Post-tuberculosis pulmonary function and noninfectious pulmonary disorders

Tuberculosis (TB) is among the top infectious causes of morbidity and mortality worldwide and is associated with frequent pulmonary damage despite microbiological cure. Patients with treated TB may remain lifelong sufferers of disabling structural and functional sequelae of the disease, which subsequently impair quality of life. Long-term follow-up studies have revealed that many patients with treated pulmonary TB show signs of permanent impairment of their lung function. Impairment is variable in pattern and severity, ranging from none to severe, and shows restrictive, obstructive, or mixed patterns. Patients who presented with recurrent tuberculosis had a 2.8–3.0-fold higher likelihood of developing abnormal lung function at the end of treatment than those with a first episode of TB. A variety of noninfectious pulmonary disorders are also common in post-TB patients. (1) Parenchymal disorders that include thin-walled cavities (open negative syndrome), and lung fibrosis with structural destruction and scar carcinoma. (2) Airway disorders that include subglottic stenosis, chronic obstructive air flow obstruction, bronchiectasis, tracheobronchial stenosis, anthracofibrosis, and broncholithiasis. (3) Vascular lesions such as Rasmussen aneurysm. (4) Pleural lesions that range from pleural thickening to severe fibrothorax. (5) General complications that include cor pulmonale, secondary amyloidosis, and chronic respiratory failure. The prevalence of these abnormalities among patients completing anti-TB treatment is alarmingly high. In fact, some studies have suggested greater morbidity from the sequelae rather than from the disease itself. It is important to be aware of the full spectrum of these disorders to facilitate early diagnosis and management.