[Diagnosis of infectious lymphadenitis]

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.

Management of Infectious Lymphadenitis in Children

Lymphadenopathy is an irregularity in the size and texture of the lymph nodes, which is quite common in childhood. When the enlargement of lymph nodes is caused by inflammatory and infectious processes, it is called lymphadenitis. The main objective of this manuscript is to summarize the common infectious etiologies and presentations of lymphadenitis in children providing a management guide for clinical practice. PubMed was used to search for all of the studies published up to April 2021 using keywords such as "lymphadenitis" and "children". Literature analysis showed that the differential diagnosis for lymphadenitis in pediatrics is broad. Although lymph node enlargement in children is usually benign and self-limited, it is important to exclude malignant etiology. In most cases, history and physical examination allow to identify the correct diagnosis and start a proper treatment with a prompt resolution of the lymphadenopathy. However, particularly in the case of persistent lymphadenitis, determining the cause of lymph node enlargement may be difficult, and the exact etiology may not be identified despite extensive investigations. Further studies should develop and validate an algorithm to assist pediatricians in the diagnosis and timely treatment of lymphadenitis, suggesting situations in which a watchful waiting may be considered a safe approach, those in which empiric antibiotic therapy should be administered, and those requiring a timely diagnostic work-up.

Detection of Bartonella in cat scratch disease using a single-step PCR assay kit

PURPOSE

Bartonella is an increasingly isolated emerging pathogen that can cause severe illness in humans, including cat scratch disease (CSD). The bacteria are difficult to grow and thus many detection methods have been developed, especially molecular. We previously developed a PCR method targeting ribC to identify Bartonella sp. A manufactured kit (RealCycler BART, Progenie Molecular) was commercialised shortly thereafter for the detection of Bartonella infection, including Bartonella henselae.

METHODOLOGY

We performed a comparison between this test and our in-house PCR assay on 73 lymphadenopathy samples sent to the laboratory for suspicion of CSD.Results/Key findings. Among the 28 positive samples for Bartonella, 21 were identified by the two PCR assays, and seven by the commercial kit only.

CONCLUSION

The performance of this commercial kit suggests that it could be a suitable alternative to our in-house PCR assay, highlighting the importance of the molecular methods used to diagnose CSD.