Postpartum Immune Modulation and Reactivation of Latent Tuberculosis: A Case of Active Pulmonary Tuberculosis

Background

Tuberculosis (TB) remains an important cause of morbidity worldwide, with progression from latent tuberculosis infection (LTBI) to active disease influenced by host immune status. Pregnancy is associated with significant alterations in cell-mediated immunity, and the postpartum period is characterized by further immune modulation that may contribute to reactivation of previously contained Mycobacterium tuberculosis. We present a case of active pulmonary and pleural tuberculosis occurring approximately one year after childbirth in a woman with remote TB exposure in Ecuador. This case highlights the potential contribution of pregnancy-associated immune alterations to TB reactivation and the importance of maintaining clinical suspicion despite initially negative acid-fast bacilli (AFB) testing.

Case Presentation

A 28-year-old woman with remote tuberculosis exposure in Ecuador presented with one week of severe right-sided chest pain, dyspnea, cough, decreased appetite, and nightly fevers. Approximately one year earlier, following childbirth, she developed a left-sided pleural effusion concerning empyema requiring chest tube placement. Despite counseling regarding the need for further evaluation and treatment, she declined additional care. On re-presentation one year later, chest radiography demonstrated a moderate loculated right pleural effusion with right perihilar and mass-like opacities. Computed tomography of the chest revealed bilateral pulmonary nodules and multiple cavitary lesions, including a 3.4 × 2.8 cm right upper-lobe cavity, raising concern for active tuberculosis. QuantiFERON-TB testing was positive. Initial AFB smear was negative; however, M. tuberculosis PCR was positive, confirming active tuberculosis. Given the significant pleural and pulmonary involvement, the patient underwent bronchoscopy with bronchial washings and placement of a pigtail catheter and right chest tube for pleural drainage. She was subsequently started on standard RIPE therapy with rifampin, isoniazid, pyrazinamide, and ethambutol. Infectious Disease, Pulmonology, and the local health department coordinated ongoing treatment and follow-up.

Findings

Although the initial AFB smear was negative, QuantiFERON-TB testing was positive and M. tuberculosis PCR confirmed active tuberculosis. The clinical and radiographic findings were consistent with active pulmonary and pleural TB. The patient was initiated on standard RIPE therapy with rifampin, isoniazid, pyrazinamide, and ethambutol for two months, followed by rifampin and isoniazid for four additional months. Infectious Disease, Pulmonology, and public health authorities coordinated treatment and outpatient follow-up.

Discussion and Conclusion

This case illustrates the diagnostic challenges of active TB when initial AFB smear results are negative and emphasizes the importance of integrating clinical, radiographic, immunologic, and molecular findings. The temporal relationship between childbirth, prior pleural disease, and subsequent development of cavitary pulmonary TB raises the possibility that postpartum immune modulation contributed to reactivation of previously latent M. tuberculosis. Although a direct causal relationship cannot be established from a single case, postpartum immune alterations should be considered when evaluating patients with persistent respiratory symptoms and epidemiologic risk factors for TB.