Fever of unknown origin: a clinical approach

Serum Soluble IL-2 Receptors Are Elevated in Febrile Illnesses and Useful for Differentiating Clinically Similar Malignant Lymphomas from Kikuchi Disease: A Cross-Sectional Study

Background: The use of serum soluble interleukin 2 receptor (sIL-2R) for the diagnosis of febrile illnesses has not been examined. In this study, febrile patients were classified according to etiology and disease, and serum sIL-2R levels were evaluated. We determined whether serum sIL-2R is a useful marker for differentiating between malignant lymphoma (ML) and non-ML patients and between patients with ML and Kikuchi disease, which present similar clinical manifestations. Methods: This study was a cross-sectional study and included 344 patients with uncomplicated hemophagocytic syndrome, who had a fever of 38 °C or higher within 1 week of admission to our institution. Patient serum sIL-2R was measured, and the serum sIL-2R values are shown as median and IQR. Results: Serum sIL-2R increased above the upper reference limit in all disease groups with fever. The serum sIL-2R level in ML patients (n = 13) was 4760 (2120-6730) U/mL and significantly higher (p < 0.001) than the level of 998 (640-1625) U/mL in non-ML patients (n = 331). The serum sIL-2R level in ML patients (n = 13) was also significantly higher (p < 0.001) compared with that in patients with Kikuchi disease (n = 20; 705 (538-1091) U/mL). Conclusions: Serum sIL-2R tends to exceed the upper reference limit in patients with febrile illnesses. We conclude that the measurement of serum sIL-2R is useful for differentiating ML from non-ML and ML from Kikuchi disease.

A Rare Presentation of Systemic Lupus Erythematosus in a Patient With Fever of Unknown Origin

This case presents a 23-year-old male with a rare presentation of lupus as fever of unknown origin (FUO). The patient's clinical symptoms, examination findings, and laboratory results painted a complex picture that necessitated considering macrophage activation syndrome and adult-onset Still's disease but ultimately led to the diagnosis of systemic lupus erythematosus. The case emphasizes the importance of including lupus in the differential diagnosis of FUO given the associated risks and higher mortality rates in this demographic, especially in males. Understanding lupus prevalence and classification criteria aids in diagnosis, highlighting the importance of a systematic approach for FUO and emphasizing timely intervention for improved patient outcomes.

A case of thymoma presenting as pyrexia of unknown origin

ABSTRACT

Pyrexia of unknown origin can be caused due to numerous infective and noninfective causes. It poses a diagnostic dilemma to the clinicians and requires a myriad of investigations for the confirmation of diagnosis. Thymomas are rare mediastinal tumors that present as anterior mediastinal mass; however, thymomas presenting as pyrexia of unknown origin has rarely been reported in the literature. We report an interesting case of a middle-aged male who presented as pyrexia of unknown origin due to thymoma.

An Unusual Case of Sarcoidosis with a Prolonged Fever and Progressive Arthropathy

A 70-year-old man had developed a high fever and arthralgia in his right elbow 6 months prior. Loxoprofen improved the symptoms temporarily, but arthropathy developed in other joints. Long-term recurrent arthropathy and the fever caused activity reduction and progressive debilitation. We performed fluorine-18 fluorodeoxyglucose-positron emission tomography and detected a positive accumulation in multiple joints and lymph nodes. A lymph node biopsy revealed epithelioid cell granulomas, which, along with elevated angiotensin-converting enzyme levels, led to the diagnosis of sarcoid arthropathy. After prednisolone administration, the fever and arthralgia resolved, and his activities of daily living improved. Clinicians should be aware of this type of sarcoid arthropathy.

Non-infectious diseases in infectious disease consultation: A descriptive study in a tertiary care teaching hospital

In this retrospective study, we aimed to investigate the frequency, trend, and nature of non-infectious diseases (non-IDs) as the final diagnosis for patients during an infectious disease (ID) consultation in an acute care hospital in Japan. This study included adult inpatients who underwent ID consultations between October 2016 and March 2018. The demographic data, clinical manifestations, and final non-ID diagnoses of cases were explored. Among the 502 patients who underwent ID consultations, 45 (9.0%) were diagnosed with non-IDs. The most common diagnoses were tumors (22.2%, n = 10), connective tissue and collagen vascular diseases (13.3%, n = 6), other inflammatory diseases (8.9%, n = 4), and drug-induced fever (8.9%, n = 4). Multiple logistic regression analysis showed that the presence of consultations for diagnosis (odds ratio [OR], 22.0; 95% confidence interval [CI], 10.1-48.2; p<0.01), consultations from the internal medicine department (OR, 2.5; 95% CI, 1.2-5.2; p = 0.02), and non-bacteremia cases (OR, 5.2; 95% CI, 1.4-19.3; p = 0.01) were independently associated with diagnosed non-IDs. Non-IDs after ID consultations were mainly tumor-related, inflammatory diseases, and drug fever. The presence of consultations for diagnosis, consultations from the internal medicine department and non-bacteremia cases were related to non-IDs among ID consultations. Further research is needed to explore the frequency and pattern of non-IDs to improve the quality of ID consultations in daily practice.

'Functional hyperthermia': a historical overview

The management of low-grade fever in adults has not been codified. This gap is related not only to the numerous possible aetiologies but also to the difficulty of escaping the monocausal model of diseases. This article explores the complex issue of positive signs in 'psychogenic fever' through Reimann's 1930s series. The discussion emphasises Canguilhem's positions regarding vital signs and proposes (1) a semantic clarification of 'habitual hyperthermia' and (2) an amendment of the Belgian diagnostic criteria based on the concept of functional disorder. This paper also suggests following Peirce's pragmatism in the face of an uncommon clinical picture.

Integrating Medical Domain Knowledge for Early Diagnosis of Fever of Unknown Origin: An Interpretable Hierarchical Multimodal Neural Network Approach

Accurate and interpretable differential diagnostic technologies are crucial for supporting clinicians in decision-making and treatment-planning for patients with fever of unknown origin (FUO). Existing solutions commonly address the diagnosis of FUO by transforming it into a multi-classification task. However, after the emergence of COVID-19 pandemic, clinicians have recognized the heightened significance of early diagnosis in patients with FUO, particularly for practical needs such as early triage. This has resulted in increased demands for identifying a wider range of etiologies, shorter observation windows, and better model interpretability. In this article, we propose an interpretable hierarchical multimodal neural network framework (iHMNNF) to facilitate early diagnosis of FUO by incorporating medical domain knowledge and leveraging multimodal clinical data. The iHMNNF comprises a top-down hierarchical reasoning framework (Td-HRF) built on the class hierarchy of FUO etiologies, five local attention-based multimodal neural networks (La-MNNs) trained for each parent node of the class hierarchy, and an interpretable module based on layer-wise relevance propagation (LRP) and attention mechanism. Experimental datasets were collected from electronic health records (EHRs) at a large-scale tertiary grade-A hospital in China, comprising 34,051 hospital admissions of 30,794 FUO patients from January 2011 to October 2020. Our proposed La-MNNs achieved area under the receiver operating characteristic curve (AUROC) values ranging from 0.7809 to 0.9035 across all five decomposed tasks, surpassing competing machine learning (ML) and single-modality deep learning (DL) methods while also providing enhanced interpretability. Furthermore, we explored the feasibility of identifying FUO etiologies using only the first N-hour time series data obtained after admission.

