Posttuberculosis Lung Disease: The Invisible Comorbidity

The rapidly growing population of pulmonary tuberculosis survivors continuing to live with damaged lungs poses a new challenge for pulmonologists.1-3 For a substantial proportion of patients, microbiological cure, rather than signifying restoration of lung health, marks the beginning of progressive lung inflammation and loss of lung function now recognised as posttuberculosis lung disease (PTLD).4,5 In the research article in this issue by Anjali Babu, et al., the reported posttuberculosis residual radiologic sequelae on chest radiograph were around 78%. While the chronic burden of PTLD is increasingly recognized, its identification and impact on acute illness and perioperative outcomes remain underappreciated.6 Unrecognised PTLD silently modifies the course, complexity, cost, and outcomes of acute illness. PTLD, a predictor of chronic obstructive airway disease (OAD), could remain clinically silent for years, manifesting only when physiological reserve is challenged by infection, surgery, or critical illness.7 Patients may present much later with what appears to be “new-onset” lung disease, without a clear aetiological explanation. The remote history of tuberculosis is frequently forgotten or overlooked. PTLD presentation as “difficult-to-treat” OAD may result in weaning failure and need for tracheostomy. The reflex escalation of systemic steroids and antibiotic coverage in such cases may paradoxically worsen outcomes while offering limited physiological benefit. A defining yet under-recognized feature of PTLD is its ability to amplify the impact of otherwise mild illnesses; simple viral infections may lead to excessive sputum production, mucus plugging, segmental or lobar collapse, and hypoxemia, necessitating bronchoscopy or mechanical ventilation.8,9 This may be relevant in the perioperative period as well, if PTLD goes unidentified. In addition, distorted airway anatomy increases the procedural risk of intubation. During immunosuppressive therapy, concern regarding tuberculosis reactivation often complicates and delays clinical decision-making. PTLD inflates healthcare costs not solely through disease burden, but through diagnostic uncertainty and inefficient care pathways.9 PTLD frequently generates diagnostic ambiguity, leading to investigative cascades, such as chest radiographic opacities prompting advanced imaging and empirical antibiotics, or hemoptysis being misinterpreted as hematemesis, leading to unnecessary blood transfusion.1,8 A history of tuberculosis may also prompt unnecessary isolation measures, increasing expenses and psychological distress.10 While addressing potential risk factors of PTLD remains a research priority, the problem of under-recognition of PTLD needs to be tackled.1,6,9 A seemingly normal chest radiograph can obscure underlying structural lung damage, which may go unrecognized in routine clinical practice. Subtle but meaningful radiographic markers such as apical capping, faint lateral pleural opacity, or costophrenic angle blunting from remote pleural effusions are easily overlooked.1 Minor abnormalities like subtle fibrotic strands in high-resolution computed tomography chest may be dismissed as insignificant, despite possible disproportionate physiological vulnerability. Bridging this gap requires a shift in clinical thinking – from viewing posttuberculosis changes as radiological scars of the past to recognizing them as active determinants of present-day risk.11,12 Advocacy regarding the extent and clinical significance of PTLD, and heightened vigilance during preprocedural evaluation, may be effective and achievable strategies to reduce related morbidity in this population.