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

Cat scratch disease in children with nocturnal fever: A case report

BACKGROUND

Cat scratch disease (CSD) is the most common human infection caused by Bartonella henselae (B. henselae). The main manifestation is self-limited lymphadenopathy that primarily affects adolescents, and typically resolves without treatment within 2-4 months. However, individuals with compromised immune systems or immunodeficiency require specific antibacterial therapy following diagnosis. Due to its low incidence, nonspecific clinical manifestations, and diagnostic limitations, this condition often poses challenges for clinicians in terms of missed diagnoses and misdiagnoses.

CASE SUMMARY

The child was ultimately diagnosed with CSD. The primary manifestations included nocturnal fever, enlargement of lymph nodes in the neck, axilla and groin, and suspected brucellosis; however, both brucellosis tests conducted during the course of the illness yielded negative results. Bone marrow cytology indicated stimulated proliferation. Lymph node biopsy indicated hyperplasia of lymphoid tissue in the cervical lymph nodes (right), with combined immunohistochemical findings indicating reactive hyperplasia. Immunohistochemical analysis revealed CD20 B (+), CD3 T (+), BCL-6 (+), and BCL-2 (-). CD21 FDC networks were present and Ki67 expression in the germinal center was ~80%. Blood next-generation sequencing indicated B. henselae sequence number was 3. Serological test results demonstrated positive antibody response to B. henselae IgG (+), B. henselae IgM (+), Bartonella quintana (B. quintana) IgG (-) and B. quintana IgM (-), and the final diagnosis was CSD.

CONCLUSION

In patients presenting with fever at night and swollen lymph nodes of unknown origin, CSD should be considered.

Fever management in children and insights into fever of unknown origin: a survey among Italian pediatricians

BACKGROUND

Fever is a common symptom in children, but despite existing guidelines, pediatricians may not fully apply recommendations. Fever of Unknown Origin (FUO) is generally referred to as an unexplained prolonged fever. However, a standardized FUO definition and management is missing.

OBJECTIVE

To collect updated data on the approach to fever and FUO among Italian pediatricians.

METHODS

A cross-sectional anonymous survey was conducted among a large sample of primary care and hospital pediatricians. The panel group formulated and proposed a practical FUO definition, using a modified Delphi approach. A 75% consensus was required to reach an agreement.

RESULTS

Among 620 respondents, paracetamol was the first-choice antipyretic for 97.7% of participants, followed by ibuprofen; 38.4% prescribed antipyretics based on a specific body temperature rather than on child's discomfort, while physical methods were almost completely abandoned. Alternate treatment was recommended by 19.8% (123/620) of participants, 16.9% (105/620) would prescribe antipyretics to prevent adverse events following immunization. Regarding FUO diagnosis, 58.3% (362/620) considered as cut-off a body temperature above 38°C; the duration required was one week according to 36.45% (226/620) of participants, two weeks according to 35.32% (219/620). The FUO definition proposed by the expert panel reached 81% of consent. Large agreement was observed on first-level laboratory and instrumental investigations in the diagnostic evaluation of FUO, whereas more discrepancies arose on second and third-level investigations. Compared to what participants reported for the treatment of non-prolonged fever, a significant decrease in the prescription of paracetamol as first-choice drug in children with FUO was observed (80.5%; P < 0.0001). Interestingly, 39% of participants would empirically recommend antibiotics, 13.7% steroids, and 4.5% Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) for persistent FUO.

CONCLUSION

Non-recommended behaviors in fever management persist among pediatricians, including alternating use of paracetamol and ibuprofen, and their prophylactic use for vaccinations. Our data confirm the variability in the definition, work-up, and management of FUO. We observed that in children with FUO paracetamol was significantly less commonly preferred than in non-prolonged fever, which is not supported by evidence. Our findings combined with evidence from existing literature underlined the need for future consensus documents.

Clinical and metagenomic characteristics of lymphadenopathy related to fever of unknown origin in children

BACKGROUND

Diagnosis of fever of unknown origin remains challenge for pediatricians. Lymphadenopathy is a separate entity that mainly originates from infection or malignancy.

