A46-48 Ex-Vacuo Pneumothorax Following Drainage of a Massive Tuberculous Effusion in Early Pregnancy - A Case of Reversible Lung Entrapment

Abstract Introduction Ex-vacuo pneumothorax is a rare complication of large-volume pleural drainage, reflecting a non-expandable lung due to visceral pleural restriction. Tuberculous pleuritis is a known cause, but occurrence in pregnancy—especially with reversible lung entrapment—is extremely uncommon. Recognizing this entity after drainage is essential to avoid misdiagnosis as iatrogenic pneumothorax and prevent unnecessary repeat drainage or intervention. Case A 37-year-old G2P1 at 7 weeks’ gestation presented with a two-week history of cough, intermittent fever, and exertional dyspnea initially attributed to pregnancy. Obstetric evaluation showed absent fetal heart tones, and she was managed as incomplete abortion. Physical examination revealed decreased breath sounds on the right lung, and imaging demonstrated a massive right pleural effusion (∼3–4 L on ultrasound). Diagnostic thoracentesis yielded 720 mL of cloudy, serous fluid. Pleural fluid analysis showed an exudative, lymphocyte-predominant effusion (protein 55.6 g/L vs serum 63.3 g/L; LDH 167 U/L vs serum 187 U/L; lymphocytes 99%) with glucose 199 mg/dL. GeneXpert MTB/RIF and cultures were negative; cytology showed chronic inflammatory changes without malignancy. Chest tube drainage yielded an additional 2.1 L, after which a large right pneumothorax with failure of lung re-expansion developed, consistent with ex-vacuo pneumothorax. Pleural biopsy revealed non-caseating granulomatous inflammation consistent with tuberculous pleuritis. Controlled suction at –12 cm H2O achieved gradual re-expansion with near-complete expansion by day 5. CT imaging demonstrated cavitary pulmonary tuberculosis in the right lower lobe and a minimal loculated right pneumohydrothorax without a definite pleural rind. Antituberculosis therapy (HRZE) was initiated. Discussion and Conclusion Lung entrapment is a form of non-expandable lung caused by active pleural inflammation and may be reversible, unlike trapped lung, which results from fibrosis and is irreversible. In TB-endemic regions, diagnosis of tuberculous pleuritis in pregnancy is often delayed due to overlapping pregnancy symptoms and hesitancy to pursue imaging or invasive evaluation. Advanced or untreated tuberculosis is associated with adverse maternal and pregnancy outcomes, including pregnancy loss, underscoring the importance of early recognition. Thus, a massive pleural effusion in pregnancy should raise suspicion for tuberculosis; pleural biopsy remains valuable when microbiologic yield is limited. This case demonstrates reversible lung entrapment from tuberculous pleural disease and highlights the importance of distinguishing ex-vacuo from iatrogenic pneumothorax. Early recognition and cautious negative-pressure suction enabled safe lung re-expansion in this pregnant patient with early pregnancy loss. This abstract is funded by: None