43–.55]) than from Europe (pooled proportion, 0.31 [95% CI, .22–.41]). Among specifically reported infectious diseases (n = 832), Mycobacterium tuberculosis complex predominated across all geographic regions (n = 285 [34.3%]), followed by brucellosis (n = 81 [9.7%]), endocarditis (n = 62 [7.5%]), abscesses (n = 61 [7.3%]), herpesvirus (eg, cytomegalovirus and Epstein-Barr virus) infections (n = 60 [7.2%]), pneumonia (n = 54 [6.5%]), urinary tract infections (n = 54 [6.5%]), and enteric fever (n = 40 [4.8%]).

Conclusions

FUO patients from Southeastern Asia were more likely to have an infectious diseases etiology when compared to other regions. The predominant factor for this finding appears to be differences in disease prevalence among various geographical locations or other factors such as access to timely care and diagnosis. Noting epidemiological disease factors in FUO investigations could improve diagnostic yields and clinical outcomes.

Fever of Unknown Origin (FUO) - A Call for New Research Standards and Updated Clinical Management

Prolonged fever of 38.3°C or higher for at least 3 weeks' duration has been termed fever of unknown origin if unexplained after preliminary investigations. Initially codified in 1961, classification with subgroups was revised in 1991. Additional changes to the definition were proposed in 1997, recommending a set of standardized initial investigations. Advances in diagnosis and management and diagnostic testing over the last 3 decades have prompted a needed update to the definition and approaches. While a 3-week fever duration remains part of the criteria, a lower temperature threshold of 38°C and revised minimum testing criteria will assist clinicians and their patients, setting a solid foundation for future research.

Should Therapeutic Drug Monitoring Based on the Vancomycin Area Under the Concentration-Time Curve Be Standard for Serious Methicillin-Resistant Staphylococcus aureus Infections?-No

In this counterpoint we critically appraise the evidence supporting therapeutic drug monitoring based on the vancomycin 24-hour area under the concentration-time curve (AUC24) for serious methicillin-resistant Staphylococcus aureus infections. We reveal methodologically weaknesses and inconsistencies in the data and suggest that, in the absence of clear and convincing evidence of benefit compared with modestly reducing trough targets, alternative strategies are more likely to result in superior safety and efficacy. These include focusing on fundamental antibiotic stewardship to limit vancomycin exposure overall, achieving earlier and more complete source control, and establishing alternative therapeutic options to vancomycin. Implementation of AUC24-based therapeutic drug monitoring will take resources away from these more promising, alternative solutions.

Imaging a Fever-Redefining the Role of 2-deoxy-2-[18F]Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography in Fever of Unknown Origin Investigations

Growing evidence suggests that 2-deoxy-2-[18F]fluoro-D-glucose (18FDG)-positron emission tomography/computed tomography (PET/CT) is a useful imaging technique for the evaluation of fever of unknown origin (FUO). This imaging technique allows for accurate localization of foci of hypermetabolism based on 18FDG uptake in glycolytically active cells that may represent inflammation, infection, or neoplasia. The presence of abnormal uptake can help direct further investigation that may yield a final diagnosis. A lack of abnormal uptake can be reasonably reassuring that these conditions are not present, thereby avoiding unnecessary additional testing. Insurers have not routinely covered outpatient 18FDG-PET/CT for the indication of FUO in the United States. However, data published since 2007 suggest early use in FUO diagnostic evaluations improves diagnostic efficiency and reduces costs. Clinicians and insurers should consider 18FDG-PET/CT as a useful tool when preliminary studies are unrevealing.

Progress Report: Next-Generation Sequencing (NGS), Multiplex Polymerase Chain Reaction (PCR), and Broad-Range Molecular Assays as Diagnostic Tools for Fever of Unknown Origin (FUO) Investigations in Adults

Even well into the 21st century, infectious diseases still account for most causes of fever of unknown origin (FUO). Advances in molecular technologies, including broad-range PCR of the 16S rRNA gene followed by Sanger sequencing, multiplex PCR assays, and more recently, next-generation sequencing (NGS) applications, have transitioned from research methods to more commonplace in some clinical microbiology laboratories. They have the potential to supplant traditional microbial identification methods and antimicrobial susceptibility testing. Despite the remaining challenges with these technologies, publications in the past decade justify excitement about the potential to transform FUO investigations. We discuss available evidence using these molecular methods for FUO evaluations, including potential cost-benefits and future directions.

