Radiologic manifestations of pulmonary tuberculosis

Abstract

In summary, the following points are reemphasized: 1. The chest film is the mainstay in the radiologic evaluation of suspected or proven pulmonary TB. CT is occasionally useful for clarifying confusing findings but has not been conclusively shown to have a significant impact on patient management. 2. Primary TB is increasingly a disease of adults. 3. Primary TB usually manifests as a parenchymal consolidation in any pulmonary lobe or segment. Distinguishing features from typical bacterial pneumonia include associated adenopathy, lack of systemic toxicity, failure to respond to conventional antibacterial therapy, and recent PPD conversion. 4. Associated ipsilateral hilar and/or mediastinal adenopathy is almost universal in children with primary TB but is less common in adults. Adenopathy without parenchymal disease is an unusual but well-reported manifestation. 5. Many of the so-called unusual manifestations of adult TB are the usual manifestations of primary disease. The terms adult and childhood TB should be discarded. 6. Postprimary TB typically manifests as a heterogeneous, often cavitary opacity in the apical and posterior segments of the upper lobes and the superior segments of the lower lobes. Lymphadenopathy is rare. 7. Activity of postprimary disease cannot be accurately assessed by chest radiography. Radiographic stability for 6 months and negative sputum cultures is the best indicator of inactive disease. The descriptive terms inactive or old TB should be discarded in favor of radiographically stable TB, as viable bacilli may persist despite adequate therapy. 8. Cavitation is the most important radiologic finding in postprimary disease. Cavitation implies a high bacillary burden, high infectivity, and is associated with numerous complications including endobronchial spread, tuberculous empyema, hematogenous dissemination, pulmonary artery pseudoaneurysm, and so forth. 9. Tuberculous pleurisy is more common in primary than postprimary disease. It is a common presenting manifestation in young adults. The effusions are unilateral, large, and self-limited. The pleural fluid usually is a serous exudate with a marked lymphocytosis. Fluid cultures are frequently negative. Correct diagnosis and therapy is important, as untreated patients are at high risk for subsequent pulmonary reactivation. 10. Miliary disease is also more common in primary than postprimary disease; however, its frequency in elderly patients with postprimary TB is increasing. This form, known as late generalized TB, is apt to be misdiagnosed or not diagnosed in life and has a high mortality.