Differential diagnosis of lymphoma with 18F-FDG PET/CT in patients with fever of unknown origin accompanied by lymphadenopathy

PURPOSE

To investigate the value of 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the differential diagnosis of lymphoma in patients with fever of unknown origin (FUO) accompanied by lymphadenopathy and to develop a simple scoring system to distinguish lymphoma from other etiologies.

METHODS

A prospective study was conducted on patients with classic FUO accompanied by lymphadenopathy. After standard diagnostic procedures, including PET/CT scan and lymph-node biopsy, 163 patients were enrolled and divided into lymphoma and benign groups according to the etiology. The diagnostic utility of PET/CT imaging was evaluated, and beneficial parameters that could improve diagnostic effectiveness were identified.

RESULTS

The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PET/CT in diagnosing lymphoma in patients with FUO accompanied by lymphadenopathy were 81.0, 47.6, 59.3, and 72.7%, respectively. The lymphoma prediction model combining high SUVmax of the "hottest" lesion, high SUVmax of the retroperitoneal lymph nodes, old age, low platelet count, and low ESR had an area under the curve of 0.93 (0.89-0.97), a sensitivity of 84.8%, a specificity of 92.9%, a PPV of 91.8%, and an NPV of 86.7%. There was a lower probability of lymphoma for patients with a score < 4 points.

CONCLUSIONS

PET/CT scans show moderate sensitivity and low specificity in diagnosing lymphoma in patients with FUO accompanied by lymphadenopathy. The scoring system based on PET/CT and clinical parameters performs well in differentiating lymphoma and benign causes and can be used as a reliable noninvasive tool.

REGISTRATION NUMBER

This study on FUO was registered on http://www.

CLINICALTRIALS

gov on January 14, 2014, with registration number NCT02035670.

Structured diagnostic scheme clinical experience sharing: a prospective study of 320 cases of fever of unknown origin in a tertiary hospital in North China

BACKGROUND

There has been little research on the long-term clinical outcomes of patients discharged due to undiagnosed fevers of unknown origin (FUO). The purpose of this study was to determine how fever of unknown origin (FUO) evolves over time and to determine the prognosis of patients in order to guide clinical diagnosis and treatment decisions.

METHODS

Based on FUO structured diagnosis scheme, prospectively included 320 patients who hospitalized at the Department of Infectious Diseases of the Second Hospital of Hebei Medical University from March 15, 2016 to December 31,2019 with FUO, to analysis the cause of FUO, pathogenetic distribution and prognosis, and to compare the etiological distribution of FUO between different years, genders, ages, and duration of fever.

RESULTS

Among the 320 patients, 279 were finally diagnosed through various types of examination or diagnostic methods, and the diagnosis rate was 87.2%. Among all the causes of FUO, 69.3% were infectious diseases, of which Urinary tract infection 12.8% and lung infection 9.7% were the most common. The majority of pathogens are bacteria. Among contagious diseases, brucellosis is the most common. Non-infectious inflammatory diseases were responsible for 6.3% of cases, of which systemic lupus erythematosus(SLE) 1.9% was the most common; 5% were neoplastic diseases; 5.3% were other diseases; and in 12.8% of cases, the cause was unclear. In 2018-2019, the proportion of infectious diseases in FUO was higher than 2016-2017 (P < 0.05). The proportion of infectious diseases was higher in men and older FUO than in women and young and middle-aged (P < 0.05). According to follow-up, the mortality rate of FUO patients during hospitalization was low at 1.9%.

CONCLUSIONS

Infectious diseases are the principal cause of FUO. There are temporal differences in the etiological distribution of FUO, and the etiology of FUO is closely related to the prognosis. It is important to identify the etiology of patients with worsening or unrelieved disease.

A Case of Mediastinal Tuberculous Lymphadenitis in a Chronic Dialysis Patient Diagnosed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA)

A 54-year-old woman on dialysis due to chronic renal failure had a fever lasting 2 weeks and was referred to a hospital. Non-enhanced CT and blood tests showed no remarkable findings. She was hospitalized and received an antibacterial drug. Although she was discharged after the fever subsided, she was hospitalized again due to a fever a few days later. A contrast-enhanced CT revealed mediastinal lymphadenopathy, and she was transferred to our hospital for a bronchoscopy. Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) for subcarinal lymph nodes was performed in our hospital. The Polymerase Chain Reaction (PCR) test of the obtained specimen was positive for mycobacterium tuberculosis, and histologically, caseous granulomas were found in the specimen. She was diagnosed with mediastinal tuberculous lymphadenitis, and HREZ (isoniazid, rifampicin, ethambutol, and pyrazinamide) treatment was started. The fever subsided immediately, and she was discharged from our hospital 2 weeks after the initiation of treatment. Thereafter, she received treatment as an outpatient. Since the use of a contrast medium was complicated by dialysis, a non-enhanced CT was performed at first, and it was difficult to make a diagnosis from this. We report this as an informative case that could be diagnosed with EBUS-TBNA, which was easily performed on a patient weakened by prolonged fever and dialysis.

Development of a Reinforcement Learning Algorithm to Optimize Corticosteroid Therapy in Critically Ill Patients with Sepsis

BACKGROUND

The optimal indication, dose, and timing of corticosteroids in sepsis is controversial. Here, we used reinforcement learning to derive the optimal steroid policy in septic patients based on data on 3051 ICU admissions from the AmsterdamUMCdb intensive care database.

METHODS

We identified septic patients according to the 2016 consensus definition. An actor-critic RL algorithm using ICU mortality as a reward signal was developed to determine the optimal treatment policy from time-series data on 277 clinical parameters. We performed off-policy evaluation and testing in independent subsets to assess the algorithm's performance.

RESULTS

Agreement between the RL agent's policy and the actual documented treatment reached 59%. Our RL agent's treatment policy was more restrictive compared to the actual clinician behavior: our algorithm suggested withholding corticosteroids in 62% of the patient states, versus 52% according to the physicians' policy. The 95% lower bound of the expected reward was higher for the RL agent than clinicians' historical decisions. ICU mortality after concordant action in the testing dataset was lower both when corticosteroids had been withheld and when corticosteroids had been prescribed by the virtual agent. The most relevant variables were vital parameters and laboratory values, such as blood pressure, heart rate, leucocyte count, and glycemia.

CONCLUSIONS

Individualized use of corticosteroids in sepsis may result in a mortality benefit, but optimal treatment policy may be more restrictive than the routine clinical practice. Whilst external validation is needed, our study motivates a 'precision-medicine' approach to future prospective controlled trials and practice.