Why Temperature Screening for Coronavirus Disease 2019 With Noncontact Infrared Thermometers Does Not Work

Coronavirus disease 2019 screening can evaluate large numbers of patients while reducing healthcare exposures and limiting further spread of the virus. Temperature screening has been a focal point of case detection during the pandemic because it is one of the earliest and most frequently reported manifestations of the illness. We describe important factors to consider of screened individuals as well as the measurement process and current outcomes. Optimal temperature-based screening involves both individual and environmental factors as well as reconsideration of the current fever threshold.

Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma

Fever has preoccupied physicians since the earliest days of clinical medicine. It has been the subject of scrutiny in recent decades. Historical convention has mostly determined that 37.0°C (98.6°F) should be regarded as normal body temperature, and more modern evidence suggests that fever is a complex physiological response involving the innate immune system and should not be characterized merely as a temperature above this threshold. Fever of unknown origin (FUO) was first defined in 1961 by Petersdorf and Beeson and continues to be a clinical challenge for physicians. Although clinicians may have some understanding of the history of clinical thermometry, how average body temperatures were established, thermoregulation, and pathophysiology of fever, new concepts are emerging. While FUO subgroups and etiologic classifications have remained unchanged since 1991 revisions, the spectrum of diseases, clinical approach to diagnosis, and management are changing. This review considers how newer data should influence both definitions and lingering dogmatic principles. Despite recent advances and newer imaging techniques such as 18-fluorodeoxyglucose-positron emission tomography, clinical judgment remains an essential component of care.

Hepatitis C Virus-Associated Acalculous Cholecystitis and Review of the Literature

Acute acalculous cholecystitis (AAC) is an infrequently encountered clinical condition associated with high morbidity and mortality. Viral infection associated AAC is rare, but it is most commonly associated with Epstein-Barr virus, cytomegalovirus, dengue virus, hepatitis A, hepatitis B, human immunodeficiency virus, disseminated visceral varicella-zoster virus infection, Zika virus, and hepatitis C. We report on a patient who was first diagnosed with a chronic hepatic C infection and subsequently with acalculous cholecystitis.

Yokenella regensburgei necrotizing fasciitis in an immunocompromised host

We report a case of necrotizing skin infection caused by Yokenella regensburgei in an immunosuppressed patient with orthotopic liver transplantation. Initial bacterial culture identification was suggestive of Hafnia alvei. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) confirmed identification of Y. regensburgei. Necrotizing fasciitis is potentially fatal and requires aggressive management, including early diagnosis, appropriate antibiotic selection, and operative debridement.

Viral (aseptic) meningitis: A review

Viral meningitis is an inflammation of the meninges associated with acute onset of meningeal symptoms and fever, pleocytosis of the cerebrospinal fluid, and no growth on routine bacterial culture. It is sometimes associated with viral encephalitis and meningoencephalitis. Viruses reach the central nervous system (CNS) hematogenously or in a retrograde manner from nerve endings. The viral etiology varies according to age and country. Molecular diagnostics technology has helped improve the rate of pathogen detection reducing unnecessary antibiotic use and length of hospitalization. Most of the viral infections detailed in this article have no specific treatment other than supportive care. Many of the viruses discussed are preventable by vaccination and proper skin protection against transmitting vectors.

Cullen Sign and Grey Turner Sign Revisited

Cullen sign and Grey Turner sign, named after Thomas Stephen Cullen, MB, and George Grey Turner, MBBS, respectively, are signs of abdominal wall hemorrhage and are generally associated with acute pancreatitis. However, the research from which these signs arose was documented long before Cullen and Grey Turner made their contributions. The present article examines the history, pathologic mechanisms, and clinical application of these signs in relation to acute pancreatitis and ectopic pregnancy.

Origin, Evolution and Clinical Application of the Thermometer

Although Galileo, Fahrenheit and Celsius are the names generally associated with the origin of the thermometer and its scale, many others were involved in bringing into existence the instrument we use today to monitor body temperature. In fact, the seed from which the thermometer arose was planted long before those credited with inventing it made their contributions, and nurtured by many other investigators during its evolution and clinical application.

