Recomendaciones de la Sociedad Española de Infectología Pediátrica sobre el diagnóstico y tratamiento de las adenitis por micobacterias no tuberculosas

Development and Evaluation of an NTM-IGRA to Guide Pediatric Lymphadenitis Diagnosis

BACKGROUND

Diagnosis of nontuberculous mycobacteria (NTM) infections remains a challenge. In this study, we describe the evaluation of an immunological NTM-interferon (IFN)-γ release assay (IGRA) that we developed using glycopeptidolipids (GPLs) as NTM-specific antigens.

METHODS

We tested the NTM-IGRA in 99 samples from pediatric patients. Seventy-five were patients with lymphadenitis: 25 were NTM confirmed, 45 were of unknown etiology but compatible with mycobacterial infection and 5 had lymphadenitis caused by an etiologic agent other than NTM. The remaining 24 samples were from control individuals without lymphadenitis (latently infected with M. tuberculosis , uninfected controls and active tuberculosis patients). Peripheral blood mononuclear cells were stimulated overnight with GPLs. Detection of IFN-γ producing cells was evaluated by enzyme-linked immunospot assay.

RESULTS

NTM culture-confirmed lymphadenitis patient samples had a significantly higher response to GPLs than the patients with lymphadenitis of unknown etiology but compatible with mycobacterial infection ( P < 0.001) and lymphadenitis not caused by NTM ( P < 0.01). We analyzed the response against GPLs in samples from unknown etiology lymphadenitis but compatible with mycobacterial infection cases according to the tuberculin skin test (TST) response, and although not statistically significant, those with a TST ≥5 mm had a higher response to GPLs when compared with the TST <5 mm group.

CONCLUSIONS

Stimulation with GPLs yielded promising results in detecting NTM infection in pediatric patients with lymphadenitis. Our results indicate that the test could be useful to guide the diagnosis of pediatric lymphadenitis. This new NTM-IGRA could improve the clinical handling of NTM-infected patients and avoid unnecessary misdiagnosis and treatments.

Thoracic empyema due to nontuberculous mycobacteria in an immunocompetent patient without pulmonary disease: a case report

BACKGROUND

Pleural involvement by non-tuberculous mycobacteria (NTM), especially NTM empyema in the immunocompetent patient without pulmonary diseases is a rare disease. It is difficult to diagnose with only a few cases of immunodeficient patients in the literature.

CASE PRESENTATION

We describe a 63-year-old male with empyema due to NTM and highlight the challenges of diagnosis.

CONCLUSIONS

Non-tuberculous mycobacterial infection should be considered as a cause of pleuritis or empyema without pulmonary disease, however it is a real diagnostic dilemma.

Interferon-Gamma Release Assays Differentiate between Mycobacterium avium Complex and Tuberculous Lymphadenitis in Children

OBJECTIVES

To assess the performance of interferon-gamma release assays (IGRAs) in the differential diagnosis between Mycobacterium avium complex (MAC) and tuberculosis (TB) in children affected with subacute/chronic submandibular/cervical lymphadenitis.

STUDY DESIGN

Multicenter observational study comparing children with microbiologically confirmed MAC lymphadenitis from the European NontuberculouS MycoBacterial Lymphadenitis in childrEn study with children with TB lymphadenitis from the Spanish Network for the Study of Pediatric TB database.

RESULTS

Overall, 78 patients with MAC and 34 with TB lymphadenitis were included. Among MAC cases, 44 out of 74 (59.5%) had positive tuberculin skin test (TST) results at the 5-mm cut-off, compared with 32 out of 33 (97%) TB cases (P < .001); at the 10-mm cut-off TST results were positive in 23 out of 74 (31.1%) vs 26 out of 31 (83.9%), respectively (P < .001). IGRA results were positive in only 1 out of 32 (3.1%) patients with MAC who had undergone IGRA testing, compared with 21 out of 23 (91.3%) TB cases (P < .001). Agreement between TST and IGRA results was poor in MAC (23.3%; κ = 0.017), but good in TB cases (95.6%; κ = 0.646). IGRAs had a specificity of 96.9% (95% CI 84.3%-99.8%), positive predictive value of 95.4% (95% CI 78.2%-99.8%), and negative predictive value of 93.9% (95% CI 80.4%-98.9%) for TB lymphadenitis.

CONCLUSIONS

In contrast to TST, IGRAs have high specificity, negative predictive value, and positive predictive value for TB lymphadenitis in children with subacute/chronic lymphadenopathy, and consequently can help to discriminate between TB and MAC disease. Therefore, IGRAs are useful tools in the diagnostic work-up of children with lymphadenopathy, particularly when culture and polymerase chain reaction results are negative.

