Diagnostic challenges of parapneumonic and tuberculous pleural effusion in children: A 1-year hospital-based study in eastern India

Background: Pediatric pleural effusion is a common yet heterogeneous clinical condition with significant diagnostic and therapeutic implications. Parapneumonic effusion (PPE) and tuberculous pleural effusion (TPE) are the predominant etiologies, but overlapping clinical features frequently delay accurate differentiation. Pleural fluid biochemical and microbiological analyses are therefore essential for timely diagnosis. Aims and Objectives: The aim of the study was to evaluate the biochemical and microbiological profiles of pleural effusion in children and identify consistent parameters for distinguishing parapneumonic from tuberculous causes. Materials and Methods: This hospital-based cross-sectional study was conducted at a tertiary care center in Eastern India between 2018 and 2019 among children aged 1 month–12 years. Thoracocentesis was performed in all suspected cases. Pleural fluid was analyzed for protein, lactate dehydrogenase (LDH), glucose, and adenosine deaminase (ADA), along with microbiological tests including Ziehl–Neelsen (ZN) staining and cartridge-based nucleic acid amplification testing (CBNAAT). Results: Among 61 cases, PPE was the predominant etiology (73.77%), mainly affecting children aged 1–<5 years (mean 3.6 years) and accounting for all infant cases. TPE constituted 14.75% and was observed exclusively in children older than 5 years (mean 9.57 years). TPE demonstrated significantly higher pleural protein (4.27 vs. 3.37 g/dL) and markedly elevated ADA levels (154.33 vs. 26.64 IU/L; P<0.0001), whereas PPE showed higher LDH levels (628 vs. 256.5 IU/L). Microbiological yield for TPE was low, with 0% positivity on ZN staining; CBNAAT modestly improved detection to 22.22%. Conclusion: Age distribution provides an important clinical indicator. While paucibacillary TPE renders ZN staining ineffective, the combination of hyperproteinemia and highly elevated ADA levels serves as a robust diagnostic tool for tuberculosis in resource-limited settings.