Case report: Rosai-Dorfman disease with rare extranodal lesions in the pelvis, heart, liver and skin

Rosai-Dorfman disease (RDD), a rare form of non-Langerhans cell histiocytosis, can involve systemic extranodal lesions. Skin lesions are the most common, whereas intrapelvic, cardiac, and hepatic lesions are infrequent. The present study describes a 74-year-old woman with multiple extranodal lesions in the pelvis, heart, liver, and skin that were successfully treated with glucocorticoid therapy. She had experienced fever and persistent inflammation without cervical lymphadenopathy for several months and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed abnormal FDG uptake in the left cheek; cervical, axillary, inguinal lymph nodes; periatrium; and pelvis. She was diagnosed with RDD based on skin and pelvic biopsies. Although this was an atypical case without bilateral cervical lymphadenopathy, the FDG-PET detection of inflammatory lesions led to selection of suitable biopsy sites, and pathological examination led to a correct diagnosis. Findings in this patient indicate that RDD can present with an atypical distribution of infrequent extranodal lesions, with attention required to prevent a delayed diagnosis.

The diagnosis and management of suspected lymphoma in general practice

With rapid advancements in diagnosis and treatment of malignancies, the gap between generalists and subspecialists continues to widen, particularly in cancers like lymphoma where the spectrum of disease varies from indolent to rapidly progressive. Prior to establishing with a hematologist/oncologist, patients must be accurately and comprehensively diagnosed and managed for lymphoma in the generalist setting. In the following manuscript, we review the common clinical presentations in which should raise concern for lymphoma. We summarize the literature regarding the role of laboratory studies including complete blood count and peripheral blood flow cytometry, the recommendations for lymph node sampling, the role and selection of imaging modalities, and ideal patient monitoring for high-risk clinical syndromes that may be encountered in lymphoma.

Diagnostic value of FDG-PET/CT in fever of unknown origin

Background

Fever of unknown origin (FUO) is a challenging clinical problem in medicine that needs collaboration of various diagnostic techniques to establish the accurate diagnosis. We evaluated the diagnostic performance of 18F-FDG PET/CT in patients who presented themselves with FUO. Our study included 40 patients with FUO who underwent PET/CT examination and their results were compared to the results of laboratory, histopathological, microbiological investigations and/or response to therapy.

Results

The final diagnosis included malignancy in 20 patients (50%), infectious causes in 7 patients (17.5%) and non-infectious inflammatory causes in 6 patients (15%). Fever resolved without diagnosis in 4 patients (10%), while no definite diagnosis was reached in 3 patients (7%). PET/CT successfully contributed to diagnosis of 35 out of 40 patients with diagnostic accuracy of 87.5%. The sensitivity, specificity, positive predictive value and negative predictive value of PET/CT in our study were 93.5%, 66.7%, 90.6% and 75%, respectively.

Conclusion

PET/CT is a useful tool to investigate and diagnose the cause of FUO. It provides information that can guide the treatment strategy of the patients.

Fever of Unknown Origin and Atrial Fibrillation: A Case Report

Fever of unknown origin describes a temperature greater than 100.9°F which is present on multiple instances for a period over three weeks with no confirmed diagnosis despite a minimum of three outpatient visits, three days of inpatient testing, or one week of extensive outpatient testing. This diagnosis presents challenges in clinical management due to the unknown etiology. This case highlights a fever of unknown origin presenting with new-onset atrial fibrillation in a patient with no previous cardiac history. A 62-year-old Caucasian male presented to the ED with a nine-day history of intermittent fevers and chills. He returned from a rafting trip in North Carolina two weeks ago but reported no tick bites, animal encounters, or river water ingestion. Further evaluation was significant for an elevated white blood cell count and elevated inflammatory markers. Laboratory and radiologic testing for a wide array of infectious and malignant etiologies were unremarkable. Soon after hospital presentation, he developed a fever of 102.9°F with new onset palpitations and chest tightness due to atrial fibrillation. Episodes of atrial fibrillation continued for his seven-day hospital course with more severe symptoms in the evenings. He was administered broad-spectrum antibiotics and tested extensively with no definitive etiology. His fever curve downtrended with max temperatures below 100.9°F on hospital days six and seven with asymptomatic episodes of atrial fibrillation, prompting discharge. He continued to have low-grade fevers measured below 100.9°F for several days post-discharge with no associated symptoms, resulting in a diagnosis of fever of unknown origin following the 21st day. Fever of unknown origin is a clinical challenge, particularly in cases with no diagnosis discovered and cases with potentially life-threatening complications such as atrial fibrillation. This patient had multiple potential etiologies for his condition, but none had sufficient evidence for diagnosis, resulting in uncertainty regarding the ideal management. As a result, constant monitoring with supportive treatments and broad-spectrum antibiotics was utilized. These measures allowed for symptom remission and hospital discharge for outpatient follow-up. This case highlights a rare presentation of fever of unknown origin with new-onset atrial fibrillation in an otherwise healthy adult.

Human brucellosis and fever of unknown origin

BACKGROUND

Human brucellosis has become one of the major public health problems in China, and increases atypical manifestations, such as fever of unknown origin (FUO), and misdiagnosis rates has complicated the diagnosis of brucellosis. To date, no relevant study on the relationship between brucellosis and FUO has been conducted.

METHODS

We retrospectively reviewed the medical charts of 35 patients with confirmed human brucellosis and prospectively recorded their outcomes by telephone interview. The patients were admitted to the Second Affiliated Hospital of Nanchang University between January 01, 2013 and October 31, 2019. Patient data were collected from hospital medical records.

RESULTS

The percentage of males was significantly higher than that of female in FUO (78.95% vs. 21.05%, P < 0.05), and 80% of the patients had a clear history of exposure to cattle and sheep. Moreover, 19 (54%) cases were hospitalized with FUO, among which the patients with epidemiological histories were significantly more than those without (P < 0.05). The incidence of toxic hepatitis in FUO patients was higher than that in non-FUO patients (89% vs. 50%, P < 0.05). Meanwhile, the misdiagnosis rate was considerably higher in the FUO group than in the non-FUO group (100% vs. 63%; P < 0.05).

CONCLUSION

Brucellosis is predominantly FUO admission in a non-endemic area of China, accompanied by irregular fever and toxic hepatitis. Careful examination of the epidemiological history and timely improvement of blood and bone marrow cultures can facilitate early diagnosis and prevent misdiagnosis.

Diagnostic models for fever of unknown origin based on 18F-FDG PET/CT: a prospective study in China

Background

This study aims to analyze the 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) characteristics of different causes of fever of unknown origin (FUO) and identify independent predictors to develop a suitable diagnostic model for distinguishing between these causes. A total of 524 patients with classical FUO who underwent standard diagnostic procedures and PET/CT were prospectively studied. The diagnostic performance of PET/CT imaging was analyzed, and relevant clinical parameters that could improve diagnostic efficacy were identified. The model was established using the data of 369 patients and the other 155 patients comprised the validation cohort for verifying the diagnostic performance of the model.

Results

The metabolic characteristics of the “hottest” lesion, the spleen, bone marrow, and lymph nodes varied for various causes. PET/CT combined with clinical parameters achieved better discrimination in the differential diagnosis of FUO. The etiological diagnostic models included the following factors: multisite metabolic characteristics, blood cell counts, inflammatory indicators (erythrocyte sedimentation rate, C-reactive protein, serum ferritin, and lactate dehydrogenase), immunological indicators (interferon gamma release assay, antinuclear antibody, and anti-neutrophil cytoplasm antibody), specific signs (weight loss, rash, and splenomegaly), and age. In the testing cohort, the AUCs of the infection prediction model, the malignancy diagnostic model, and the noninfectious inflammatory disease prediction model were 0.89 (95% CI 0.86–0.92), 0.94 (95% CI 0.92–0.97), and 0.95 (95% CI 0.93–0.97), respectively. The corresponding AUCs for the validation cohort were 0.88 (95% CI 0.82–0.93), 0.93 (95% CI 0.89–0.98), and 0.95 (95% CI 0.92–0.99), respectively.