METHODS

168 patients with FUO accompanied by lymphadenectasis were reviewed. 33 lymph node tissue samples were examined by mNGS. Differences in clinical characteristics were compared among different disease groups. The value of mNGS in diagnosing and improving the clinical situation was assessed.

RESULTS

Multivariate analysis revealed that hepatosplenomegaly and LDH levels were associated with infectious diseases. Arthralgia was correlated with non-infectious inflammatory diseases. Weight loss and a node located in supraclavicular region may indicate neoplastic diseases. mNGS-positive rate was 60.60%, higher than that obtained with traditional methods. Treatment for 3/4 patients was adjusted according to the pathogen detected by mNGS, and antibiotics uses was discontinued or degraded in over 1/2 of the patients according to mNGS results.

CONCLUSIONS

Clinical characteristics of children with lymphadenopathy related to FUO have limited diagnostic value for distinguishing different kinds of diseases, while mNGS of lymph node tissue serves as a useful tool for identifying infectious diseases, especially those caused by rare pathogens. mNGS results can lead to not only adjustments in targeted treatment but also further confirmation of underlying diseases.

IMPACT STATEMENT

1. The clinical features of children with FUO and lymphadenopathy differ according to disease group,although multivariate analysis indicated little diagnostic value for these features. 2. mNGS on lymph node tissue from children with FUO may serve as a efficient tool for distinguishing infectious diseases from other diseases. This is especially useful when a diagnosis cannot be determined with traditional methods. 3. mNGS targeted treatment can be administered in a timely manner and some underlying diseases can be indicated.

Droplet digital PCR aids in the diagnosis of children with fever of unknown origin --A typical case report

Many clinical conditions can cause fever of unknown origin (FUO) in children, but the etiological diagnosis remains challenging despite the variety of inspection methods available at present. This study aims to investigate the effectiveness of droplet digital polymerase chain reaction (ddPCR) in identifying pathogens in children with FUO as a novel application. A 7-month-old boy failed to obtain etiology evidence for his disease through various tests. After collecting peripheral blood for ddPCR analysis, Staphylococcus aureus and Escherichia coli were detected, and Sanger sequencing confirmed the pathogens. During the disease, the child developed septic arthritis and osteomyelitis in the femur. Despite the patient's fever being removed, his limb activity improving, and inflammatory biomarkers decreasing, avascular necrosis of the femoral head remained after targeted antibiotic treatment and surgery. If the patient had undergone ddPCR analysis at an early stage, it may be possible to avoid sequelae. ddPCR helps identify pathogens in the diagnosis of children with FUO and could be a promising complementary tool.

Identification of Bacteria and Viruses Associated with Patients with Acute Febrile Illness in Khon Kaen Province, Thailand

The majority of cases of undifferentiated acute febrile illness (AFI) in the tropics have an undefined etiology. In Thailand, AFI accounts for two-thirds of illnesses reported to the Ministry of Public Health. To characterize the bacterial and viral causes of these AFIs, we conducted molecular pathogen screening and serological analyses in patients who sought treatment in Chum Phae Hospital, Khon Kaen province, during the period from 2015 to 2016. Through integrated approaches, we successfully identified the etiology in 25.5% of cases, with dengue virus infection being the most common cause, noted in 17% of the study population, followed by scrub typhus in 3.8% and rickettsioses in 6.8%. Further investigations targeting viruses in patients revealed the presence of Guadeloupe mosquito virus (GMV) in four patients without other pathogen co-infections. The characterization of four complete genome sequences of GMV amplified from AFI patients showed a 93-97% nucleotide sequence identity with GMV previously reported in mosquitoes. Nucleotide substitutions resulted in amino acid differences between GMV amplified from AFI patients and mosquitoes, observed in 37 positions. However, these changes had undergone purifying selection pressure and potentially had a minimal impact on protein function. Our study suggests that the GMV strains identified in the AFI patients are relatively similar to those previously reported in mosquitoes, highlighting their potential role associated with febrile illness.

