Pediatric mediastinal tuberculosis: Exploring the diagnostic precision of endobronchial ultrasound and ancillary investigations.

Background: Mediastinal Tuberculosis (TB), although a common presentation of TB in children, has a very low rate of microbiological confirmation. This is because of the difficulty in acquiring appropriate tissue samples for microbiological confirmation. Endobronchial ultrasound (EBUS) and esophageal ultrasound with a bronchoscope (EUS-B) offer a safe, effective, and minimally invasive modality of sampling in these children. We present our institutional experience on EBUS/EUSB and the various ancillary investigations for mediastinal TB.

Methods: This is a single-center retrospective study among children who underwent EBUS/EUS-B for a mediastinal nodal lesion. The primary objective of the study was to analyze the diagnostic accuracy of histopathology and various microbiological investigations, through EBUS/EUS-B guided TBNA, in the diagnosis of mediastinal TB. The secondary objective was to ascertain the safety of EBUS/EUS-B.

Results: A total of 50 children underwent EBUS/EUS-B at our center, of those 26 (17 girls, mean age 11.7 years) were diagnosed with mediastinal TB. Fever was the most common presenting symptom (85%) and only seven children (26%) had a concomitant pulmonary involvement. The diagnostic performance of various investigations was as follows: Acid-fast bacilli (AFB) smear (sensitivity - 86.6%, specificity - 82.9%, NPV-93.5%, PPV - 68.4%), Xpert Ultra (sensitivity -100%, specificity - 68.5%, NPV - 100%, PPV - 57.7%), and cytology (sensitivity - 100%, specificity - 82.9%, NPV - 100%, PPV - 71.4%). A microbiological confirmation was attained in 81% of the children. There were no major complications in any of the procedures.

Conclusion: EBUS/EUSB is an effective and safe investigation for the diagnosis of mediastinal TB in children.