Conclusions

18F-FDG PET/CT has a certain level of sensitivity and accuracy in diagnosing FUO, which can be further improved by combining it with clinical parameters. Diagnostic models based on PET/CT show excellent performance and can be used as reliable tools to discriminate the cause of FUO.

Trial registration This study (a two-step method apparently improved the physicians’ level of diagnosis decision-making for adult patients with FUO) was registered on the website http://www.clinical-trials.gov on January 14, 2014, with registration number NCT02035670.

Clinical Characteristics Associated with Bacterial Bloodstream Coinfection in COVID-19

INTRODUCTION

Inappropriate antibiotic use in COVID-19 is often due to treatment of presumed bacterial coinfection. Predictive factors to distinguish COVID-19 from COVID-19 with bacterial coinfection or bloodstream infection are limited.

METHODS

We conducted a retrospective cohort study of 595 COVID-19 patients admitted between March 8, 2020, and April 4, 2020, to describe factors associated with a bacterial bloodstream coinfection (BSI). The primary outcome was any characteristic associated with BSI in COVID-19, with secondary outcomes including 30-day mortality and days of antibiotic therapy (DOT) by antibiotic consumption (DOT/1000 patient-days). Variables of interest were compared between true BSI (n = 25) and all other COVID-19 cases (n = 570). A secondary comparison was performed between positive blood cultures with true BSI (n = 25) and contaminants (n = 33) on antibiotic use.

RESULTS

Fever (> 38 °C) (as a COVID-19 symptom) was not different between true BSI (n = 25) and all other COVID-19 patients (n = 570) (p = 0.93), although it was different as a reason for emergency department (ED) admission (p = 0.01). Neurological symptoms (ED reason or COVID-19 symptom) were significantly higher in the true BSI group (p < 0.01, p < 0.01) and were independently associated with true BSI (ED reason: OR = 3.27, p < 0.01; COVID-19 symptom: OR = 2.69, p = 0.03) on multivariate logistic regression. High (15-19.9 × 109/L) white blood cell (WBC) count at admission was also higher in the true BSI group (p < 0.01) and was independently associated with true BSI (OR = 2.56, p = 0.06) though was not statistically significant. Thirty-day mortality was higher among true BSI (p < 0.01). Antibiotic consumption (DOT/1000 patient-days) between true BSI and contaminants was not different (p = 0.34). True bloodstream coinfection was 4.2% (25/595) over the 28-day period.

CONCLUSION

True BSI in COVID-19 was associated with neurological symptoms and nonsignificant higher WBC, and led to overall higher 30-day mortality and worse patient outcomes.

Pseudogout as a Cause of Fever of Unknown Origin Following Staphylococcal Bacteremia in an Older Patient

The causes of fevers in older adults are numerous and diverse, resulting in fevers of unknown origin that complicate the diagnosis process. Compared to young adults, older adults are characterized by comorbidities, aging-induced physiological changes, decreased homeostasis, reduced activities of daily living, and a diminished quality of life due to disease and aging. Thus, diverse perspectives are required to facilitate the accurate diagnosis of fever in older adults. In this study, we experienced a case of epidermal staphylococcal bacteremia of unknown cause with a persistent fever that eventually led to the diagnosis of cervical pseudogout. A 94-year-old bedridden woman visited our hospital with a chief complaint of persistent fever. She was diagnosed with cervical pseudogout after closely examining the prolonged fever following Staphylococcus epidermidis bacteremia. Noninfectious diseases are frequent causes of unexplained fever in older adults, and systemic inflammatory diseases, such as cervical pseudogout, should be considered during examination.

Comparative Analysis of Human Body Temperatures Measured with Noncontact and Contact Thermometers

Body temperature measurement is one of the basic methods in clinical diagnosis. The problems of thermometry—interpretation of the accuracy and repeatability of various types of thermometers—are still being discussed, especially during the current pandemic in connection with the SARS-CoV-2 virus responsible for causing the COVID-19 disease. The aim of the study was to compare surface temperatures of the human body measured by various techniques, in particular a noncontact thermometer (infrared) and contact thermometers (mercury, mercury-free, electronic). The study included 102 randomly selected healthy women and men (age 18–79 years). The Bland–Altman method was used to estimate the 95% reproducibility coefficient, i.e., to assess the degree of conformity between different attempts. Temperatures measured with contact thermometers in the armpit are higher than temperatures measured without contact at the frontal area of the head. The methods used to measure with contact thermometers and a noncontact infrared thermometer statistically showed high measurement reliability. In order to correctly interpret the result of measuring human body temperature, it is necessary to indicate the place of measurement and the type of thermometer used.

Etiologies of fever of unknown origin in HIV/AIDS patients, Hanoi, Vietnam

BACKGROUND

Fever of unknown origin (FUO) is a challenge for clinicians treating patients with HIV/AIDS. CD4 counts can be helpful in the diagnosis and treatment. This study aimed to determine several common etiologies of FUO stratified by CD4 count levels in HIV/AIDS patients.

METHODS

A cross-sectional retrospective and prospective study was conducted in 195 HIV/AIDS patients with FUO admitted to the National Hospital for Tropical Diseases from January 2016 to June 2019. Clinical parameters, immune status, and etiologies for each patient were recorded. Odds ratios were calculated to compare the distributions of common etiologies in groups with two different CD4 count levels: < 50 cells/mm3 and ≥ 50 cells/mm3.

RESULTS

The proportions of opportunistic infections and noninfectious etiologies were 93.3% and 3.6%, respectively. Tuberculosis was the most common opportunistic infection (46.7%), followed by talaromycosis (29.2%) and Pneumocystis jiroveci (PCP) infection (20.5%). Tuberculosis was predominant in all CD4 level groups. Most patients with talaromycosis had CD4 counts below 50 cells/mm3. In total, 53.8% of the patients were infected by one pathogen. The risks of tuberculosis and talaromycosis in FUO-HIV patients were high when their CD4 counts were below 50 cells/mm3.

CONCLUSIONS

Opportunistic infections, especially tuberculosis, are still the leading cause of FUO in HIV/AIDS patients. Tuberculosis and Talaromyces marneffei (TM) infection should be considered in patients with CD4 cell counts < 50 cells/mm3. This study implies that guidelines for appropriate testing to identify the etiology of FUO in HIV/AIDS patient based on the CD4 cell count should be developed, thereby reducing resource waste.

