Pulmonary Sequestration as a Rare Cause of Recurrent Lung Abscess: A Case Report in an Endemic Tuberculosis Setting

Abstract Pulmonary sequestration is a rare congenital anomaly involving non-functioning lung tissue that lacks connection to the tracheobronchial tree and receives blood supply from systemic arteries. It is often incidentally detected during prenatal ultrasound or imaging for other conditions. When symptomatic, it can mimic common pulmonary diseases. We present a 29-year-old immunocompetent Filipino female with a seven-year history of recurrent non-massive hemoptysis and left-sided pleural effusion. Without prior comorbidities or smoking history, her case underscores the diagnostic challenges of pulmonary sequestration, especially in regions where tuberculosis (TB) is often an initial diagnosis. The patient underwent multiple left-sided chest pigtail insertions for pleural effusions, which were later removed after minimal drainage. A year before presentation, she had completed a six-month anti-TB regimen empirically.Four months before admission, a chest computed tomography (CT) scan revealed a lung abscess, prompting fiberoptic bronchoscopy. Bronchoalveolar lavage (BAL) grew Pseudomonas aeruginosa sensitive to piperacillin-tazobactam, and she was treated with culture-guided antibiotics. Tests for TB (Xpert MTB/Rif), fungal, and blood cultures were negative. Despite adherence to treatment, she continued to present with hemoptysis, anorexia, and fever.On examination, she had multiple dental caries, which could be a source of recurrent infection. A chest radiograph showed a large cavity with an air-fluid level, and she was treated empirically with Ceftazidime and Metronidazole. HIV and diabetes screenings were negative. A repeat CT showed left-sided compressive atelectasis and compression of the lingular bronchus. Further bronchoscopy and drainage yielded minimal output, and BAL isolated Proteus mirabilis sensitive to Ceftazidime. She ultimately underwent thoracotomy with left lower lobectomy, with histopathology confirming intralobar pulmonary sequestration. Postoperative recovery was uneventful.This case illustrates the importance of including pulmonary sequestration in the differential diagnosis of recurrent lung infections and hemoptysis, particularly in young, immunocompetent patients who do not respond to standard treatments. In tuberculosis-endemic regions, chronic infections like tuberculosis are common initial considerations. However, this case highlights that unusual causes, such as congenital anomalies, should also be considered, especially with atypical or recurrent bacterial pathogens. Intralobar sequestration, unlike extralobar sequestration, often presents with recurrent infections due to its lack of bronchial communication, which predisposes it to stasis and infection. Here, unusual organisms (Pseudomonas aeruginosa and Proteus mirabilis) should have raised suspicion for an underlying structural anomaly earlier, potentially guiding imaging.Awareness of pulmonary sequestration in recurrent or unresolved pulmonary infections is critical, mainly where tuberculosis is prevalent. Early recognition and surgical intervention can significantly improve outcomes.