Clinical and blood gas characteristics of mycoplasmal pleural effusion and tuberculous pleural effusion in pediatric patients: a retrospective case-control study

Abstract

Background Mycoplasma pneumoniae pneumonia-related pleural effusion (MP-PPE) and tuberculous pleural effusion (TPE) are common pediatric respiratory diseases. This study aimed to investigate their clinical characteristics, serum markers, and pleural fluid characteristics in pediatric patients. Methods The clinical and imaging characteristics, serum inflammatory indicators, pleural fluid analysis, and biochemistry and blood gas analysis results from 98 children aged 2–14 years who were hospitalized in the Pediatric Respiratory Department of Shengjing Hospital of China Medical University from 2018 to 2021 for MP-PPE or TPE were retrospectively examined. Results There were 28 (40%) males and 44 (60%) females in the MP-PPE group and 18 (69%) males and 8 (31%) females in the TPE group (p < 0.05). There was no statistically significant between-group difference in the age ranges of the MP-PPE group (2–13 years, mean age 7.55 ± 3.29 years) and TPE group (5–14 years, mean age 9.69 ± 3.70 years) (p > 0.05). The duration of fever before admission was 12.54 ± 6.95 and 7.77 ± 4.00 days in the MP-PPE and TPE groups, respectively (t = 2.324, p < 0.05). The duration of cough before admission was 15.04 ± 6.86 and 5.90 ± 4.81 days in the MP-PPE and TPE groups (t = 3.972, p < 0.05). Serum neutrophil percentage and C-reactive protein, procalcitonin, interleukin-6, lactate dehydrogenase (LDH), D-dimer, and alanine transaminase levels were significantly higher in the MP-PPE group than in the TPE group. CD3+, CD3 + CD8+, CD3 + CD4+, CD16 + CD56+, and CD19 + counts were lower in the MP-PPE group. There were significant between-group differences in white blood cell count and hemoglobin, fibrinogen, and immunoglobulins (IgA, IgM, and IgG) levels (p > 0.05). There was no significant between-group difference in adenosine deaminase level (p > 0.05). Finally, while there were significant between-group differences in pleural fluid pH, PaCO2, and pleural fluid lactate and blood gas glucose levels (p < 0.05), there was no significant between-group difference in pleural fluid PaO2 (p > 0.05). Conclusions Serum and pleural fluid LDH levels were elevated in the MP-PPE group compared to the TPE group. Our findings could be used to help distinguish MP-PPE from TPE. Blood gas analysis results revealed that the MP-PPE group had a higher pH and was predominantly alkaline compared with the TPE group, which is also a significant finding for differentiating MP-PPE from TPE.