C106-04 Chest Computed Tomography Imaging Features of Children With Necrotizing Pneumonia Due to Mycobacterium Tuberculosis in a Tuberculosis-Endemic Setting

Abstract Rationale Evidence on pediatric necrotizing pneumonia (NP) caused by Mycobacterium tuberculosis (Mtb) is limited and largely confined to case reports. The largest earlier case series from South Africa (n = 32) found Mtb responsible for 25% of pediatric NP, with most cases occurring in HIV-infected children1. Vietnam ranks 13th globally for tuberculosis burden. Distinguishing Mtb-associated NP (Mtb-NP) from bacterial NP remains difficult, as pediatric sputum Xpert detects only 65% of cases. We aimed to describe chest computed tomography (CT) features of pediatric Mtb-NP in a high-burden setting to support clinical differentiation. Methods We conducted a retrospective descriptive case series of children aged 1 month-16 years with Mtb-NP admitted to Children’s Hospital 2, a tertiary referral center in Ho Chi Minh City, Vietnam, from January 2022 to August 2025. Results Among 146 hospitalized NP cases during the study period, 21 (14.4%) were diagnosed as Mtb-NP. Of these, 20 underwent chest CT and were included. Microbiologic confirmation was obtained in 6/20 (1 smear-positive, 1 culture-positive, 4 Xpert-positive); the remaining cases lacked microbiologic evidence but improved on anti-tuberculosis therapy. On chest CT, 67% exhibited both cavitary lesions and low-attenuation necrotic foci within areas of consolidation; 33% showed low-attenuation necrosis without cavitation. Necrosis was bilateral in 40% and confined to the right lung in 40%. The largest necrotic foci most often involved the right upper, right lower, and left lower lobes (each 27%). Pleural effusions occurred in 86% (similar left-right distribution); 7% were bilateral, and 62% of effusions were septated. Concomitant pneumothorax was present in 33%, bronchiectasis in 27%, and atelectasis in 33%. Lymphadenopathy was observed in all cases; median node size 15 mm [IQR 12-18]; 53% showed central nodal necrosis and 27% had nodal calcification. Conclusions Lymphadenopathy and pleural effusions are very common in pediatric Mtb-NP. Pulmonary involvement is rarely confined to the left lung. Central nodal necrosis was present in about half of cases. 1 Jacobs C., Goussard P., Gie R. P. Mycobacterium tuberculosis, a cause of necrotising pneumonia in childhood: a case series. International Journal of Tuberculosis and Lung Disease. 2018;22(6):614-616. This abstract is funded by: None