Buerger Test for Erythromelalgia Revisited

Leo Buerger, MD, was the first to describe dependent rubor associated with marked atherosclerosis. Historically, dependent rubor has been described as erythromelalgia (or erythromelia), and terms such as chronic rubor, reactionary rubor, induced rubor, and hyperemic response have also been used to describe this sign associated with peripheral vascular disease. This brief review will reacquaint physicians with the Buerger test, which is used to assess arterial sufficiency, as well as erythromelalgia, and the proposed mechanisms responsible for erythromelalgia. The Buerger test is an important consideration when examining patients for erythromelalgia, which remains distinct from erythema associated with skin and soft-tissue infections.

Infectious Diseases Perspective of Anorectal Abscess and Fistula-in-ano Disease

BACKGROUND

Anorectal abscess and fistula-in-ano is a rare disease with an exemplary prognosis. Most patients are diagnosed with cryptoglandular disease but unusual infections raise difficult antimicrobial management challenges.

METHODS

All primary references identified in PubMed, EMBASE, the ISI Web of Knowledge database and the Cochrane Library, published between 1960 and 2015, using the keywords "anorectal abscess," "fistula-in-ano," "perianal abscess," or "perianal fistula" or all, were uploaded into a database. The databases were also interrogated using keywords specific for each infection type studied.

RESULTS

In all, 52 relevant primary medical publications were identified. There were also 4 relevant organizational standards guideline publications, 1 relevant review and 4 historical publications about the diagnosis and outcomes of anorectal abscess and fistula-in-ano with data derived primarily from prospective and retrospective trials as well as institutional case series to provide an evidence level opinion. The use of antimicrobial therapy in combination with surgical incision and drainage in the treatment of cryptoglandular disease has failed to improved healing times or reduce recurrences or both. Based on limited data, routine antimicrobial therapy may benefit patients with significant comorbid conditions, extensive cellulitis and systemic symptoms. For patients with unusual infecting pathogens (eg, Mycobacterium tuberculosis, Actinomyces species and Chlamydia species) outcomes are favorable with selected antimicrobial therapy agents of various durations.

CONCLUSION

Surgical incision and drainage is the main treatment for anorectal abscess and fistula-in-ano, but a select group of patients with unusual infections benefit from tailored prolonged antimicrobial therapy with the overall recurrence rate remaining low.

Central Venous Access Device-Related Bacillus Cereus Endocarditis: A Case Report and Review of the Literature

Bacillus cereus typically presents as a gastrointestinal infection, but rarely manifests as systemic disease. This report describes a case of B. cereus-related endocarditis that presented as a sickle cell crisis and bacteremia. Initial clinical suspicion was for laboratory contamination of blood cultures. The case herein described is intended to demonstrate an uncommon presentation of B. cereus infection and highlights the value of an aggressive need to further investigate and interpret unexpected blood culture findings in clinical practice, early adequate antimicrobial therapy, prompt diagnosis, and consideration to urgent surgical interventions in such cases.

First Case of Lyme Arthritis Involving a Prosthetic Knee Joint

Borrelia burgdorferi sensu stricto is the most common tick-borne illness in the United States. Arthritis is usually a mani­festation of late dis­ease but has not been associated with cases of periprosthetic joint infections. We report on a patient who was first diagnosed with periprosthetic joint infection and subsequently Lyme arthritis.

Early evolution of the thermometer and application to clinical medicine

By the time of Hippocrates and Galen the notion of fevers and temperature were known. Through ensuing centuries, ancient Greek, Roman, and medieval savants and physicians made additional contributions to the understanding of fever, temperature, and thermometry. By the end of that era, there was a working definition of what constitutes a rationale temperature scale, the distinction between fever as a symptom and fever as a disease, an elaborate classification scheme for temperature, hypotheses as to the causes of fever, and methods for measuring fevers. Based on the definition of fever at that time, the 16th century scientist Galileo promulgated production of thermometric instruments hundreds of years before they were routinely used in the clinical setting. In this work we examine the history of fever and clinical thermometry in the ancient world through the end of the eighteenth century with descriptions of instruments for its measure and human relationship to fever.