Diagnosis of nontuberculous mycobacterial lymphadenitis: the role of fine-needle aspiration

Nontuberculous mycobacterial lymphadenitis often presents a diagnostic challenge. This study aimed to evaluate the role of fine-needle aspiration cytology in the diagnosis of nontuberculous mycobacterial lymphadenitis in children. We conducted a retrospective review of fine-needle aspiration cytology performed in patients < 17 year-old with subacute lymphadenitis from 2003 to 2016 in a tertiary hospital in Spain. Confirmed nontuberculous mycobacterial lymphadenitis (isolation of nontuberculous mycobacterial in culture from fine-needle aspiration cytology or biopsy samples) and probable nontuberculous mycobacterial lymphadenitis ("granulomatous inflammation" in cytopathologic examinations from fine-needle aspiration cytology or biopsy and clinical-epidemiological history compatible with nontuberculous mycobacterial) were selected. Forty-one patients with nontuberculous mycobacterial lymphadenitis were included: 14 confirmed and 27 probable. Fine-needle aspiration cytology was done in all of them. For 34 patients with excised lymphadenopathy, cytopathology from fine-needle aspiration cytology was concordant with biopsy in 100% cases. Culture results were available from 78.0% (32/41) of patients with fine-needle aspiration cytology and from 85.3% (29/34) with excisional biopsy. Among 22 patients with microbiological results from fine-needle aspiration cytology and biopsy, fine-needle aspiration cytology allowed advanced results in concordance with biopsy or with positive isolation not found in biopsy in 90.1% (20/22) of patients. Sensitivity of nontuberculous mycobacterial cultures obtained by fine-needle aspiration cytology compared to biopsy was 45.5% vs. 36.4% (p = 0.07). Two patients with previous skin alterations presented fistulas after fine-needle aspiration cytology (4.9%); no other complications were described.Conclusion: Fine-needle aspiration cytology provides quick cytopathologic information and is an accurate and safe technique for the diagnosis of nontuberculous mycobacterial lymphadenitis, especially in cases with challenging work-up. What is Known: • Nontuberculous mycobacterial (NTM) infection is an important cause of subacute lymphadenitis in children. • Fine-needle aspiration cytology (FNAC) is an available technique for the diagnosis of lymphadenitis of unknown etiology. What is New: • FNAC is an accurate and safe technique for the diagnosis of NTM lymphadenitis in children. • FNAC can provide reliable samples for cytopathological studies and even a better sensitivity for microbiological culture than excisional biopsy in the study of suspected NTM lymphadenitis.

[Lymphadenitis due to non-tuberculous mycobacteria: Experience over 15 years]

OBJECTIVE

To study the epidemiology, clinical features, diagnosis, therapeutic management, and outcome of non-tuberculous mycobacterial lymphadenitis in a paediatric population of Aragón (Spain).

MATERIAL AND METHODS

A retrospective study was conducted on patients under 15 years-old diagnosed with non-tuberculous mycobacterial lymphadenitis between the years 2000 and 2015.

INCLUSION CRITERIA

patients with lymphadenitis and positive culture. Quantitative values are shown as mean, rank, and standard deviation, and qualitative data as frequencies.

RESULTS

Twenty-seven cases were registered, with a mean age of presentation of 39.9 months (range 10 months-8 years). The mean time between the symptoms onset and first consultation was 1.7±1.1 months. The most frequent location was sub-maxilar in 17/27 cases (63%), on the right side in 59.3%, and size 2.96±1.26cm. Fistulae were observed in 16/27 cases. Tuberculin test was greater than 10mm in 7/24 (29.1%). Microbiological cultures were positive for Mycobacterium avium in 14/27 (51.9%), Mycobacterium intracellulare 3/27 (11.1%), and Mycobacterium lentiflavum 3/27 (11.1%). Combined treatment of antibiotics and surgery was given in 16/27 cases (59.8%), medical treatment only in7/27 (25.9%), and surgical exeresis alone in 4/27 (14.8%). Two patients required a new surgery, and one showed severe neutropenia secondary to rifabutin. Only one case (3.7%) suffered from temporary facial palsy as sequel.

CONCLUSIONS

The most frequent treatment was the combination of antibiotics and surgery. Delay in diagnosis seemed to be responsible for the limited number of exeresis as first option, only one for every seven patients.