Book traversal links for 6.4.1 Extensive DR-TB disease
Extensive (or advanced) TB disease in adults is defined as the presence of bilateral cavitary disease or extensive parenchymal damage on chest radiography. In children aged below 15 years, extensive (or advanced) disease is usually defined by the presence of cavities or bilateral disease on chest radiography. This highlights the importance of chest radiography as part of the diagnostic work-up for patients, along with bacteriological tests. Patients with extensive disease tend to have a higher bacterial burden, especially in cases of parenchymal lung destruction (e.g. lobe collapse, fibrotic tracts or atelectasis), where drug concentration might be low due to decreased tissue perfusion. These patients tend to benefit from longer regimens to decrease the chances of relapse on shorter regimens. Patterns of lung destruction tend to present a higher risk of negative outcomes such as treatment failure and clinical complication (e.g. bacterial, fungal or mycobacterial superinfections, bronchiectasis and respiratory failure). Disability after cure is frequent. Close follow-up is needed during and after TB treatment.