Too Hot to Handle: A Case of Fever of Unknown Origin

Fever of unknown origin (FUO) is defined as a fever higher than 38.3ºC for at least three weeks. It remains a difficult diagnostic challenge and it carries well over 200 differential diagnoses, including infectious, rheumatologic and malignant etiologies. A methodological approach with clinical deductive reasoning and value-based investigative work-up can establish the diagnosis. This case is about a 76-year-old male with a past medical history of atrial fibrillation, bladder cancer treated with chemotherapy (now in remission) and hydronephrosis with recent ureteropelvic junction stent placement. He presented to the emergency department (ED) for worsening shortness of breath (SOB), weakness, and fevers. His initial workup was notable for a urinary tract infection which was treated with ceftriaxone. However, there was only a limited improvement in the fever. Diagnostic imaging was negative on initial review. He was evaluated by consultants of different specialities including infectious disease, rheumatology, and hematology. Ultimately, the decision was made to discharge the patient home on steroids with further outpatient workup. He returned four weeks later with worsening fever and was found to have new-onset mediastinal lymphadenopathy. A biopsy of an inguinal lymph node was obtained which showed high grade-B cell lymphoma. The patient was continued on prednisone and started on chemotherapeutic agents which included vincristine, rituximab and cyclophosphamide. Shortly after starting treatment, the patient and family elected for hospice. This case demonstrates the importance of continuously questioning the diagnosis at hand and of keeping an open mind when evaluating a patient with FUO. 

A discrepant presentation of bacteremia in the emergency department linked to a Fusobacterium nucleatum infection: a case report

BACKGROUND

Fusobacterium nucleatum is an anaerobic bacterium mainly responsible for acute or chronic infection of the ear, nose, and throat, potentially bacteremic with a risk of extraoral metastatic infection. Bacteremia occurs mainly in the elderly or in immunodeficient individuals, with high mortality. F. nucleatum is not the first cause of tonsillar infection in emergency departments, which are more often the consequence of a viral or streptococcal infection, but it is a risk factor for severe bacterial infection, especially in a viral pandemic context.

CASE PRESENTATION

A 25-year-old European woman with no history presented to the emergency department with fever (38.9 °C), pharyngeal symptoms, intermittent headaches, and alteration of general condition. On examination, she presented odynophagia associated with moderate tonsillar hypertrophy, her neck was painful but flexible. A rapid diagnostic test for beta-hemolytic group streptococcus was negative. First biological analyses revealed an inflammatory syndrome with C-reactive protein of 76 mg/L. Procalcitonin was measured secondarily, and was 2.16 µg/L. Faced with discordant clinical and biological findings, a lumbar puncture was performed, which came back negative. At hour eight, hypotension was observed but corrected after filling with physiological serum. The patient was hospitalized for monitoring, based on a hypothesis of severe viral presentation. At hour 24, pyrexia confirmed this hypothesis. A spontaneous but transient improvement and no new hemodynamic event led to early discharge. At day three, she was rehospitalized for increased and continuous headaches, without hemodynamic severity. A broad-spectrum probabilistic antibiotic therapy of ceftriaxone and metronidazole was started due to first blood cultures positive for anaerobic Gram-negative bacilli, while waiting for identification of the pathogen. Three days later, F. nucleatum was identified. According to the microbiological results, antibiotic therapy was adapted with amoxicillin and clavulanic acid, and no further complications were observed during clinical or complementary examinations. The final diagnosis was a F. nucleatum oropharyngeal infection complicated by bacteremia, without metastatic spread.

CONCLUSION

The etiologies of tonsillar infection are not limited to benign viruses or bacteria. These should not be overlooked in emergency medicine, especially when the clinical presentation is discrepant. A combination of early bacterial investigations as blood culture and close clinical monitoring is the only safe way to detect bacteremia, especially in immunocompetent patients.

The Use of Chitotriosidase as a Marker of Active Sarcoidosis and in the Diagnosis of Fever of Unknown Origin (FUO)

Sarcoidosis is a multi-organ inflammatory granulomatosis with a lung-predominant involvement. The aim of this study was to investigate the use of serum chitotriosidase (CHIT1) in patients with fever of unknown origin (FUO); the patients with confirmed diagnosis of active sarcoidosis were compared with ones affected by inactive or treated sarcoidosis. CHIT1 activity was evaluated in 110 patients initially admitted at the hospital as FUOs. The overall performance of CHIT1 for active sarcoidosis diagnosis was assessed by performing an area under the receiver operating characteristic curve analysis (AUROC). The sarcoidosis patients were significantly older than the FUO patients not affected by sarcoidosis (p < 0.01). CHIT1 showed a good accuracy as a biomarker for active sarcoidosis in patients explored for FUO (AUROC 0.955; CI 95% 0.895–0.986; p < 0.001). A CHIT1 value >90.86 showed 96.8% sensitivity (84.2–99.9) and 85.5% specificity (75–92.8) in discriminating active sarcoidosis from other causes of FUO. CHIT1 significantly discriminated active versus inactive/under treatment sarcoidosis patients (with lower enzyme activity) (ROC analysis, sensitivity: 96.9%, specificity: 94.7%, value >83.01 nmol/mL/h, AUROC: 0.958, 0.862–0.994, p < 0.001) compared to ACE (ROC analysis, sensitivity: 25.8%, specificity: 93.7%, value >65 UI/L). In conclusion, CHIT1 is a reliable/sensitive biomarker of active sarcoidosis, with values significantly decreasing in remitted/treated patients. It significantly discriminates active sarcoidosis from FUO patients, providing a useful tool in the diagnosis-assessing process.

Diagnosing a Patient with Erdheim-Chester Disease during the COVID-19 Pandemic

Background: Erdheim-Chester disease (ECD) is a rare hematopoietic neoplasm of histiocytic origin characterized by an insidious course. The coronavirus disease 2019 (COVID-19) pandemic has put an enormous strain on healthcare systems worldwide both directly and indirectly, resulting in the disruption of healthcare services to prevent, diagnose and manage non-COVID-19 disease. Case Presentation: We describe the case of a 58-year-old male patient with sporadic episodes of self-resolving mild fever and anemia of chronic disease with onset two years before the current presentation. Positron emission/computed tomography scan revealed the presence of moderately hypermetabolic perirenal tissue masses. In order to achieve diagnosis, repeated perirenal tissue biopsies were performed, and the diagnostic evaluation was complicated by the strain put on the healthcare system by the COVID-19 pandemic. The patient contracted SARS-CoV-2 and required hospitalization, but recovered fully. No further ECD target organ involvement was documented. Treatment options were presented, but the patient chose to defer treatment for ECD. Conclusion: A high index of suspicion and multidisciplinary team collaboration is paramount to achieve diagnosis in rare conditions such as ECD. Disruptions in healthcare services in the pandemic milieu may disproportionately affect people with rare diseases and further study and effort is required to better meet their needs in the pandemic setting.

Delayed Diagnosis in a Rare Case of Pulmonary Sarcoidosis Presenting as Unilateral Hilar Lymphadenopathy and Fever of Unknown Origin

In this report, we present a rare case of sarcoidosis presenting as fever of unknown origin with unilateral hilar lymphadenopathy, in contrast with the typical presentation of sarcoidosis. Sarcoidosis presenting with asymmetric or isolated unilateral lymphadenopathy is highly unusual. Sarcoidosis is also an uncommon cause of fever of unknown origin. This atypical presentation led to diagnostic delays in our case. This case report emphasizes the importance of considering sarcoidosis early in the differential diagnosis of fever of unknown origin with unilateral hilar lymphadenopathy.