Clinical features of histiocytic necrotizing lymphadenitis in children

Due to its nonspecific clinical characteristics, histiocytic necrotizing lymphadenitis (HNL) is often misdiagnosed as a suppurative cervical lymphadenitis and lymphoma. Thus, this study aimed to investigate the clinical characteristics of HNL in pediatric patients. We retrospectively identified 61 patients with histopathologically confirmed HNL. Clinical and laboratory data, including age, sex, clinical manifestations, laboratory investigations, histological discoveries, treatment, and outcomes, were collected from the medical records to determine associations with extracervical lymph node (LN) involvement. The mean age of patients was 9.7 ± 2.8 years (range, 1.5-14.0 years), and the male-to-female ratio was 2.2:1. The most common systemic symptom was fever in all patients. The median pre-admission and total durations of fever were 13.0 (interquartile range [IQR]: 9.0-22.5 days) and 22.0 days (IQR: 17.0-33.0 days), respectively. Patients with temporary fever (< 2 weeks) had a higher peak temperature and were more likely to undergo LN biopsy after admission than those with a prolonged fever (≥ 2 weeks). Multivariate analysis revealed that peak temperature ≥ 40 °C was significantly associated with a longer fever duration (P = 0.023). Laboratory values showed leukopenia (68.9%), which presented more frequently in solitary cervical LNs than in extracervical LNs (82.4% vs. 52.9%, p = 0.027) in patients with prolonged fever.

CONCLUSIONS

HNL is often misdiagnosed in older children with persistent fever and lymphadenopathy, leading to unnecessary diagnostic tests and evaluations, inappropriate antibiotic administration, and mismanagement. A multidisciplinary team, including primary care providers, rheumatologists, and pathologists, can improve patient outcomes by increasing their awareness of this rare condition.

WHAT IS KNOWN

• Histiocytic necrotizing lymphadenitis (HNL) is characterized by fever, leukopenia, and neck lymphadenopathy with unknown etiology. • The lack of neutrophils or eosinophils in the histology, immunohistochemistry results help distinguish HNL from infectious causes. Although HNL is a self-limiting disease, antibiotics and steroid treatments were used inappropriately.

WHAT IS NEW

• A fever peak ≥ 40 °C was associated with a longer fever duration in HNL patients. Leukopenia presented more frequently in solitary cervical lymph node (LNs) than in extracervical LNs inpatients with prolonged fever. • Steroids are not recommended as a routine treatment, however, in some severe or relapsing cases with persistent symptoms, prednisolone (5 mg twice a day for 2 days) or other steroids (an equivalent dose of prednisolone) responded favorably.

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

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

Are children with prolonged fever at a higher risk for serious illness? A prospective observational study

OBJECTIVES

To describe the characteristics and clinical outcomes of children with fever ≥5 days presenting to emergency departments (EDs).

DESIGN

Prospective observational study.

SETTING

12 European EDs.

PATIENTS

Consecutive febrile children <18 years between January 2017 and April 2018.

INTERVENTIONS

Children with fever ≥5 days and their risks for serious bacterial infection (SBI) were compared with children with fever <5 days, including diagnostic accuracy of non-specific symptoms, warning signs and C-reactive protein (CRP; mg/L).

MAIN OUTCOME MEASURES

SBI and other non-infectious serious illness.

RESULTS

3778/35 705 (10.6%) of febrile children had fever ≥5 days. Incidence of SBI in children with fever ≥5 days was higher than in those with fever <5 days (8.4% vs 5.7%). Triage urgency, life-saving interventions and intensive care admissions were similar for fever ≥5 days and <5 days. Several warning signs had good rule in value for SBI with specificities >0.90, but were observed infrequently (range: 0.4%-17%). Absence of warning signs was not sufficiently reliable to rule out SBI (sensitivity 0.92 (95% CI 0.87-0.95), negative likelihood ratio (LR) 0.34 (0.22-0.54)). CRP <20 mg/L was useful for ruling out SBI (negative LR 0.16 (0.11-0.24)). There were 66 cases (1.7%) of non-infectious serious illnesses, including 21 cases of Kawasaki disease (0.6%), 28 inflammatory conditions (0.7%) and 4 malignancies.

CONCLUSION

Children with prolonged fever have a higher risk of SBI, warranting a careful clinical assessment and diagnostic workup. Warning signs of SBI occurred infrequently but, if present, increased the likelihood of SBI. Although rare, clinicians should consider important non-infectious causes of prolonged fever.