Diagnosis and management of Lyme disease

Lyme disease, caused by the bacterium Borrelia burgdorferi, is the most common tick-borne illness in the United States. Transmission occurs primarily through the bite of an infected deer tick (Ixodes scapularis). Identification of an erythema migrans rash following a tick bite is the only clinical manifestation sufficient to make the diagnosis of Lyme disease in the absence of laboratory confirmation. The Centers for Disease Control and Prevention recommends a two-tier serologic testing protocol using an enzyme-linked immunosorbent assay initially, followed by the more specific Western blot to confirm the diagnosis when the assay samples are positive or equivocal. The treatment of Lyme disease is determined mainly by the clinical manifestations of the disease. Doxycycline is often the preferred agent for oral treatment because of its activity against other tick-borne illnesses. Preventive measures include avoiding areas with high tick burdens, wearing protective clothing, using tick repellants (e.g., diethyltoluamide [DEET]), performing frequent body checks and bathing following outdoor activities, and instituting environmental landscape modifications (e.g., grass mowing, deer exclusion fencing) to reduce the tick burden. Although there is controversy regarding treatment of post-Lyme disease syndrome and chronic Lyme disease, there is no biologic or clinical trial evidence indicating that prolonged antibiotic therapy is of benefit.

Update: The diagnosis and management of dengue virus infection in North America

Dengue is a mosquito-transmitted infection that poses significant global health risks for travelers and individuals living in the tropics and subtropics. The reported global incidence has increased dramatically in the past century, with dengue now ranking as the most common cause of febrile illness in travelers. While sporadic cases have been reported within the southern United States since 1980, autochthonous outbreaks have now been described in Hawaii, St. Croix (US Virgin Islands), along the Texas-Mexico border, and, most recently, in Key West, Florida. Although many infections are mild or asymptomatic, 5-10% of patients may experience hemorrhagic disease, with shock and even death. Laboratory identification commonly involves serologic and nucleic acid amplification methods. Due to rising incidence worldwide, physicians should be familiar with the clinical manifestations, laboratory diagnosis, and management of this illness.

Parvovirus B19 and C-reactive protein in blood bank donors: implications for hygiene hypothesis research

Exposure to certain environmental factors during childhood may influence the developing immune system, causing predisposing or protective effects toward development of autoimmune disorders. This study examines the hypothesis that past infection with parvovirus B19, a common childhood infection, is associated with altered levels of subclinical inflammatory activity in presumably healthy adults. Qualitative anti-parvovirus B19 IgG antibody and high-sensitivity C-reactive protein were determined in serum samples from adult blood bank donors. C-reactive protein values of B19 IgG-positive and B19 IgG-negative groups were compared. Analysis was performed on 282 blood bank donor serum samples. Among donors aged 17-49 years (n = 152), B19 IgG-positive samples (57.9%) were associated with significantly lower C-reactive protein levels compared with B19 IgG-negative samples (median C-reactive protein: 1.30 mg/l vs. 2.65 mg/l; p = 0.012 unadjusted (Mann-Whitney U-test); p = 0.014 adjusted for gender and age (logistic regression)). Among donors aged >49 years, median C-reactive protein levels were identical by B19 IgG status. The association of B19 IgG antibody with lower C-reactive protein levels in the serum of younger adults supports the hypothesis that infection in childhood may contribute long-term beneficial adaptive immune responses.

Simultaneous bio-reduction of nitrate, perchlorate, selenate, chromate, arsenate, and dibromochloropropane using a hydrogen-based membrane biofilm reactor

We tested the hypothesis that the H(2)-based membrane biofilm reactor (MBfR) is capable of reducing multiple oxidized contaminants, a common situation for groundwater contamination. We conducted bench-scale experiments with three groundwater samples collected from California's San Joaquin Valley and on two synthetic groundwaters containing selenate and chromate. The actual groundwater sources had nitrate levels exceeding 10 mg-N l(-1) and different combinations of anthropogenic perchlorate + chlorate, arsenate, and dibromochloropropane (DBCP). For all actual groundwaters, the MBfR reduced nitrate to less than 0.01 mg-N l(-1). Present in two groundwaters, perchlorate + chlorate was reduced to below the California Notification Level, 6 microg-ClO(4) l(-1). As(V) was substantially reduced to As(III) for two groundwaters samples, which had influent As(V) concentrations from 3 to 8.8 microg-As l(-1). DBCP, present in one groundwater at 1.4 microg l(-1), was reduced to below its detection limit of 0.01 microg l(-1), which is well below California's 0.2 microg l(-1) MCL for DBCP. For the synthetic groundwaters, two MBfRs initially reduced Se(VI) or Cr(VI) stably to Se degrees or Cr(III). When we switched the influent oxidized contaminants, the new oxidized contaminant was reduced immediately, and its reduction soon was approximately the same or greater than it had been reduced in its original MBfR. These results support that the H(2)-based MBfR can reduce multiple oxidized contaminants simultaneously.