Long COVID presenting with intermittent fever after COVID-19 pneumonia

A 72-year-old man presented to our hospital with a fever. Chest computed tomography showed typical coronavirus disease 2019 (COVID-19) pneumonia. The fever normalized after a few days, and the pneumonia was alleviated. However, the intermittent fever subsequently re-occurred and persisted for over a month. Various tests, including blood tests, culture tests, and image evaluations, were performed. However, the conclusion was that long COVID was the cause of the intermittent fever as an exclusion diagnosis. Many patients suffer from persistent symptoms of COVID-19, but the symptoms and their durations vary. Here we report a case of prolonged fever after COVID-19 pneumonia.

Ferritin, fever, and frequent visits: Hyperferritinemic syndromes in the emergency department

Fever of unknown origin (FUO) is defined as persistent fevers without an identifiable cause despite extensive medical workup. Emergency physicians caring for patients reporting a persistent, nonspecific, febrile illness should carefully consider potentially serious non-infectious causes of FUO. We present a case of a 35-year-old man who presented to the emergency department (ED) three times over a 10-day period for persistent febrile illness and was ultimately diagnosed with Adult-Onset Still's Disease (AOSD) after a serum ferritin level was found to be over 42,000 μg/L. AOSD, along with macrophage activation syndrome, catastrophic antiphospholipid syndrome, and septic shock comprise the four hyperferritinemic syndromes. These are potentially life-threatening febrile illnesses that characteristically present with elevated ferritin levels. In this article, we highlight the value of a serum ferritin level in the workup of a patient with prolonged febrile illness and its utility in facilitating early diagnosis and prompt treatment of hyperferritinemic syndromes in the ED.

Gastric perforation by fish bone with hepatic abscess formation presenting as prolonged fever

A 70-year-old woman presented to the emergency department with a 3-week history of prolonged fever, asthenia and anorexia, denying other symptoms. Physical examination was unremarkable and the patient admitted for further investigation. Initial laboratory testing showed leucocytosis, elevated C-reactive protein and cholestasis, without hyperbilirubinemia or cytolysis. Abdominal ultrasonography found no abnormalities. Viral serologies, autoimmune tests and blood cultures were collected for further investigation of causes of prolonged fever with hepatic involvement. After two days, Citrobacter koseri was isolated in blood cultures and intravenous (IV) piperacillin-tazobactam initiated. Computed tomography (CT) scan of the abdomen showed a left lobe hepatic abscess with gas and a linear hyperdense image, possibly a foreign body, piercing through the gastric antrum into the abscess. Surgical exploration was done for source control. The abscess was drained and the foreign body, a 3.5 cm long fishbone, was removed. The patient's condition rapidly improved. Gastrointestinal perforation due to the ingestion of sharp and elongated foreign bodies usually occur in ileal loops, where the intestinal wall is thinner, causing extravasation of fluids and air into the peritoneum and typically presents with an acute abdomen. The uncommon location of perforation masked these symptoms leading to the unusual presentation with prolonged fever.

Usefulness of computed tomography for hospitalized adult patients with fever to investigate cause of fever: single-center, retrospective cohort study

Purpose

To verify that physicians’ presumptive diagnosis is the most significant factor for finding any signs related to the cause of fever on computed tomography (CT) images.

Materials and methods

This single-center retrospective cohort study included patients (age ≥ 16 years) who underwent CT to investigate the cause of fever between January 1, 2014, and August 31, 2016. Patients who underwent surgical procedures were excluded. The primary outcome was the presence of suspicious CT findings related to the cause of fever. We performed univariate and multivariate logistic regression analyses, adjusted for CT contrast agent use, quick sequential organ failure assessment score > 1, and C-reactive protein level.

Results

We enrolled 171 patients, of which 57 had CT findings, and 114 did not. Multivariate logistic regression analyses demonstrated a significant difference for the presence of a presumptive diagnosis by the attending physician (odds ratio, 4.99; 95% confidence interval 2.31–10.76; p < 0.01), but not for other covariates, including C-reactive protein.

Conclusions

In hospitalized patients with fever, an attending physicians’ presumptive diagnosis is associated with the presence of fever-related CT findings. Improving the quality of the diagnostic assessment before the CT scan may lead to more appropriate CT imaging use.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11604-021-01117-5.

Hemophagocytic lymphohistiocytosis presented with fever of unknown origin: A case study and literature review

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening clinical syndrome, which may present with FUO. The possible diagnosis of HLH must be considered in the differential diagnosis when a patient presents with FUO.

HMGB1, anti-HMGB1 antibodies, and ratio of HMGB1/anti-HMGB1 antibodies as diagnosis indicator in fever of unknown origin

To evaluate the feasibility of serum HMGB1, anti-HMGB1 antibodies, and HMGB1/anti-HMGB1 ratio as a diagnosis indicator of initial clinical classification in patients with fever of unknown origin (FUO). Ninety-four patients with classical FUO and ninety healthy controls were enrolled in this study. The subjects’ clinical data and serum were collected. The serum concentration of HMGB1 was detected by a commercial HMGB1 ELISA kit, while the serum concentration of anti-HMGB1 antibodies were detected by an in-house built anti-HMGB1 antibodies ELISA kit and further confirmed by immunoblotting. According to the hospital diagnosis on discharge, ninety-four FUO patients were divided into four groups, Infectious disease subgroup, autoimmune disease subgroup, malignant tumor subgroup, and undetermined subgroup. The concentrations of HMGB1 in the infectious disease subgroup and autoimmune disease subgroup were higher than those in the malignant tumor subgroup, undetermined subgroup, and healthy control group. The concentration of anti-HMGB1 antibodies in autoimmune disease subtype group was higher than those in other subgroups as well as healthy control group. According to the distribution of HMGB1 and anti-HMGB1 in scatter plots of the patients with FUO, we found that the ratio of serum HMGB1/anti-HMGB1 is an ideal clinical indicator for differential diagnosis of different subtypes of FUO. The best cut-off was 0.75, and the sensitivity, specificity, and AUC were 66.67%, 87.32%, and 0.8, respectively. Correlation analysis showed that serum concentration of HMGB1 was moderately correlated with CRP in infectious diseases subgroup, and the serum concentration of anti-HMGB1 antibodies was strongly correlated with erythrocyte sedimentation rate in autoimmune disease subgroup. Our study had showed that serum HMGB1/anti-HMGB1 antibodies ratio can help clinicians identify FUO subtypes, thereby avoiding many unnecessary examinations and tests, and improving the effectiveness of clinical diagnosis and treatment of FUO.

Differential diagnosis of brain lesions in a metastatic endometrial carcinosarcoma patient

The differential diagnosis of ring-enhancing brain lesions in a patient with metastatic malignancy may initially seem straightforward, and easily attributed to brain metastases. On rare occasions, the physician needs to avoid anchoring bias by re-evaluating the entire clinical context in which these ring-enhancing brain lesions are found. We report a case of cerebral toxoplasmosis mimicking brain metastases in a patient with metastatic cancer and without a prior history of human immunodeficiency virus. A 65-year-old lady with a recently detected relapse of her endometrial carcinosarcoma presented with a 2-week history of fever with no localising symptoms or signs of infection. The initial investigations were unremarkable. She had daily fever despite empirical broad-spectrum antibiotics. A positron emission tomography-computed tomography (PET-CT) was performed to evaluate the pyrexia of unknown origin, which showed metastatic deposits in the pelvis. A magnetic resonance imaging (MRI) of the brain was subsequently performed due to fluctuating mentation, which reported metastatic disease to the brain. Her pyrexia of unknown origin was attributed to malignancy-related fever. The medical oncologist was cautious about starting systemic treatment because the PET-CT had FDG-avid diffuse ground glass opacities in both lung fields, and requested for a bronchoscopic evaluation, which returned positive for Pneumocystis jirovecii. In light of this new finding, a multi-disciplinary discussion and a review of the brain MRI were undertaken, during which it was concluded that the likelihood of cerebral toxoplasmosis was much higher than brain metastases. She was treated with high dose trimethoprim-sulfamethoxazole for both P. jirovecii pneumonia and cerebral toxoplasmosis, with clinical and radiological improvement. This case highlights the importance of (a) clinical input in interpreting imaging findings, (b) entertaining the possibility of multiple concurrent pathologies explaining a patient’s symptoms, (c) being open to alternate diagnoses when new information surfaces even though the current working diagnosis is the most plausible and (d) multi-disciplinary communication when faced with diagnostic difficulty.

Multidisciplinary Management of a Frequent Attender With Pyrexia of Unknown Origin and Psychotic Symptoms

This case report details the multidisciplinary management of a frequent attender in his early 50s with no fixed abode who presented with pyrexia of unknown origin, complicated by his noncooperation with intervention and treatment because of the development of psychotic symptoms. The case required the involvement of liaison psychiatry, anesthesia, cardiology, radiology, gastroenterology, rheumatology, respiratory, hematology, and social services, highlighting not just multidisciplinary intervention but the benefits of working with a multispeciality team. The patient had previously presented to the emergency department 47 times over an 18-month period. The management during his most recent inpatient stay resulted in the patient living independently and presenting to the hospital only once over the ensuing 7 months.

From TTP to Glomerulonephritis: A Lifetime of Lupus

We report the case of a 56-year-old male patient, who over two decades, sequentially presented with a combination of clinical manifestations. These included thrombotic thrombocytopenic purpura (TTP), right leg deep vein thrombosis (DVT), and eventually constitutional symptoms, arthralgia, diffuse lymphadenopathy, pancytopenia, skin rash, pericarditis, and glomerulonephritis. Serologic tests and renal pathology uncovered a diagnosis of systemic lupus erythematosus (SLE), and immunosuppressive therapy was initiated. Soon after, the patient developed striking cytomegalovirus (CMV) viremia, requiring prolonged antiviral therapy and reduction of immunosuppression. Finally, an acute embolic stroke complicated the disease course. Prompt interventions allowed an excellent clinical outcome.

Exploring Fever of Unknown Origin Intelligent Diagnosis Based on Clinical Data: Model Development and Validation

Background

Fever of unknown origin (FUO) is a group of diseases with heterogeneous complex causes that are misdiagnosed or have delayed diagnoses. Previous studies have focused mainly on the statistical analysis and research of the cases. The treatments are very different for the different categories of FUO. Therefore, how to intelligently diagnose FUO into one category is worth studying.

Objective

We aimed to fuse all of the medical data together to automatically predict the categories of the causes of FUO among patients using a machine learning method, which could help doctors diagnose FUO more accurately.

Methods

In this paper, we innovatively and manually built the FUO intelligent diagnosis (FID) model to help clinicians predict the category of the cause and improve the manual diagnostic precision. First, we classified FUO cases into four categories (infections, immune diseases, tumors, and others) according to the large numbers of different causes and treatment methods. Then, we cleaned the basic information data and clinical laboratory results and structured the electronic medical record (EMR) data using the bidirectional encoder representations from transformers (BERT) model. Next, we extracted the features based on the structured sample data and trained the FID model using LightGBM.

Results

Experiments were based on data from 2299 desensitized cases from Peking Union Medical College Hospital. From the extensive experiments, the precision of the FID model was 81.68% for top 1 classification diagnosis and 96.17% for top 2 classification diagnosis, which were superior to the precision of the comparative method.

Conclusions

The FID model showed excellent performance in FUO diagnosis and thus would be a potentially useful tool for clinicians to enhance the precision of FUO diagnosis and reduce the rate of misdiagnosis.

Long-term follow-up of 89 patients with giant cell arteritis: a retrospective observational study on disease characteristics, flares and organ damage

The objective of the study is to investigate the clinical characteristics and long-term prognosis including flares and organ damage in patients with giant cell arteritis (GCA) from a tertiary referral centre and compare these features in different subgroups. In this retrospective observational study, patients with GCA who were followed up in our vasculitis clinic between 1998 and 2018 were evaluated by a predefined protocol. Patients with and without cranial symptoms were compared for clinical and laboratory features, flares and permanent damage findings. Vasculitis Damage Index and Large Vessel Vasculitis Index of Damage were used for damage assessment. Records of 89 patients (median follow-up time 46 months) were analysed; mean time to diagnosis after initial symptom was longer in patients with acute vision loss (11 ± 4 vs. 4.8 ± 1.1 months p = 0.002). EGG (n = 19) was younger (63 ± 2 vs. 69 ± 1 years old p = 0.01); had higher mean CRP (141.8 ± 107.3 vs. 76.6 ± 67.9 mg/dL p = 0.023) and ESR (120.8 ± 25.1 vs. 99.3 ± 24.3 mm/h p = 0.004) at diagnosis. PET-CT detected large vessel vasculitis in 42/48 (87.5%) cases of the entire cohort. Thirty-one patients had flares and proportion of flared patients was significantly higher in patients with cranial symptoms. At least one damage item (DI) was present in 54 (60.7%) patients. The development of damage was found to be associated with flares. Evaluation of our cohort revealed the importance of early diagnosis for prevention of vision loss in GCA. Patients without cranial symptoms were younger, present with higher inflammatory response and for these, PET-CT was the main diagnostic tool. Relapse rate was higher in patients with cranial symptoms. Flares and accompanying corticosteroid treatment may contribute to organ damage in GCA.

Aetiology of pyrexia of unknown origin in north India

The aetiology of pyrexia of unknown origin (PUO) varies dramatically according to epidemiology. We studied the cause and spectrum of PUO in Indian adults. A total of 152 patients (112 prospectively and 40 retrospectively) met Petersdorf and Beeson's criteria. The diagnostic evaluation was guided by potentially diagnostic clues, based on a 'step-wise' approach. The five main categories, i.e. infectious, neoplastic, non-infectious inflammatory, miscellaneous and undiagnosed comprised 43.4%, 21.5%, 19.7%, 2.0% and 12.5%, respectively. The top three causes were tuberculosis (n = 43, 28.3%), lymphoma (n = 19, 12.5%) and adult-onset Still's disease (n = 12, 7.9%). Tuberculosis predominated in all age groups, and about 70% of cases had the extrapulmonary form, the most common being gastrointestinal. Hodgkin and non-Hodgkin lymphomas were equally distributed, but solid malignancies were uncommon. Adult-onset Still's disease was the second commonest cause in adults aged ≤ 40 years. Fever resolved spontaneously in 12/19 cases of undiagnosed cause. Extrapulmonary tuberculosis remains the most prevalent PUO in India.

Pheochromocytoma presenting as fever of unknown origin, a case report

Introduction: Pheochromocytoma is a generally benign neoplasm derived from chromaffin cells of the adrenal medulla. It is characterized by the production of large amounts of catecholamines and also by the capacity to secrete bioactive peptides such as cytokines, mainly interleukin-1 (IL-1), interleukin-6 (IL-6) and TNF alpha.Case presentation: 24-year-old man, who consulted for fever, myalgia, and choluria. His laboratory tests were compatible with a systemic inflammatory response without infectious or autoimmune causes. However, a fluorodeoxyglucose positron emission tomography (FDGPET) revealed a left adrenal mass, without extra-adrenal lesions. On admission, increased levels of differentiated urine methanephrines, elevated baseline cortisol, non-suppressed adrenocorticotrophic hormone (ACTH), and positive low dose dexamethasone suppression test for cortisol were found. With suspicion of catecholamine and ACTH-producing pheochromocytoma, a tumor resection was performed, which conspicuously resolved all alterations of the inflammatory response. The histologic findings confirmed a pheochromocytoma, but the immunostaining for ACTH was negative. A literature review and the comparison of the findings with other reported cases allowed inferring that this was a case of interleukin-producing pheochromocytoma.Conclusion: Pheochromocytoma may be a cause of febrile syndrome, with IL-6 being the main mediator, which explains the manifestationsof systemic inflammation and ACTH-mediated hypercortisolism.

Adult Onset Still´s Disease (AOSD): A rare condition with a classic presentation. Case Report

Introduction: Adult Onset Still´s Disease (AOSD) is a rare systemic inflammatory disease of unclear etiology, with low incidence and prevalence among the general population. AOSD is a common cause of fever of unknown origin (FUO) in up to 20% of cases. Due to the scarce knowledge about this disease and its diagnosis, it is usually unrecognized in the differential diagnoses, worsening the prognosis and increasing complications in some patients.Case presentation: This is the case of a 32-year-old female patient with prolonged febrile illness, who did not respond to the antimicrobial treatments previously established. She was diagnosed with AOSD according to the Yamaguchi criteria after an extensive exclusion process. She was treated with first-line treatment with corticosteroids, achieving satisfactory results.Conclusions: The diagnosis of AOSD is an exhaustive process. Regardless of the availability of cutting-edge diagnostic tools, the medical history of the patient and an adequate physical examination are the most important aspects to consider.

Infectious disease consultations and newly diagnosed cancer patients: A single-center retrospective observational study

Noninfectious diseases may be diagnosed during infectious disease (ID) consultations. Among non-IDs, cancer diagnosis is important; however, epidemiological data describing the relationship between ID consultations and newly diagnosed cancer patients are scarce. This study described the frequency and tendency of new cancer diagnoses in patients after ID consultation.This retrospective study included adult inpatients who underwent ID consultations between October 2016 and March 2018. The demographic data and clinical manifestations of each case are described.Among the 380 inpatients who underwent ID consultations, 6 (1.6%) received a new cancer diagnosis after ID consultation. Among the initial most likely diagnoses, 3 patients were diagnosed with IDs and 3 were diagnosed with non-IDs. The initial most likely ID diagnosis was important for new cancer diagnoses (P = .004, odds ratio: 11.1, 95% confidence interval: 2.11-57.2); diagnostic errors, as judged by the physicians, occurred in 2 of the 6 cases.While the frequency of establishing new diagnoses during ID consultations is low, coexisting infection and cancer is possible. ID specialists should identify any patterns related to new cancer diagnosis in patients to prevent diagnostic error and improve the quality of diagnosis.

Cobalt hip prosthesis intoxication mimicking an autoimmune disease

Cobalt-containing hip prosthesis may cause systemic toxicity due to the release of cobalt from metal-on-metal (MoM) joint arthroplasty into the bloodstream. High cobalt blood levels can lead to a variety of clinical manifestations, mimicking other disorders, especially autoimmune, hematologic, and infectious diseases. Our purpose is to describe a clinical case of cobalt hip prosthesis intoxication mimicking an autoimmune disease, with systemic inflammation signs, arthro-myalgias unrelated to overt synovitis, and multiple autoantibody positivity. A 69-years-old woman presented with a 1-year history of right coxalgia, recurrent fever, arthro-myalgias, mediastinal and right iliac reactive lymphadenopathy. She underwent hip replacement surgery seven years earlier. The physical examination was unremarkable except for right hip pain. Laboratory tests showed markedly increased inflammatory indices and microbiological tests were all negative. Ultrasound-guided arthrocentesis of right hip yielded limpid fluid with negative cultures. Increased cobalt levels in plasma and urine showed metal intoxication. Magnetic resonance imaging with metal artifact reduction sequence (MARS) confirmed a periprosthetic mass as usually seen in reaction to metal debris. Prosthesis substitution was performed with a resolution of the clinical picture and normalization of cobalt levels.

Role of bone marrow biopsy for fever of unknown origin in the contemporary Australian context

BACKGROUND

Bone marrow biopsy (BMB) is an accepted investigation in fever of unknown origin (FUO) to uncover haematological malignancies, such as lymphoma, and sometimes infections. With the advance in imaging modalities, such as 18-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) to identify the focus of lymphoma, BMB may not contribute to the diagnosis when there are no other clinical features to suggest an underlying haematological disease.

AIM

To investigate the utility of BMB in determining the cause of FUO, when there are no other indications for BMB.

METHODS

Medical records of adult patients who had BMB performed for FUO or febrile illness from 1 January 2005 to 31 December 2014 in four metropolitan tertiary hospitals in Melbourne, Australia were reviewed. Patients with other concurrent indications for BMB, known human immunodeficiency virus infection and previously diagnosed connective tissue diseases were excluded.

RESULTS

Seventy-three patients were included in the study. Fifty-one patients had a final diagnosis for fever (systemic inflammatory diseases, infective, malignancy or other) while 22 patients had no diagnoses. In only 10 patients (13.7%) did BMB contribute to the diagnosis, finding either malignancy or granulomata. However, all these diagnoses could have been made without BMB. Two patients with diffuse large B-cell lymphoma had normal BMB. FDG-PET was helpful in making a diagnosis in eight (25%) out of 32 patients.

CONCLUSION

Performing BMB in patients with FUO and no other haematological abnormalities is of very limited value, and other investigations, such as FDG-PET, may be more likely to help establish a definitive diagnosis.

Educational Case: Febrile Nonhemolytic Transfusion Reaction

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.1.

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.

Noninfectious causes of fever in adults

Fever is a common clinical sign encountered in hospitalized patients and often represents the cardinal sign of infectious processes. However, a number of noninfectious etiologies causing fever should be considered prior to initiating broad-spectrum antibiotic therapy. Reducing unnecessary antibiotic use is crucial in an era of increasing resistance.